Abstracts of BES Workshop and Technical Reports |
Provided below is
a listing of
BES-sponsored workshop reports that address the
current status and possible future directions of some important
research areas. These reports
include those resulting from
The “Basic Research Needs”
Workshop Series that are
used to help identify research directions for a
decades-to-century energy strategy. [PDF
file requirements]
Shorter listing of same reports |
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New Science for a Secure and Sustainable Energy Future
This Basic Energy Sciences Advisory Committee (BESAC)
report summarizes a 2008 study by the Subcommittee on Facing our Energy
Challenges in a New Era of Science to: (1) assimilate the scientific
research directions that emerged from the BES Basic Research Needs
workshop reports into a comprehensive set of science themes, and (2) identify
the new implementation strategies and tools required to accomplish the science.
The United States faces a three-fold energy challenge:
• Energy Independence. U.S. energy use exceeds
domestic production capacity by the equivalent of 16 million barrels of oil per
day, a deficit made up primarily by importing oil and natural gas. This
deficit has nearly tripled since 1970.
• Environmental Sustainability. The United States must reduce its
emissions of carbon dioxide and other greenhouse gases that accelerate climate
change. The primary source of these emissions is combustion of fossil
fuel, comprising about 85% of U.S. national energy supply.
• Economic Opportunity. The U.S. economy is threatened by the high
cost of imported energy—as much as $700 billion per year at recent peak prices.
We need to create next-generation clean energy technologies that do not depend
on imported oil. U.S. leadership would not only provide solutions at home
but also create global economic opportunity.
The magnitude of the challenge is so immense that existing energy
approaches—even with improvements from advanced engineering and improved
technology based on known concepts—will not be enough to secure our energy
future. Instead, meeting the challenge will require new technologies for
producing, storing and using energy with performance levels far beyond what is
now possible. Such technologies spring from scientific breakthroughs in
new materials and chemical processes that govern the transfer of energy between
light, electricity and chemical fuels. Integrating a major national mobilization
of basic energy research—to create needed breakthroughs—with appropriate
investments in technology and engineering to accelerate bringing new energy
solutions to market will be required to meet our three-fold energy challenge.
This report identifies three strategic goals for which transformational
scientific breakthroughs are urgently needed:
• Making fuels from sunlight
• Generating electricity without carbon dioxide emissions
• Revolutionizing energy efficiency and use
Meeting these goals implies dramatic changes in our technologies for producing
and consuming energy. We will manufacture chemical fuel from sunlight,
water and carbon dioxide instead of extracting it from the earth. We will
generate electricity from sunlight, wind, and high-efficiency clean coal and
advanced nuclear plants instead of conventional coal and nuclear technology.
Our cars and light trucks will be driven by efficient electric motors powered by
a new generation of batteries and fuel cells.
These new, advanced energy technologies, however, require new materials and
control of chemical change that operate at dramatically higher levels of
functionality and performance. Converting sunlight to electricity with double or
triple today’s efficiency, storing electricity in batteries or supercapacitors
at ten times today’s densities, or operating coal-fired and nuclear power plants
at far higher temperatures and efficiencies requires materials with atom by atom
design and control, tailored nanoscale structures where every atom has a
specific function. Such high performing materials would have complexity
far higher than today’s energy materials, approaching that of biological cells
and proteins. They would be able to seamlessly control the ebb and flow of
energy between chemical bonds, electrons, and light, and would be the foundation
of the alternative energy technologies of the future.
Creating these advanced materials and chemical processes requires characterizing
the structure and dynamics of matter at levels beyond our present reach.
The physical and chemical phenomena that capture, store and release energy take
place at the nanoscale, often involving subtle changes in single electrons or
atoms, on timescales faster than we can now resolve. Penetrating the
secrets of energy transformation between light, chemical bonds, and electrons
requires new observational tools capable of probing the still-hidden realms of
the ultrasmall and ultrafast. Observing the dynamics of energy flow
in electronic and molecular systems at these resolutions is necessary if we are
to learn to control their behavior.
Fundamental understanding of complex materials and chemical change based on
theory, computation and advanced simulation is essential to creating new energy
technologies. A working transistor was not developed until the theory of
electronic behavior on semiconductor surfaces was formulated. In
superconductivity, sweeping changes occurred in the field when a microscopic
theory of the mechanism of superconductivity was finally developed. As Nobel
Laureate Phillip Anderson has written, more is different: at each level of
complexity in science, new laws need to be discovered for breakthrough progress
to be made. Without such breakthroughs, future technologies will not be
realized. The digital revolution was only made possible by transistors—try to
imagine the information age with vacuum tubes. Nearly as ubiquitous are lasers,
the basis for modern day read-heads used in CDs, DVDs, and bar code scanners.
Lasers could not be developed until the quantum theory of light emission by
materials was understood.
These advances—high-performance materials enabling precise control of chemical
change, characterization tools probing the ultrafast and the ultrasmall, and new
understanding based on advanced theory and simulation—are the agents for moving
beyond incremental improvements and creating a truly secure and sustainable
energy future.
Given these tools, we can imagine, and achieve, revolutionary new energy
systems.
(List of recent BES workshop reports)
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Next-Generation Photon Sources for
Grand Challenges in Science and Energy
This Basic Energy Sciences Advisory Committee (BESAC)
report summarizes the results of an October 2008 Photon Workshop of the Subcommittee on Facing our Energy
Challenges in a New Era of Science to identify connections between major new
research opportunities and the capabilities of the next generation of light
sources. Particular emphasis was on energy-related research.The next
generation of sustainable energy technologies will revolve around
transformational new materials and chemical processes that convert energy
efficiently among photons, electrons, and chemical bonds. New materials that tap
sunlight, store electricity, or make fuel from splitting water or recycling
carbon dioxide will need to be much smarter and more functional than today’s
commodity-based energy materials. To control and catalyze chemical reactions or
to convert a solar photon to an electron requires coordination of multiple
steps, each carried out by customized materials and interfaces with designed
nanoscale structures. Such advanced materials are not found in nature the way we
find fossil fuels; they must be designed and fabricated to exacting standards,
using principles revealed by basic science. Success in this endeavor requires
probing, and ultimately controlling, the interactions among photons, electrons,
and chemical bonds on their natural length and time scales.
Control science—the application of knowledge at the frontier of science to
control phenomena and create new functionality—realized through the next
generation of ultraviolet and X-ray photon sources, has the potential to be
transformational for the life sciences and information technology, as well as
for sustainable energy. Current synchrotron-based light sources have
revolutionized macromolecular crystallography. The insights thus obtained are
largely in the domain of static structure. The opportunity is for next
generation light sources to extend these insights to the control of dynamic
phenomena through ultrafast pump-probe experiments, time-resolved coherent
imaging, and high-resolution spectroscopic imaging. Similarly, control of spin
and charge degrees of freedom in complex functional materials has the potential
not only to reveal the fundamental mechanisms of high-temperature
superconductivity, but also to lay the foundation for future generations of
information science.
This report identifies two aspects of energy science in which next-generation
ultraviolet and X-ray light sources will have the deepest and broadest impact:
• The temporal evolution of electrons, spins,
atoms, and chemical reactions, down to the femtosecond time scale.
• Spectroscopic and structural imaging of nano objects (or
nanoscale regions of inhomogeneous materials) with nanometer spatial resolution
and ultimate spectral resolution.
The dual advances of temporal and spatial resolution promised
by fourth-generation light sources ideally match the challenges of control
science. Femtosecond time resolution has opened completely new territory where
atomic motion can be followed in real time and electronic excitations and decay
processes can be followed over time. Coherent imaging with short-wavelength
radiation will make it possible to access the nanometer length scale, where
intrinsic quantum behavior becomes dominant. Performing spectroscopy on
individual nanometer-scale objects rather than on conglomerates will eliminate
the blurring of the energy levels induced by particle size and shape
distributions and reveal the energetics of single functional units. Energy
resolution limited only by the uncertainty relation is enabled by these
advances.
Current storage-ring-based light sources and their incremental enhancements
cannot meet the need for femtosecond time resolution, nanometer spatial
resolution, intrinsic energy resolution, full coherence over energy ranges up to
hard X-rays, and peak brilliance required to enable the new science outlined in
this report. In fact, the new, unexplored territory is so expansive that no
single currently imagined light source technology can fulfill the whole
potential. Both technological and economic challenges require resolution as we
move forward. For example, femtosecond time resolution and high peak brilliance
are required for following chemical reactions in real time, but lower peak
brilliance and high repetition rate are needed to avoid radiation damage in
high-resolution spatial imaging and to avoid space-charge broadening in
photoelectron spectroscopy and microscopy.
But light sources alone are not enough. The photons produced by next-generation
light sources must be measured by state-of-the-art experiments installed at
fully equipped end stations. Sophisticated detectors with unprecedented spatial,
temporal, and spectral resolution must be designed and created. The theory of
ultrafast phenomena that have never before been observed must be developed and
implemented. Enormous data sets of diffracted signals in reciprocal space and
across wide energy ranges must be collected and analyzed in real time so that
they can guide the ongoing experiments. These experimental challenges—end
stations, detectors, sophisticated experiments, theory, and data handling—must
be planned and provided for as part of the photon source. Furthermore, the
materials and chemical processes to be studied, often in situ, must be
synthesized and developed with equal care. These are the primary factors
determining the scientific and technological return on the photon source
investment.
Of equal or greater concern is the need for interdisciplinary platforms to solve
the grand challenges of sustainable energy, climate change, information
technology, biological complexity, and medicine. No longer are these challenges
confined to one measurement or one scientific discipline. Fundamental problems
in correlated electron materials, where charge, spin, and lattice modes interact
strongly, require experiments in electron, neutron, and X-ray scattering that
must be coordinated across platforms and user facilities and that integrate
synthesis and theory as well. The model of users applying for one-time access to
single-user facilities does not promote the coordinated, interdisciplinary
approach needed to solve today’s grand challenge problems. Next-generation light
sources and other user facilities must learn to accommodate the
interdisciplinary, cross-platform needs of modern grand challenge science. Only
through the development of such future sources, appropriately integrated with
advanced end stations and detectors and closely coupled with broader synthesis,
measurement, theory, and modeling tools, can we meet the demands of a New Era of
Science.
(List of recent BES workshop reports)
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Directing Matter and Energy:
Five Challenges for Science and the Imagination
This Basic Energy Sciences Advisory Committee (BESAC)
Grand Challenges report identifies the most important scientific questions and
science-driven technical challenges facing BES and describes the importance of
these challenges to advances in disciplinary science, to technology development,
and to energy and other societal needs. The report originated from a January 25,
2005, request from the Office of Science and is the product of numerous BESAC
and Grand Challenges Subcommittee meetings and conferences in 2006–2007.
It is frequently said that any
sufficiently advanced technology is indistinguishable from magic. Modern science
stands at the beginning of what might seem by today’s standards to be an almost
magical leap forward in our understanding and control of matter, energy, and
information at the molecular and atomic levels. Atoms—and the molecules they
form through the sharing or exchanging of electrons—are the building blocks of
the biological and non-biological materials that make up the world around us. In
the 20th century, scientists continually improved their ability to observe and
understand the interactions among atoms and molecules that determine material
properties and processes. Now, scientists are positioned to begin directing
those interactions and controlling the outcomes on a molecule-by-molecule and
atom-by-atom basis, or even at the level of electrons. Long the staple of
science- fiction novels and films, the ability to direct and control matter at
the quantum, atomic, and molecular levels creates enormous opportunities across
a wide spectrum of critical technologies. This ability will help us meet some of
humanity’s greatest needs, including the need for abundant, clean, and cheap
energy. However, generating, storing, and distributing adequate and sustainable
energy to the nation and the world will require a sea change in our ability to
control matter and energy.
One of the
most spectacular technological advances in the 20th century took place in the
field of information, as computers and microchips became ubiquitous in our
society. Vacuum tubes were replaced with transistors and, in accordance with
Moore’s Law (named for Intel co-founder Gordon Moore), the number of transistors
on a microchip has doubled approximately every two years for the past two
decades. However, if the time comes when integrated circuits can be fabricated
at the molecular or nanoscale level, the limits of Moore’s Law will be far
surpassed. A supercomputer based on nanochips would comfortably fit in the palm
of your hand and use less electricity than a cottage. All the information stored
in the Library of Congress could be contained in a memory the size of a sugar
cube. Ultimately, if computations can be carried out at the atomic or sub-nanoscale
levels, today’s most powerful microtechnology will seem as antiquated and slow
as an abacus.
For the
future, imagine a clean, cheap, and virtually unlimited supply of electrical
power from solar-energy systems modeled on the photosynthetic processes utilized
by green plants, and power lines that could transmit this electricity from the
deserts of the Southwest to the Eastern Seaboard at nearly 100-percent
efficiency. Imagine information and communications systems based on light rather
than electrons that could predict when and where hurricanes make landfall, along
with self-repairing materials that could survive those hurricanes. Imagine
synthetic materials fully compatible and able to communicate with biological
materials. This is speculative to be sure, but not so very far beyond the scope
of possibilities.
Acquiring
the ability to direct and control matter all the way down to molecular, atomic,
and electronic levels will require fundamental new knowledge in several critical
areas. This report was commissioned to define those knowledge areas and the
opportunities that lie beyond. Five interconnected Grand Challenges that will
pave the way to a science of control are identified in the regime of science
roughly defined by the Basic Energy Science portfolio, and recommendations are
presented for what must be done to meet them.
FIVE GRAND CHALLENGES FOR BASIC ENERGY SCIENCES
• How
do we control material processes at the level of electrons?
Electrons are the
negatively charged subatomic particles whose dynamics determine materials
properties and direct chemical,
electrical, magnetic, and physical processes. If we can learn to direct and
control material processes at the level of electrons, where the strange laws of
quantum mechanics rule, it should pave the way for artificial photosynthesis and
other highly efficient energy technologies, and could revolutionize computer
technologies.
• How do we design and perfect atom- and energy- efficient synthesis of
revolutionary new forms of matter with tailored properties?
Humans,
through trial and error experiments or through lucky accidents, have been able
to make only a tiny fraction of all the materials that are theoretically
possible. If we can learn to design and create new materials with tailored
properties, it could lead to low-cost photovoltaics, self-repairing and
self-regulating devices, integrated photonic (light-based) technologies, and
nano-sized electronic and mechanical devices.
•
How do remarkable properties of matter emerge from complex correlations of
the atomic or electronic constituents and how can we control these properties?
Emergent
phenomena, in which a complex outcome emerges from the correlated interactions
of many simple constituents, can be widely seen in nature, as in the
interactions of neurons in the human brain that result in the mind, the freezing
of water, or the giant magneto-resistance behavior that powers disk drives. If
we can learn the fundamental rules of correlations and emergence and then learn
how to control them, we could produce, among many possibilities, an entirely new
generation of materials that supersede present-day semiconductors and
superconductors.
•
How can we master energy and information on the nanoscale to create new
technologies with capabilities rivaling those of living things?
Biology is
nature’s version of nanotechnology, though the capabilities of biological
systems can exceed those of human technologies by a vast margin. If we can
understand biological functions and harness nanotechnologies with capabilities
as effective as those of biological systems, it should clear the way towards
profound advances in a great many scientific fields, including energy and
information technologies.
•
How do we characterize and control matter away—especially very far away—from
equilibrium?
All natural
and most human-induced phenomena occur in systems that are
away from the equilibrium in which the system would not
change with time. If we can understand system effects that
take place away—especially very far away—from equilibrium
and learn to control them, it could yield dramatic new
energy-capture and energy storage technologies, greatly
improve our predictions for molecular-level electronics, and
enable new mitigation strategies for environmental damage.
We now stand
at the brink of a "Control Age” that could spark revolutionary changes in
how we inhabit our planet, paving the way to a bright and sustainable future for
us all. But answering the call of the five Grand Challenges for Basic Energy
Science will require that we change our fundamental understanding of how nature
works. This will necessitate a three-fold attack: new approaches to training and
funding, development of instruments more precise and flexible than those used up
to now for observational science, and creation of new theories and concepts
beyond those we currently possess. The difficulties involved in this change of
our understanding are huge, but the rewards for success should be extraordinary.
If we succeed in meeting these five Grand Challenges, our ability to direct and
control matter might one day be measured only by the limits of human
imagination.
(List of recent BES workshop reports)
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Basic Research Needs for Materials under Extreme Environments
This report is based on a BES Workshop on Basic
Research Needs for Materials under
Extreme Environments, June 11–13, 2007, to evaluate the potential for developing
revolutionary new materials that will meet demanding future energy requirements
that expose materials to environmental extremes.
Never has the world been so acutely aware of the inextricably
linked issues of energy, environment, economy, and security. As the economies of
developing countries boom, so does their demand for energy. Today nearly a
quarter of the world does not have electrical power, yet the demand for
electricity is projected to more than double over the next two decades.
Increased demand for energy to power factories, transport commodities and
people, and heat/cool homes also results in increased CO2
emissions. In 2007 China, a major consumer of coal, surpassed the United States
in overall carbon dioxide emissions. As global CO2
emissions grow, the urgency grows to produce energy from carbon-based sources
more efficiently in the near term and to move to non-carbon-based energy
sources, such as solar, hydrogen, or nuclear, in the longer term. As we look
toward the future, two points are very clear: (1) the economy and security of
this nation is critically dependent on a readily available, clean and affordable
energy supply; and (2) no one energy solution will meet all future energy
demands, requiring investments in development of multiple energy technologies.
Materials are central to every energy technology, and future energy technologies
will place increasing demands on materials performance with respect to extremes
in stress, strain, temperature, pressure, chemical reactivity, photon or
radiation flux, and electric or magnetic fields. For example, today’s
state-of-the-art coal-fired power plants operate at about 35% efficiency.
Increasing this efficiency to 60% using supercritical steam requires raising
operating temperatures by nearly 50% and essentially doubling the operating
pressures. These operating conditions require new materials that can reliably
withstand these extreme thermal and pressure environments. To lower fuel
consumption in transportation, future vehicles will demand lighter weight
components with high strength. Next-generation nuclear fission reactors require
materials capable of withstanding higher temperatures and higher radiation flux
in highly corrosive environments for long periods of time without failure. These
increasingly extreme operating environments accelerate the aging process in
materials, leading to reduced performance and eventually to failure. If one
extreme is harmful, two or more can be devastating. High temperature, for
example, not only weakens chemical bonds, it also speeds up the chemical
reactions of corrosion.
Often materials fail at one-tenth or less of their intrinsic limits, and we do
not understand why. This failure of materials is a principal bottleneck for
developing future energy technologies that require placing materials under
increasingly extreme conditions. Reaching the intrinsic limit of materials
performance requires understanding the atomic and molecular origins of this
failure. This knowledge would enable an increase in materials performance of
order of magnitude or more. Further, understanding how these extreme
environments affect the physical and chemical processes that occur in the bulk
material and at its surface would open the door to employing these conditions to
make entirely new classes of materials with greatly enhanced performance for
future energy technologies. This knowledge will not be achieved by incremental
advances in materials science. Indeed, this knowledge will only be gained by
innovative basic research that will unlock the fundamentals of how extremes
environments interact with materials and how these interactions can be
controlled to reach the intrinsic limits of materials performance and to develop
revolutionary new materials. These new materials would have enormous impact for
the development of future energy technologies: extending lifetimes, increasing
efficiencies, providing novel capabilities, and lowering costs. Beyond energy
applications, these new materials would have a huge impact on other areas of
importance to this nation, including national security, industry, and other
areas where robust, reliable materials are required.
This report summarizes the research directions identified by a Basic Energy
Sciences Workshop on Basic Research Needs for Materials under Extreme
Environments, held in June 2007. More than 140 invited scientists and engineers
from academia, industry, and the national laboratories attended the workshop,
along with representatives from other offices within the Department of Energy,
including the National Nuclear Security Administration, the Office of Nuclear
Energy, the Office of Energy Efficiency and Renewable Energy, and the Office of Fossil Energy.
Prior to the workshop, a technology resource document, Technology and Applied
R&D Needs for Materials under Extreme Environments, was prepared that provided
the participants with an overview of current and future materials needs for
energy technologies. The workshop began with a plenary session that outlined the
technology needs and the state of the art in research of materials under extreme
conditions. The workshop was then divided into four panels, focusing on specific
types of extreme environments: Energetic Flux Extremes, Chemical Reactive
Extremes, Thermomechanical Extremes, and Electromagnetic Extremes. The four
panels were asked to assess the current status of research in each of these four
areas and identify the most promising research directions that would bridge the
current knowledge gaps in understanding how these four extreme environments
impact materials at the atomic and molecular levels. The goal was to outline
specific Priority Research Directions (PRDs) that would ultimately lead to the
development of vastly improved materials across a broad range of future energy
technologies. During the course of the workshop, a number of common themes
emerged across these four panels and a fifth panel was charged to identify these
cross-cutting research areas.
Photons and energetic particles can cause damage to materials that occurs over
broad time and length scales. While initiation, characterized by localized
melting and re-crystallization, may occur in fractions of a picosecond, this
process can produce cascades of point defects that diffuse and agglomerate into
larger clusters. These nanoscale clusters can eventually reach macroscopic
dimensions, leading to decreased performance and failure. The panel on energetic
flux extremes noted that this degradation and failure is a key barrier to
achieving more efficient energy generation systems and limits the lifetime of
materials used in photovoltaics, solar collectors, nuclear reactors, optics,
electronics and other energy and security systems used in extreme flux
environments. The panel concluded that the ability to prevent this degradation
from extreme fluxes is critically dependent on being able to elucidate the
atomic- and molecular-level mechanisms of defect production and damage evolution
triggered by single and multiple energetic particles and photons interacting
with materials. Advances in characterization and computational tools have the
potential to provide an unprecedented opportunity to elucidate these key
mechanisms. In particular, ultrafast and ultra-high spatial resolution
characterization tools will allow the initial atomic-scale damage events to be
observed. Further, advanced computational capabilities have the potential to
capture multiscale damage evolution from atomic to macroscopic dimensions.
Elucidation of these mechanisms would allow the complex pathways of damage
evolution from the atomic to the macroscopic scale to be understood. This
knowledge would ultimately allow atomic and molecular structures to be
manipulated in a predicable manner to create new materials that have
extraordinary tolerance and can function within an extreme environment without
property degradation. Further, it would provide revolutionary capabilities for
synthesizing materials with novel structures or, alternatively, to force
chemical reactions that normally result in damage to proceed along selected
pathways that are either benign or self-repair damage initiation.
Chemically reactive extreme environments are found in many advanced energy
systems, including fuel cells, nuclear reactors, and batteries, among others.
These conditions include aqueous and non-aqueous liquids (such as mineral acids,
alcohols, and ionic liquids) and gaseous environments (such as hydrogen,
ammonia, and steam). The panel evaluating extreme chemical environments
concluded there is a lack of fundamental understanding of thermodynamic and
kinetic processes that occur at the atomic level under these important reactive
environments. The chemically induced degradation of materials is initiated at
the interface of a material with its environment. Chemical stability in these
environments is often controlled by protective surfaces, either self-healing,
stable films that form on a surface (such as oxides) or by coatings that are
applied to a surface. Besides providing surface stability, these films must also
prevent facile mass transport of reactive species into the bulk of the material.
While some films can have long lifetimes, increasing severity of environments
can cause the films to break down, leading to costly materials failure. A major
challenge therefore is to develop a new generation of surface layers that are
extremely robust under aggressive chemical conditions. Before this can be
accomplished, however, it is critical to understand the equilibrium and
non-equilibrium thermodynamics and reaction kinetics that occur at the atomic
level at the interface of the protective film with its environment. The
stability of the film can be further complicated by differences in the
material’s morphology, structure, and defects. It is critical that these complex
and interrelated chemical and physical processes be understood at the nanoscale
using new capabilities in materials characterization and theory, modeling, and
simulation. Armed with this information, it will be possible to develop a new
generation of robust surface films to protect materials in extreme chemical
environments. Further, this understanding will provide insight into developing
films that can self-heal and to synthesizing new classes of materials that have
unimaginable stability to aggressive chemical environments.
The need for materials that can withstand thermomechanical extremes—high
pressure and stress, strain and strain rate, and high and low temperature—is
found across a broad range of energy technologies, such as efficient steam
turbines and heat exchangers, fuel-efficient vehicles, and strong wind turbine
blades. Failures of materials under thermomechanical extremes can be
catastrophic and costly. The panel on thermomechanical extremes concluded that
designing new materials with properties specifically tailored to withstand
thermomechanical extremes must begin with understanding the fundamental chemical
and physical processes involved in materials failure, extending from the
nanoscale to the collective behavior at the macroscale. Further, the behavior of
materials must be understood under static, quasistatic, and dynamic
thermomechanical extremes. This requires learning how atoms and electrons move
within a material under extremes to provide insight into defect production and
eventual evolution into microstructural components, such as dislocations, voids,
and grain boundaries. This will require advanced analytical tools that can study
materials in situ as these defects originate and evolve. Once these processes
are understood, it will be possible to predict responses of materials under
thermomechanical extremes using advanced computation tools. Further, this
fundamental knowledge will open new avenues for designing and synthesizing
materials with unique properties. Using these thermomechanical extremes will
allow the very nature of chemical bonds to be tuned to produce revolutionary new
materials, such as ultrahard materials.
As electrical energy demand grows, perhaps by greater than 70% over the next 50
years, so does the need to develop materials capable of operating at extreme
electric and magnetic fields. To develop future electrical energy technologies,
new materials are needed for magnets capable of operating at higher fields in
generators and motors, insulators resistant to higher electric fields and field
gradients, and conductors/superconductors capable of carrying higher current at
lower voltage. The panel on electromagnetic extremes concluded that the
discovery and understanding of this broad range of new materials requires
revealing and controlling the defects that occur at the nanoscale. Defects are
responsible for breakdown of insulators, yet defects are needed within local
structures of superconductors to trap magnetic vortices. The ability to observe
these defects as materials interact with electromagnetic extremes is just
becoming available with advances in characterization tools with increased
spatial and time resolution. Understanding how these nanoscale defects evolve to
affect the macroscale behavior of materials is a grand challenge, and advances
in multiscale modeling are required to understand the behavior of materials
under these extremes. Once the behavior of defects in materials is understood,
then materials could be designed to prevent dielectric breakdown or to enhance
magnetic behavior. For example, composite materials having appropriate
structures and properties could be tailored using nanoscale self-assembly
techniques. The panel projected that understanding how electric and magnetic
fields affect materials at the atomic and molecular level could lead to the
ability to control materials properties and synthesis. Such control would lead
to a new generation of materials that is just emerging today—such as
electrooptic materials that can be switched between transparency and opacity
through application of electric fields. Beyond energy applications, these
tailored materials could have enormous importance in security, computing,
electronics, and other applications.
During the course of the workshop, four recurring science issues emerged as
important themes: (1) Achieving the Limits of Performance; (2) Exploiting
Extreme Environments for Materials Design and Synthesis; (3) Characterization on
the Scale of Fundamental Interactions; and (4) Predicting and Modeling
Materials Performance. All four of the workshop panels identified the need
to understand the complex and interrelated physical and chemical processes that
control the various performance limits of materials subjected to extreme
conditions as the major technical bottleneck in meeting future energy needs.
Most of these processes involve understanding the cascade of events that is
initiated at atomic-level defects and progresses through macroscopic materials
properties. By understanding various mechanisms by which materials fail, for
example, it may be possible to increase the performance and lifetime limits of
materials by an order of magnitude or more and thereby achieve the true limits
of materials performance.
Understanding the atomic and molecular basis of the interaction of extreme
environments with materials provides an exciting and unique opportunity to
produce entirely new classes of materials. Today materials are made primarily by
changing temperature, composition, and sometimes, pressure. The panels concluded
that extreme conditions—in the form of high temperatures, pressures, strain
rate, radiation fluxes, or external fields, alone or in combination—can
potentially be used as new “knobs” that can be manipulated for the synthesis of
revolutionary new materials. All four of the extreme environments offer new
strategies for controlling the atomic- and molecular-level structure in
unprecedented ways to produce materials with tailored functionalities.
To achieve the breakthroughs needed to understand the atomic and molecular
processes that occur within the bulk and at surfaces in materials in extreme
environments will require advances in the final two cross-cutting areas,
characterization and computation. Elucidating changes in structure and dynamics
over broad timescales (femtoseconds to many seconds) and length scales (nanoscale
to macroscale) is critical to realizing the revolutionary materials required for
future energy technologies. Advances in characterization tools, including
diffraction, scattering, spectroscopy, microscopy, and imaging, can provide this
critical information. Of particular importance is the need to combine two or
more of these characterization tools to permit so-called “multi-dimensional”
analysis of materials and surfaces in situ. These advances will enable the
elucidation of fundamental chemical and physical mechanisms that are at the
heart of materials performance (and failure) and catalyze the discovery of new
materials required for the next generation of energy technologies.
Complementing these characterization techniques are computational techniques
required for modeling and predicting materials behavior under extreme
conditions. Recent advances in theory and algorithms, coupled with enormous and
growing computational power and ever more sophisticated experimental methods,
are opening up exciting new possibilities for taking advantage of predictive
theory and simulation to design and predict of the properties and performance of
new materials required for extreme environments. New theoretical tools are
needed to describe new phenomena and processes that occur under extreme
conditions. These various tools need to be integrated across broad length
scales—atomic to macroscopic—to model and predict the properties of real
materials in response to extreme environments. Together with advanced synthesis
and characterization techniques, these new capabilities in theory and modeling
offer exciting new capabilities to accelerate scientific discovery and shorten
the development cycle from discovery to application.
In concluding the workshop, the panelists were confident that today’s gaps in
materials performance under extreme conditions could be bridged if the physical
and chemical changes that occur in bulk materials and at the interface with the
extreme environment could be understood from the atomic to macroscopic scale.
These complex and interrelated phenomena can be unraveled as advances are
realized in characterization and computational tools. These advances will allow
structural changes, including defects, to be observed in real time and then
modeled so the response of materials can be predicted. The concept of exploiting
these extreme environments to create revolutionary new materials was viewed to
be particularly exciting. Adding these parameters to the toolkit of materials
synthesis opens unimaginable possibilities for developing materials with
tailored properties. The knowledge needed for bridging these technology gaps
requires significant investment in basic research, and this research needs to be
coupled closely with the applied research and technology communities and
industry that will drive future energy technologies. These investments in
fundamental research of materials under extreme conditions will have a major
impact on the development of technologies that can meet future requirements for
abundant, affordable, and clean energy. However, this research will enable the
development of materials that will have a much broader impact in other
applications that are critical to the security and economy of this nation.
(List of recent BES workshop reports)
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Basic Research Needs: Catalysis for Energy
This report is based on a BES Workshop on Basic
Research Needs in Catalysis for Energy Applications, August 6–8, 2007, to
identify research needs and opportunities for catalysis to meet the nation’s
energy needs, provide an assessment of where the science and technology now
stand, and recommend the directions for fundamental research that should be
pursued to meet the goals described.
The United States continues to
rely on petroleum and natural gas as its primary sources of fuels. As the
domestic reserves of these feedstocks decline, the volumes of imported fuels
grow, and the environmental impacts resulting from fossil fuel combustion become
severe, we as a nation must earnestly reassess our energy future.
Catalysis—the essential
technology for accelerating and directing chemical transformation—is the key to
realizing environmentally friendly, economical processes for the conversion of
fossil energy feedstocks. Catalysis also is the key to developing new
technologies for converting alternative feedstocks, such as biomass, carbon
dioxide, and water.
With the declining availability
of light petroleum feedstocks that are high in hydrogen and low in sulfur and
nitrogen, energy producers are turning to ever-heavier fossil feedstocks,
including heavy oils, tar sands, shale oil, and coal. Unfortunately, the heavy
feedstocks yield less fuel than light petroleum and contain more sulfur and
nitrogen. To meet the demands for fuels, a deep understanding of the chemistry
of complex fossil-energy feedstocks will be required together with such
understanding of how to design catalysts for processing these feedstocks.
The United States has the
capacity to grow and convert enough biomass to replace nearly a third of the
nation’s current gasoline use. Building on catalysis for petroleum conversion,
researchers have identified potential catalytic routes for biomass. However,
biomass differs so much in composition and reactivity from fossil fuels that
this starting point is inadequate. The technology for economically converting
biomass into widely usable fuels does not exist, and the science underpinning
its development is only now starting to emerge.
The challenge is to understand
the chemistry by which cellulose- and lignin-derived molecules are converted to
fuels and to use this knowledge as a basis for identifying the needed catalysts.
To obtain energy densities similar to those of currently used fuels, the
products of biomass conversion must have oxygen contents lower than that of
biomass. Oxygen must be removed by using hydrogen derived from biomass or other
sources in a manner that minimizes the yield of carbon dioxide as a byproduct.
Catalytic conversion of carbon
dioxide into liquid fuels using solar and electrical energy would enable the
carbon in carbon dioxide to be recycled into fuels, thereby reducing its
contribution to atmospheric warming. Likewise, the catalytic generation of
hydrogen from water could provide a carbon-free source of hydrogen for fuel and
for processing of fossil and biomass feedstocks. The underlying science is far
from sufficient for design of efficient catalysts and economical processes.
Grand Challenges
To realize the full potential
of catalysis for energy applications, scientists must develop a profound
understanding of catalytic transformations so that they can design and build
effective catalysts with atom-by-atom precision and convert reactants to
products with molecular precision. Moreover, they must build tools to make
real-time, spatially resolved measurements of operating catalysts. Ultimately,
scientists must use these tools to achieve a fundamental understanding of
catalytic processes occurring in multiscale, multiphase environments.
The first grand challenge
identified in this report centers on understanding mechanisms and dynamics
of catalyzed reactions. Catalysis involves chemical transformations that
must be understood at the atomic scale because catalytic reactions present an
intricate dance of chemical bond-breaking and bond-forming steps. Structures of
solid catalyst surfaces, where the reactions occur on only a few isolated sites
and in the presence of highly complex mixtures of molecules interacting with the
surface in myriad ways, are extremely difficult to describe.
To discover new knowledge about
mechanisms and dynamics of catalyzed reactions, scientists need to image
surfaces at the atomic scale and probe the structures and energetics of the
reacting molecules on varying time and length scales. They also need to apply
theory to validate the results.
The difficulties of developing
a clear understanding of the mechanisms and dynamics of catalyzed reactions are
magnified by the high temperatures and pressures at which the reactions occur
and the influence of the molecules undergoing transformation on the catalyst.
The catalyst structure changes as the reacting molecules become part of it en
route to forming products. Although the scientific challenge of understanding
catalyst structure and function is great, recent advances in characterization
science and facilities provide the means for meeting it in the long term.
The second grand challenge in
the report centers on design and controlled synthesis of catalyst
structures. Fundamental investigations of catalyst structures and the
mechanisms of catalytic reactions provide the necessary foundation for the
synthesis of improved catalysts. Theory can serve as a predictive design tool,
guiding synthetic approaches for construction of materials with precisely
designed catalytic surface structures at the nano and atomic scales.
Success in the design and
controlled synthesis of catalytic structures requires an interplay between (1)
characterization of catalysts as they function, including evaluation of their
performance under technologically realistic conditions, and (2) synthesis of
catalyst structures to achieve high activity and product selectivity.
Priority Research Directions
The workshop process identified
three priority research directions for advancing catalysis science for energy
applications:
Advanced catalysts for the
conversion of heavy fossil energy feedstocks
The depletion of light, sweet
crude oil has caused increasing use of heavy oils and other heavy feedstocks.
The complicated nature of the molecules in these feedstocks, as well as their
high heteroatom contents, requires catalysts and processing routes entirely
different from those used in today’s petroleum refineries.
To advance catalytic
technologies for converting heavy feedstocks, scientists must (1) identify and
quantify the heavy molecules (now possible with methods such as high-resolution
mass spectrometry) and (2) determine data to represent the reactivities of the
molecules in the presence of the countless other kinds of molecules interacting
with the catalysts.
Methods for determining
reactivities of individual compounds within complex feedstocks reacting under
industrial conditions soon will be available. Reactivity data, when combined
with fundamental understanding of how the reactants interact with the catalysts,
will facilitate the selection of new catalysts for heavy feedstocks and the
prediction of properties of the fuels produced.
Understanding the chemistry of
lignocellulosic biomass deconstruction and conversion to fuels
The United States potentially
could harvest 1.3 billion tons of biomass annually. Converting this resource to
ethanol would produce more than 60 billion gallons/year, enough to replace 30
percent of the nation’s current gasoline use.
Scientists must develop
fundamental understanding of biomass deconstruction, either through
high-temperature pyrolysis or low-temperature catalytic conversion, before
engineers can create commercial biomass conversion technologies. Pyrolysis
generates gases and liquids for processing into fuels or blending with existing
petroleum refinery streams. Low-temperature deconstruction produces sugars and
lignin for conversion into molecules with higher energy densities than the
parent biomass.
Scientists also must discover
and develop new catalysts for targeted transformations of these biomass-derived
molecules into fuels. Developing a molecular-scale understanding of
deconstruction and conversion of biomass products to fuels would contribute to
the development of optimal processes for particular biomass sources. Knowledge
of how catalyst structure and composition affect the kinetics of individual
processes could lead to new catalysts with properties adjusted for maximum
activity and selectivity for high- and low-temperature processing of biomass.
Photo- and electro-driven
conversions of carbon dioxide and water
Catalytic conversion of carbon
dioxide to liquid fuels facilitated by the input of solar or electrical energy
presents an immense opportunity for new sources of energy. Furthermore, the
catalytic generation of hydrogen from water could provide a carbon-free source
of hydrogen for fuel and for processing of fossil and biomass feedstocks.
Although these electrolytic processes are possible, they are not now economical,
because they depend on expensive and rare materials, such as platinum, and
require significantly more energy than the minimum dictated by thermodynamics.
Scientists have explored the
use of photons to drive thermodynamically uphill reactions, but the efficiencies
of the best-known processes are very low. To dramatically increase efficiencies,
we need to understand the elementary processes by which photocatalysts and
electrocatalysts operate and the phenomena that limit their effectiveness. This
knowledge would guide the search for more efficient catalysts.
To address the challenge of
increased efficiency, scientists must develop fundamental understanding on the
basis of novel spectroscopic methods to probe the surfaces of photocatalysts and
electrocatalysts in the presence of liquid electrolytes. New catalysts will have
to involve multiple-site structures and be able to drive the multiple-electron
and hydrogen transfer reactions required to produce fuels from carbon dioxide
and water. Theoretical investigations also are needed to understand the manifold
processes occurring on photocatalysts and electrocatalysts, many of which are
unique to the conditions of their use. Basic research to address these
challenges will result in fundamental knowledge and expertise crucial for
developing efficient, durable, and scalable catalysts.
Crosscutting Research Issues
Two broad issues cut across the
grand challenges and the priority research directions for development of
efficient, economical, and environmentally friendly catalytic processes for
energy applications:
Experimental characterization
of catalysts as
they function is a theme common to all the processes mentioned here—ranging from
heavy feedstock refining to carbon dioxide conversion to fuels. The scientific
community needs a fundamental understanding of catalyst structures and catalytic
reaction mechanisms to design and prepare improved catalysts and processes for
energy conversion. Attainment of this understanding requires development of new
techniques and facilities for investigating catalysts as they function in the
presence of complex, real feedstocks at high temperatures and pressures.
The community also needs
improved methods for characterizing the feedstocks and products—to the point of
identifying individual compounds in these complex mixtures. The dearth of
information characterizing biomass-derived feedstocks and the growing complexity
of the available heavy fossil feedstocks, as well as the intrinsic complexity of
catalyst surfaces, magnify the difficulty of this challenge.
Implied in the need for better
characterization is the need for advanced methods and instrument hardware and
software far beyond today’s capabilities. Improved spectroscopic and microscopic
capabilities, specifically including synchrotron-based equipment and methods,
will provide significantly enhanced temporal, spatial, and energy resolution of
catalysts and new opportunities for elucidating their performance under
realistic reaction conditions.
Achieving these crosscutting
goals for better catalyst characterization will require breakthrough
developments in techniques and much improved methodologies for combining
multiple complementary techniques.
Advances in theory and
computation are also required to significantly advance catalysis for
energy applications. A major challenge is to understand the mechanisms and
dynamics of catalyzed transformations, enabling rational design of catalysts.
Molecular-level understanding is essential to “tune” a catalyst to produce the
right products with minimal energy consumption and environmental impact.
Applications of computational chemistry and methods derived from advanced
chemical theory are crucial to the development of fundamental understanding of
catalytic processes and ultimately to first-principles catalyst design.
Development of this understanding requires breakthroughs in theoretical and
computational methods to allow treatment of the complexity of the molecular
reactants and condensed-phase and interfacial catalysts needed to convert new
energy feedstocks to useful products.
Computation, when combined with
advanced experimental techniques, is already leading to broad new insights into
catalyst behavior and the design of new materials. The development of new
theories and computational tools that accurately predict thermodynamic
properties, dynamical behavior, and coupled kinetics of complex condensed-phase
and interfacial processes is a crosscutting priority research direction to
address the grand challenges of catalysis science, especially in the area of
advanced energy technologies.
Scientific and Technological
Impact
The urgent need for fuels in an
era of declining resources and pressing environmental concerns demands a
resurgence in catalysis science, requiring a massive commitment of programmatic
leadership and improved experimental and theoretical methods. These elements
will make it possible to follow, in real time, catalytic reactions on an atomic
scale on surfaces that are nonuniform and laden with large molecules undergoing
complex competing processes. The understanding that will emerge promises to
engender technology for economical catalytic processing of ever more challenging
fossil feedstocks and for breakthroughs needed to create an industry for energy
production from biomass. These new technologies are needed for a sustainable
supply of energy from domestic sources and mitigation of the problem of
greenhouse gas emissions.
(List of recent BES workshop reports)
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Future Science Needs and Opportunities for Electron Scattering:
Next-Generation Instrumentation and Beyond
This report is based on a BES Workshop entitled
"Future Science Needs and Opportunities for Electron Scattering: Next-Generation
Instrumentation and Beyond," March 1–2, 2007, to identify emerging basic science
and engineering research needs and opportunities that will require major
advances in electron-scattering theory, technology, and instrumentation.
The workshop was organized to
help define the scientific context and strategic priorities for the U.S.
Department of Energy’s Office of Basic Energy Sciences (DOE-BES)
electron-scattering development for materials characterization over the next
decade and beyond. Attendees represented university, national laboratory, and
commercial research organizations from the United States and around the world.
The workshop comprised plenary sessions, breakout groups, and joint open
discussion summary sessions. Complete information about this workshop is
available at
http://www.amc.anl.gov/DoE-ElectronScatteringWorkshop-2007
SCIENTIFIC CHALLENGES FACING
THE CHARACTERIZATION OF MATERIALS
In the last 40 years, advances
in instrumentation have gradually increased the resolution capabilities of
commercial electron microscopes. Within the last decade, however, a revolution
has occurred, facilitating 1-nm resolution in the scanning electron microscope
and sub-Ångstrom resolution in the transmission electron microscope. This
revolution was a direct result of decades-long research efforts concentrating on
electron optics, both theoretically and in practice, leading to implementation
of aberration correctors that employ multi-pole electron lenses. While this
improvement has been a remarkable achievement, it has also inspired the
scientific community to ask what other capabilities are required beyond “image
resolution” to more fully address the scientific problems of today’s
technologically complex materials. During this workshop, a number of scientific
challenges requiring breakthroughs in electron scattering and/or instrumentation
for characterization of materials were identified. Although the individual
scientific problems identified in the workshop were wide-ranging, they are well
represented by seven major scientific challenges. These are listed in Table 1,
together with their associated application areas as proposed by workshop
attendees. Addressing these challenges will require dedicated long-term
developmental efforts similar to those that have been applied to the electron
optics revolution. This report summarizes the scientific challenges identified
by attendees and then outlines the technological issues that need to be
addressed by a long-term research and development (R&D) effort to overcome these
challenges.
TECHNOLOGICAL CHALLENGES
A recurring message voiced
during the meeting was that, while improved image resolution in commercially
available tools is significant, this is only the first of many breakthroughs
required to answer today’s most challenging problems. The major technological
issues that were identified, as well as a measure of their relative priority,
appear in Table 2. These issues require not only the development of innovative
instrumentation but also new analytical procedures that connect experiment,
theory, and modeling.
Table 1
Scientific Challenges and
Applications Areas Identified during the Workshop
Theme |
Application Area |
1. The nanoscale
origin of macroscopic properties |
High-performance
21st century materials in both structural engineering and electronic
applications |
2. The role of
individual atoms, point defects, and dopants in materials |
Semiconductors,
catalysts, quantum phenomena and confinement, fracture,
embrittlement, solar energy, nuclear power, radiation damage |
3. Characterization
of interfaces at arbitrary orientations |
Semiconductors,
three-dimensional geometries for nanostructures,
grain-boundary-dominated processes, hydrogen storage |
4. The interface
between ordered and disordered materials |
Dynamic behavior of
the liquid-solid interface, organic/inorganic interfaces,
friction/wear, grain boundaries, welding, polymer/metal/oxide
composites, self-assembly |
5. Mapping of
electromagnetic (EM) fields in and around nanoscale matter |
Ferroelectric/magnetic structures, switching, tunneling and
transport, quantum confinement/proximity, superconductivity |
6. Probing
structures in their native environments |
Catalysis, fuel
cells, organic/inorganic interfaces, functionalized nanoparticles
for health care, polymers, biomolecular processes, biomaterials,
soft-condensed matter, non-vacuum environments |
7. The behavior of
matter far from equilibrium |
High radiation,
high-pressure and high-temperature environments, dynamic/transient
behavior, nuclear and fusion energy, outer space, nucleation, growth
and synthesis in solution, corrosion, phase transformations |
Table
2 Functionality
Required to Address Challenges in Table 1
|
Functionality
Required |
Priority |
1 |
In-situ
environments permitting observation of processes under conditions
that replicate real-world/real-time conditions (temperature,
pressure, atmosphere, EM fields, fluids) with minimal loss of image
and/or spectral resolution |
A |
2 |
Detectors that
enhance by more than an order of magnitude the temporal, spatial,
and/or collection efficiency of existing technologies for electrons,
photons, and/or X-rays |
A |
3 |
Higher temporal
resolution instruments for dynamic studies with a continuous range
of operating conditions from microseconds to femtoseconds A 4.
Sources having higher brightness, temporal resolution, and
polarization |
A |
4 |
Sources having
higher brightness, temporal resolution, and polarization |
B |
5 |
Electron-optical
configurations designed to study complex interactions of nanoscale
objects under multiple excitation processes (photons, fields, ….) |
B |
6 |
Virtualized
instruments that are operating in connection with experimental
tools, allowing real-time data quantitative analysis or simulation,
and community software tools for routine and robust data analysis |
C |
Some research efforts have
already begun to address these topics. However, a dedicated and coordinated
approach is needed to address these challenges more rapidly. For example, the
principles of aberration correction for electron-optical lenses were established
theoretically by Scherzer (Zeitschrift für Physik 101(9–10), 593–603) in
1936, but practical implementation was not realized until 1997 (a 61-year
development cycle). Reducing development time to less than a decade is essential
in addressing the scientific issues in the ever-growing nanoscale materials
world. To accomplish this, DOE should make a concerted effort to revise how it
funds advanced resources and R&D for electron beam instrumentation across its
programs.
(List of recent BES workshop reports)
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Basic
Research Needs for Electrical Energy Storage
This report is based on a BES Workshop on
Basic Research Needs for Electrical Energy Storage (EES),
April 2–4, 2007, to identify basic research needs and opportunities underlying
batteries, capacitors, and related EES technologies, with a focus on new or
emerging science challenges with potential for significant long-term impact on
the efficient storage and release of electrical energy.
The projected doubling of world energy consumption within the next 50 years,
coupled with the growing demand for low- or even zero-emission sources of
energy, has brought increasing awareness of the need for efficient, clean, and
renewable energy sources. Energy based on electricity that can be
generated from renewable sources, such as solar or wind, offers enormous
potential for meeting future energy demands. However, the use of
electricity generated from these intermittent, renewable sources requires
efficient electrical energy storage. For commercial and residential grid
applications, electricity must be reliably available 24 hours a day; even
second-to-second fluctuations cause major disruptions with costs estimated to be
tens of billions of dollars annually. Thus, for large-scale solar- or
wind-based electrical generation to be practical, the development of new EES
systems will be critical to meeting continuous energy demands and effectively
leveling the cyclic nature of these energy sources. In addition, greatly
improved EES systems are needed to progress from today’s hybrid electric
vehicles to plug-in hybrids or all-electric vehicles. Improvements in EES
reliability and safety are also needed to prevent premature, and sometimes
catastrophic, device failure. Chemical energy storage devices (batteries)
and electrochemical capacitors (ECs) are among the leading EES technologies
today. Both are based on electrochemistry, and the fundamental difference
between them is that batteries store energy in chemical reactants capable of
generating charge, whereas electrochemical capacitors store energy directly as
charge.
The performance of current EES technologies falls well short of requirements for
using electrical energy efficiently in transportation, commercial, and
residential applications. For example, EES devices with substantially
higher energy and power densities and faster recharge times are needed if
all-electric/plug-in hybrid vehicles are to be deployed broadly as replacements
for gasoline-powered vehicles. Although EES devices have been available
for many decades, there are many fundamental gaps in understanding the atomic-
and molecular-level processes that govern their operation, performance
limitations, and failure. Fundamental research is critically needed to uncover
the underlying principles that govern these complex and interrelated processes.
With a full understanding of these processes, new concepts can be formulated for
addressing present EES technology gaps and meeting future energy storage
requirements.
BES worked closely with the DOE Office of Energy Efficiency and Renewable Energy
and the DOE Office of Electricity Delivery and Energy Reliability to clearly
define future requirements for EES from the perspective of applications relevant
to transportation and electricity distribution, respectively, and to identify
critical technology gaps. In addition, leaders in EES industrial and
applied research laboratories were recruited to prepare a technology resource
document, Technology and Applied R&D Needs for Electrical Energy Storage,
which provided the groundwork for and served as a basis to inform the
deliberation of basic research discussions for the workshop attendees. The
invited workshop attendees, numbering more than 130, included representatives
from universities, national laboratories, and industry, including a significant
number of scientists from Japan and Europe. A plenary session at the
beginning of the workshop captured the present state of the art in research and
development and technology needs required for EES for the future. The
workshop participants were asked to identify key priority research directions
that hold particular promise for providing needed advances that will, in turn,
revolutionize the performance of EES. Participants were divided between
two panels focusing on the major types of EES, chemical energy storage and
capacitive energy storage. A third panel focused on cross-cutting research
that will be critical to achieving the technical breakthroughs required to meet
future EES needs. A closing plenary session summarized the most urgent
research needs that were identified for both chemical and capacitive energy
storage. The research directions identified by the panelists are presented in
this report in three sections corresponding to the findings of the three
workshop panels.
The panel on chemical energy storage acknowledged that progressing to the higher
energy and power densities required for future batteries will push materials to
the edge of stability; yet these devices must be safe and reliable through
thousands of rapid charge-discharge cycles. A major challenge for chemical
energy storage is developing the ability to store more energy while maintaining
stable electrode-electrolyte interfaces. The need to mitigate the volume
and structural changes to the active electrode sites accompanying the
charge-discharge cycle encourages exploration of nanoscale structures.
Recent developments in nanostructured and multifunctional materials were singled
out as having the potential to dramatically increase energy capacity and power
densities. However, an understanding of nanoscale phenomena is needed to
take full advantage of the unique chemistry and physics that can occur at the
nanoscale. Further, there is an urgent need to develop a fundamental
understanding of the interdependence of the electrolyte and electrode materials,
especially with respect to controlling charge transfer from the electrode to the
electrolyte. Combining the power of new computational capabilities and in
situ analytical tools could open up entirely new avenues for designing novel
multifunctional nanomaterials with the desired physical and chemical properties,
leading to greatly enhanced performance.
The panel on capacitive storage recognized that, in general, ECs have higher
power densities than batteries, as well as sub-second response times.
However, energy storage densities are currently lower than they are for
batteries and are insufficient for many applications. As with batteries, the
need for higher energy densities requires new materials. Similarly,
advances in electrolytes are needed to increase voltage and conductivity while
ensuring stability. Understanding how materials store and transport charge
at electrode-electrolyte interfaces is critically important and will require a
fundamental understanding of charge transfer and transport mechanisms. The
capability to synthesize nanostructured electrodes with tailored,
high-surface-area architectures offers the potential for storing multiple
charges at a single site, increasing charge density. The addition of
surface functionalities could also contribute to high and reproducible charge
storage capabilities, as well as rapid charge-discharge functions. The
design of new materials with tailored architectures optimized for effective
capacitive charge storage will be catalyzed by new computational and analytical
tools that can provide the needed foundation for the rational design of these
multifunctional materials. These tools will also provide the
molecular-level insights required to establish the physical and chemical
criteria for attaining higher voltages, higher ionic conductivity, and wide
electrochemical and thermal stability in electrolytes.
The third panel identified four cross-cutting research directions that were
considered to be critical for meeting future technology needs in EES:
1. Advances in Characterization
2. Nanostructured Materials
3. Innovations in Electrolytes
4. Theory, Modeling, and
Simulation
Exceptional insight into the physical and chemical phenomena that underlie the
operation of energy storage devices can be afforded by a new generation of
analytical tools. This information will catalyze the development of new
materials and processes required for future EES systems. New in situ
photon- and particle-based microscopic, spectroscopic, and scattering techniques
with time resolution down to the femtosecond range and spatial resolution
spanning the atomic and mesoscopic scales are needed to meet the challenge of
developing future EES systems. These measurements are critical to
achieving the ability to design EES systems rationally, including materials and
novel architectures that exhibit optimal performance. This information
will help identify the underlying reasons behind failure modes and afford
directions for mitigating them.
The performance of energy storage systems is limited by the performance of the
constituent materials—including active materials, conductors, and inert
additives. Recent research suggests that synthetic control of material
architectures (including pore size, structure, and composition; particle size
and composition; and electrode structure down to nanoscale dimensions) could
lead to transformational breakthroughs in key energy storage parameters such as
capacity, power, charge-discharge rates, and lifetimes. Investigation of model
systems of irreducible complexity will require the close coupling of theory and
experiment in conjunction with well-defined structures to elucidate fundamental
materials properties. Novel approaches are needed to develop multifunctional
materials that are self-healing, self-regulating, failure-tolerant,
impurity-sequestering, and sustainable. Advances in nanoscience offer
particularly exciting possibilities for the development of revolutionary
three-dimensional architectures that simultaneously optimize ion and electron
transport and capacity.
The design of EES systems with long cycle lifetimes and high energy-storage
capacities will require a fundamental understanding of charge transfer and
transport processes. The interfaces of electrodes with electrolytes are
astonishingly complex and dynamic. The dynamic structures of interfaces
need to be characterized so that the paths of electrons and attendant
trafficking of ions may be directed with exquisite fidelity. New
capabilities are needed to “observe” the dynamic composition and structure at an
electrode surface, in real time, during charge transport and transfer processes.
With this underpinning knowledge, wholly new concepts in materials design can be
developed for producing materials that are capable of storing higher energy
densities and have long cycle lifetimes.
A characteristic common to chemical and capacitive energy storage devices is
that the electrolyte transfers ions/charge between electrodes during charge and
discharge cycles. An ideal electrolyte provides high conductivity over a
broad temperature range, is chemically and electrochemically inert at the
electrode, and is inherently safe. Too often the electrolyte is the weak
link in the energy storage system, limiting both performance and reliability of
EES. At present, the myriad interactions that occur in electrolyte
systems—ion-ion, ion-solvent, and ion-electrode—are poorly understood.
Fundamental research will provide the knowledge that will permit the formulation
of novel designed electrolytes, such as ionic liquids and nanocomposite polymer
electrolytes, that will enhance the performance and lifetimes of electrolytes.
Advances in fundamental theoretical methodologies and computer technologies
provide an unparalleled opportunity for understanding the complexities of
processes and materials needed to make the groundbreaking discoveries that will
lead to the next generation of EES. Theory, modeling, and simulation can
effectively complement experimental efforts and can provide insight into
mechanisms, predict trends, identify new materials, and guide experiments.
Large multiscale computations that integrate methods at different time and
length scales have the potential to provide a fundamental understanding of
processes such as phase transitions in electrode materials, ion transport in
electrolytes, charge transfer at interfaces, and electronic transport in
electrodes.
Revolutionary breakthroughs in EES have been singled out as perhaps the most
crucial need for this nation’s secure energy future. The BES Workshop on
Basic Research Needs for Electrical Energy Storage concluded that the
breakthroughs required for tomorrow’s energy storage needs will not be realized
with incremental evolutionary improvements in existing technologies.
Rather, they will be realized only with fundamental research to understand the
underlying processes involved in EES, which will in turn enable the development
of novel EES concepts that incorporate revolutionary new materials and chemical
processes. Recent advances have provided the ability to synthesize novel
nanoscale materials with architectures tailored for specific performance; to
characterize materials and dynamic chemical processes at the atomic and
molecular level; and to simulate and predict structural and functional
relationships using modern computational tools. Together, these new
capabilities provide unprecedented potential for addressing technology and
performance gaps in EES devices.(List of recent BES workshop reports)
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Basic
Research Needs for Geosciences: Facilitating 21st Century Energy Systems
This report is based on a
BES Workshop on Basic Research Needs for Geosciences: Facilitating 21st Century
Energy Systems, February 21–23, 2007, to identify research areas in geosciences,
such as behavior of multiphase fluid-solid systems on a variety of scales,
chemical migration processes in geologic media, characterization of geologic
systems, and modeling and simulation of geologic systems, needed for improved
energy systems.
Serious challenges must be
faced in this century as the world seeks to meet global energy needs and at the
same time reduce emissions of greenhouse gases to the atmosphere. Even with a
growing energy supply from alternative sources, fossil carbon resources will
remain in heavy use and will generate large volumes of carbon dioxide (CO2).
To reduce the atmospheric impact of this fossil energy use, it is necessary to
capture and sequester a substantial fraction of the produced CO2.
Subsurface geologic formations offer a potential location for long-term storage
of the requisite large volumes of CO2. Nuclear energy resources could
also reduce use of carbon-based fuels and CO2 generation, especially
if nuclear energy capacity is greatly increased. Nuclear power generation
results in spent nuclear fuel and other radioactive materials that also must be
sequestered underground. Hence, regardless of technology choices, there will be
major increases in the demand to store materials underground in large
quantities, for long times, and with increasing efficiency and safety margins.
Rock formations are composed of complex natural materials and were not designed
by nature as storage vaults. If new energy technologies are to be developed in a
timely fashion while ensuring public safety, fundamental improvements are needed
in our understanding of how these rock formations will perform as storage
systems.
This report describes the scientific challenges associated with geologic
sequestration of large volumes of carbon dioxide for hundreds of years, and also
addresses the geoscientific aspects of safely storing nuclear waste materials
for thousands to hundreds of thousands of years. The fundamental crosscutting
challenge is to understand the properties and processes associated with complex
and heterogeneous subsurface mineral assemblages comprising porous rock
formations, and the equally complex fluids that may reside within and flow
through those formations. The relevant physical and chemical interactions occur
on spatial scales that range from those of atoms, molecules, and mineral
surfaces, up to tens of kilometers, and time scales that range from picoseconds
to millennia and longer. To predict with confidence the transport and fate of
either CO2
or the various components of stored nuclear materials, we need to learn to
better describe fundamental atomic, molecular, and biological processes, and to
translate those microscale descriptions into macroscopic properties of materials
and fluids. We also need fundamental advances in the ability to simulate
multiscale systems as they are perturbed during sequestration activities and for
very long times afterward, and to monitor those systems in real time with
increasing spatial and temporal resolution. The ultimate objective is to predict
accurately the performance of the subsurface fluid-rock storage systems, and to
verify enough of the predicted performance with direct observations to build
confidence that the systems will meet their design targets as well as
environmental protection goals.
The report summarizes the results and conclusions of a Workshop on Basic
Research Needs for Geosciences held in February 2007. Five panels met, resulting
in four Panel Reports, three Grand Challenges, six Priority Research Directions,
and three Crosscutting Research Issues. The Grand Challenges differ from the
Priority Research Directions in that the former describe broader, long-term
objectives while the latter are more focused.
GRAND CHALLENGES
Computational thermodynamics of complex fluids and solids. Predictions of
geochemical transport in natural materials must start with detailed knowledge of
the chemical properties of multicomponent fluids and solids. New modeling
strategies for geochemical systems based on first-principles methods are
required, as well as reliable tools for translating atomic-and molecular-scale
descriptions to the many orders of magnitude larger scales of subsurface
geologic systems. Specific challenges include calculation of equilibrium
constants and kinetics of heterogeneous reactions, descriptions of adsorption
and other mineral surface processes, properties of transuranic elements and
compounds, and mixing and transport properties for multicomponent liquid, solid
and supercritical solutions. Significant advances are required in calculations
based on the electronic Schrödinger equation, scaling of solution methods, and
representation in terms of Equations of State. Calibration of models with a new
generation of experiments will be critical.
Integrated characterization, modeling, and monitoring of geologic systems.
Characterization of the subsurface is inextricably linked to the modeling and
monitoring of processes occurring there. More accurate descriptions of the
behavior of subsurface storage systems will require that the diverse,
independent approaches currently used for characterizing, modeling and
monitoring be linked in a revolutionary and comprehensive way and carried out
simultaneously. The challenges arise from the inaccessibility and complexity of
the subsurface, the wide range of scales of variability, and the potential role
of coupled nonlinear processes. Progress in subsurface simulation requires
advances in the application of geological process knowledge for determining
model structure and the effective integration of geochemical and high-resolution
geophysical measurements into model development and parameterization. To fully
integrate characterization and modeling will require advances in methods for
joint inversion of coupled process models that effectively represent
nonlinearities, scale effects, and uncertainties.
Simulation of multiscale geologic systems for ultra-long times.
Anthropogenic perturbations of subsurface storage systems will occur over
decades, but predictions of storage performance will be needed that span
hundreds to many thousands of years, time scales that reach far beyond standard
engineering practice. Achieving this simulation capability requires a major
advance in modeling capability that will accurately couple information across
scales, i.e., account for the effects of small-scale processes on larger scales,
and the effects of fast processes as well as the ultra-slow evolution on long
time scales. Cross-scale modeling of complex dynamic subsurface systems requires
the development of new computational and numerical methods of stochastic
systems, new multiscale formulations, data integration, improvements in inverse
theory, and new methods for optimization.
PRIORITY RESEARCH DIRECTIONS
Mineral-water interface complexity and dynamics. Natural materials are
structurally complex, with variable composition, roughness, defect content, and
organic and mineral coatings. There is an overarching need to interrogate the
complex structure and dynamics at mineral-water interfaces with increasing
spatial and temporal resolution using existing and emerging experimental and
computational approaches. The fundamental objectives are to translate a
molecular-scale description of complex mineral surfaces to thermodynamic
quantities for the purpose of linking with macroscopic models, to follow
interfacial reactions in real time, and to understand how minerals grow and
dissolve and how the mechanisms couple dynamically to changes at the interface.
Nanoparticulate and colloid chemistry and physics. Colloidal particles
play critical roles in dispersion of contaminants from energy production, use,
or waste isolation sites. New advances are needed in characterization of
colloids, sampling technologies, and conceptual models for reactivity, fate, and
transport of colloidal particles in aqueous environments. Specific advances will
be needed in experimental techniques to characterize colloids at the atomic
level and to build quantitative models of their properties and reactivity.
Dynamic imaging of flow and transport. Improved imaging in the subsurface
is needed to allow in situ multiscale measurement of state variables as well as
flow, transport, fluid age, and reaction rates. Specific research needs include
development of smart tracers, identification of environmental tracers that would
allow age dating fluids in the 50–3000 year range, methods for measuring state
variables such as pressure and temperature continuously in space and time, and
better models for the interactions of physical fields, elastic waves, or
electromagnetic perturbations with fluid-filled porous media.
Transport properties and in situ characterization of fluid trapping,
isolation, and immobilization. Mechanisms of immobilization of injected CO2
include buoyancy trapping of fluids by geologic seals, capillary trapping of
fluid phases as isolated bubbles within rock pores, and sorption of CO2
or radionuclides on solid surfaces. Specific advances will be needed in our
ability to understand and represent the interplay of interfacial tension,
surface properties, buoyancy, the state of stress, and rock heterogeneity in the
subsurface.
Fluid-induced rock deformation. CO2
injection affects the thermal, mechanical, hydrological, and chemical state of
large volumes of the subsurface. Accurate forecasting of the effects requires
improved understanding of the coupled stress-strain and flow response to
injection-induced pressure and hydrologic perturbations in multiphase-fluid
saturated systems. Such effects manifest themselves as changes in rock
properties at the centimeter scale, mechanical deformation at meter-to-kilometer
scales, and modified regional fluid flow at scales up to 100 km. Predicting the
hydromechanical properties of rocks over this scale range requires improved
models for the coupling of chemical, mechanical, and hydrological effects. Such
models could revolutionize our ability to understand shallow crustal deformation
related to many other natural processes and engineering applications.
Biogeochemistry in extreme subsurface environments. Microorganisms
strongly influence the mineralogy and chemistry of geologic systems. CO2
and nuclear material isolation will perturb the environments for these
microorganisms significantly. Major advances are needed to describe how
populations of microbes will respond to the extreme environments of temperature,
pH, radiation, and chemistry that will be created, so that a much clearer
picture of biogenic products, potential for corrosion, and transport or
immobilization of contaminants can be assembled.
CROSSCUTTING RESEARCH ISSUES
The microscopic basis of macroscopic complexity. Classical continuum
mechanics relies on the assumption of a separation between the length scales of
microscopic fluctuations and macroscopic motions. However, in geologic problems
this scale separation often does not exist. There are instead fluctuations at
all scales, and the resulting macroscopic behavior can then be quite complex.
The essential need is to develop a scientific basis of “emergent” phenomena
based on the microscopic phenomena.
Highly reactive subsurface materials and environments. The emplacement of
energy system byproducts into geological repositories perturbs temperature and
pressure, imposes chemical gradients, creates intense radiation fields, and can
cause reactions that alter the minerals, pore fluids, and emplaced materials.
Strong interactions between the geochemical environment and emplaced materials
are expected. New insight is needed on equilibria in compositionally complex
systems, reaction kinetics in concentrated aqueous and other solutions, reaction
kinetics under near-equilibrium undersaturated and supersaturated conditions,
and transient reaction kinetics.
Thermodynamics of the solute-to-solid continuum. Reactions involving
solutes, colloids, particles, and surfaces control the transport of chemical
constituents in the subsurface environment. A rigorous structural, kinetic, and
thermodynamic description of the complex chemical reality between the molecular
and the macroscopic scale is a fundamental scientific challenge. Advanced
techniques are needed for characterizing particles in the nanometer-tomicrometer
size range, combined with a new description of chemical thermodynamics that does
not rely on a sharp distinction between solutes and solids.
TECHNICAL AND SCIENTIFIC IMPACT
The Grand Challenges, Priority Research Directions, and Crosscutting Issues
described in this report define a science-based approach to understanding the
long-term behavior of subsurface geologic systems in which anthropogenic CO2
and nuclear materials could be stored. The research areas are rich with
opportunities to build fundamental knowledge of the physics, chemistry, and
materials science of geologic systems that will have impacts well beyond the
specific applications. The proposed research is based on development of a new
level of understanding—physical, chemical, biological, mathematical, and
computational—of processes that happen at the microscopic scale of atoms,
molecules and mineral surfaces, and how those processes translate to material
behavior over large length scales and on ultra-long time scales. Addressing the
basic science issues described would revolutionize our ability to understand,
simulate, and monitor all of the subsurface settings in which transport is
critical, including the movement of contaminants, the emplacement of minerals,
or the management of aquifers. The results of the research will have a wide
range of implications from physics and chemistry, to material science, biology
and earth science.
(List of recent BES workshop reports)
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Basic
Research Needs for Clean and Efficient Combustion
of 21st Century Transportation Fuels
This report is based on a BES Workshop on
Clean and Efficient Combustion of 21st Century Transportation Fuels, October
29–November 1, 2006, to identify basic research
needs and opportunities underlying utilization of evolving transportation fuels,
with a focus on new or emerging science challenges that have the potential for
significant long-term impact on fuel efficiency and emissions.
From the invention of the
wheel, advances in transportation have increased the mobility of human kind,
enhancing the quality of life and altering our very perception of time and
distance. Early carts and wagons driven by human or animal power allowed the
movement of people and goods in quantities previously thought impossible. With
the rise of steam power, propeller driven ships and railroad locomotives shrank
the world as never before. Ocean crossings were no longer at the whim of the
winds, and continental crossings went from grand adventures to routine,
scheduled outings. The commercialization of the internal combustion engine at
the turn of the twentieth century brought about a new, and very personal,
revolution in transportation, particularly in the United States. Automobiles
created an unbelievable freedom of movement: A single person could travel to any
point in the county in a matter of days, on a schedule of his or her own
choosing. Suburbs were built on the promise of cheap, reliable, personal
transportation. American industry grew to depend on internal combustion engines
to produce and transport goods, and farmers increased yields and efficiency by
employing farm machinery. Airplanes, powered by internal combustion engines,
shrank the world to the point where a trip between almost any two points on the
globe is now measured not in days or months, but in hours.
Transportation is the second largest consumer of energy in the United States,
accounting for nearly 60% of our nation’s use of petroleum, an amount equivalent
to all of the oil imported into the U.S. The numbers are staggering—the
transport of people and goods within the U.S. burns almost one million gallons
of petroleum each minute of the day. Our Founding Fathers may not have foreseen
freedom of movement as an inalienable right, but Americans now view it as such.
Knowledge
is power, a maxim that is literally true for combustion. In our global,
just-in-time economy, American competitiveness and innovation require an
affordable, diverse, stable, and environmentally acceptable energy supply.
Currently 85% of our nation’s energy comes from
hydrocarbon sources, including natural gas, petroleum, and coal; 97% of
transportation energy derives from petroleum, essentially all from combustion in
gasoline engines (65%), diesel engines (20%), and jet turbines (12%). The
monolithic nature of transportation technologies offers the opportunity for
improvements in efficiency of 25-50% through strategic technical investment in
advanced fuel/engine concepts and devices. This investment is not a matter of
choice, but, an economic, geopolitical, and environmental necessity. The reality
is that the internal combustion engine will remain the primary driver of
transport for the next 30-50 years, whether or not one believes that the peak in
oil is past or imminent, or that hydrogen-fueled and electric vehicles will
power transport in the future, or that geopolitical tensions will ease through
international cooperation. Rational evaluation of U.S. energy security must
include careful examination of how we achieve optimally efficient and clean
combustion of precious transportation fuels in the 21st century.
The
Basic Energy Sciences Workshop on Clean and Efficient Combustion of 21st
Century Transportation Fuels
Our
historic dependence on light, sweet crude oil for our transportation fuels will
draw to a close over the coming decades as finite resources are exhausted. New
fuel sources, with differing characteristics, are emerging to displace crude
oil. As these new fuel streams enter the market, a series of new engine
technologies are also under development, promising improved efficiency and
cleaner combustion. To date, however, a coordinated strategic effort to match
future fuels with evolving engines is lacking.
To provide
the scientific foundation to enable technology breakthroughs in transportation
fuel utilization, the Office of Basic Energy Sciences in the U.S. Department of
Energy (DOE) convened the Workshop on Basic Research Needs for Clean and
Efficient Combustion of 21st Century Transportation Fuels from
October 30 to November 1, 2006. This report is a summary of that Workshop. It
reflects the collective output of the Workshop participants, which included over
80 leading scientists and engineers representing academia, industry, and
national laboratories in the United States and Europe. Researchers specializing
in basic science and technological applications were well represented, producing
a stimulating and engaging forum. Workshop planning and execution involved
advance coordination with DOE Office of Energy Efficiency and Renewable Energy,
FreedomCAR and Vehicle Technologies, which manages applied research and
development of transportation technologies.
Priority
research directions were identified by three panels, each made up of a subset of
the Workshop attendees and interested observers. The first two panels were
differentiated by their focus on engines or fuels and were similar in their
strategy of working backward from technology drivers to scientific research
needs. The first panel focused on Novel Combustion, as embodied in promising
new engine technologies. The second panel focused on Fuel Utilization, inspired
by the unique (and largely unknown) challenges of the emerging fuel streams
entering the market. The third panel explored crosscutting science themes and
identified general gaps in our scientific understanding of 21st-century
fuel combustion. Subsequent to the Workshop, co-chairs and panel leads distilled
the collective output to produce eight distinct, targeted research areas that
advance one overarching grand challenge: to develop a validated, predictive,
multi-scale, combustion modeling capability to optimize the design and operation
of evolving fuels in advanced engines for transportation applications.
Fuels and Engines
Transportation
fuels for automobile, truck and aircraft engines are currently produced by
refining petroleum-based sweet crude oil, from which gasoline, diesel fuel and
jet fuel are each made with specific physical and chemical characteristics
dictated by the type of engine in which they are to be burned. Standardized fuel
properties and restricted engine operating domains couple to provide reliable
performance. As new fuels derived from oil sands, oil shale, coal, and bio-feedstocks
emerge as replacements for light, sweet crude oil, both uncertainties and
strategic opportunities arise. Rather than pursue energy-intensive refining of
these qualitatively different emerging fuels to match current fuel formulations,
we must strive to achieve a “dual revolution” by interdependently advancing both
fuel and engine technologies. Spark-ignited gasoline engines equipped with
catalytic after-treatment operate cleanly but well below optimal efficiency due
to low compression
ratios and throttle-plate losses used to control air intake. Diesel engines
operate more efficiently at higher compression ratios but sample broad realms of
fuel/air ratio, thereby producing soot and NOx for which burnout
and/or removal can prove problematic. A number of new engine technologies are
attempting to overcome these efficiency and emissions compromises. Direct
injection gasoline engines operate without throttle plates, increasing
efficiency, while retaining the use of a catalytic converter. Ultra-lean,
high-pressure, low-temperature diesel combustion seeks to avoid the conditions
that form pollutants, while maintaining very high efficiency. A new form of
combustion, homogeneous charge compression ignition (HCCI) seeks to combine the
best of diesel and gasoline engines. HCCI employs a premixed fuel-air charge
that is ignited by compression, with the ignition timing controlled by
in-cylinder fuel chemistry. Each of these advanced combustion strategies must
permit and even exploit fuel flexibility as the 21st-century fuel
stream matures. The opportunity presented by new fuel sources and advanced
engine concepts offers such an overwhelming design and operation parameter space
that only those technologies that build upon a predictive science capability
will likely mature to a product within a useful timeframe.
Research Directions
The
Workshop identified a single, overarching grand challenge: The development of
a validated, predictive, multi-scale, combustion modeling capability to optimize
the design and operation of evolving fuels in advanced engines for
transportation applications. A broad array of discovery research and
scientific inquiry that integrates experiment, theory, modeling and simulation
will be required. This predictive capability, if attained, will change
fundamentally the process for fuels research and engine development by
establishing a scientific understanding of sufficient depth and flexibility to
facilitate realistic simulation of fuel combustion in existing and proposed
engines. Similar understanding in aeronautics has produced the beautiful and
efficient complex curves of modern aircraft wings. These designs could never
have been realized through cut-and-try engineering, but rather rely on the
prediction and optimization of complex air flows. An analogous experimentally
validated, predictive capability for combustion is a daunting challenge for
numerous reasons: (1) spatial scales of importance range from the dimensions of
the atom up to that of an engine piston; (2) the combustion chemistry of 21st-century
fuels is astonishingly complex with hundreds of different fuel molecules and
many thousands of possible reactions contributing to the oxidative release of
energy stored in chemical bonds—chemical details also dictate emissions
profiles, engine knock conditions and, for HCCI, ignition timing; (3) evolving
engine designs will operate under dilute conditions at very high pressures and
compression ratios—we possess neither sufficient concepts nor experimental
tools to address these new operating conditions; (4) turbulence, transport, and
radiative phenomena have a profound impact on local chemistry in most combustion
media but are poorly understood and extremely challenging to characterize; (5)
even assuming optimistic growth in computing power for existing and envisioned
architectures, combustion phenomena are and will remain too complex to simulate
in their complete detail, and methods that condense information and accurately
propagate uncertainties across length and time scales will be required to
optimize fuel/engine design and operation. Eight priority research directions,
each of which focuses on crucial elements of the overarching grand challenge,
are cited as most critical to the path forward by the Workshop participants.
In
addition to the unifying grand challenge and specific priority research
directions, the Workshop produced a keen sense of urgency and opportunity for
the development of revolutionary combustion technology for transportation based
upon fundamental combustion science. Internal combustion engines are often
viewed as mature technology, developed in an Edisonian fashion over a hundred
years. The participants at the Workshop were unanimous in their view that only
through the achievable goal of truly predictive combustion science will the
engines of the 21st century realize unparalleled efficiency and cleanliness in
the challenging environment of changing fuel streams.
(List of recent BES workshop reports)
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Basic
Research Needs for Advanced Nuclear Energy Systems
This report is based on a BES Workshop on
Advanced Nuclear Energy Systems, July 31–August 3, 2006,
to identify new, emerging, and scientifically challenging areas in materials and
chemical sciences that have the potential for significant impact on advanced
nuclear energy systems.
The global utilization of
nuclear energy has come a long way from its humble beginnings in the first
sustained nuclear reaction at the University of Chicago in 1942. Today, there
are over 440 nuclear reactors in 31 countries producing approximately 16% of the
electrical energy used worldwide. In the United States, 104 nuclear reactors
currently provide 19% of electrical energy used nationally. The International
Atomic Energy Agency projects significant growth in the utilization of nuclear
power over the next several decades due to increasing demand for energy and
environmental concerns related to emissions from fossil plants. There are 28 new
nuclear plants currently under construction including 10 in China, 8 in India,
and 4 in Russia. In the United States, there have been notifications to the
Nuclear Regulatory Commission of intentions to apply for combined construction
and operating licenses for 27 new units over the next decade.
The projected
growth in nuclear power has focused increasing attention on issues related to
the permanent disposal of nuclear waste, the proliferation of nuclear weapons
technologies and materials, and the sustainability of a once-through nuclear
fuel cycle. In addition, the effective utilization of nuclear power will require
continued improvements in nuclear technology, particularly related to safety and
efficiency. In all of these areas, the performance of materials and chemical
processes under extreme conditions is a limiting factor. The related basic
research challenges represent some of the most demanding tests of our
fundamental understanding of materials science and chemistry, and they provide
significant opportunities for advancing basic science with broad impacts for
nuclear reactor materials, fuels, waste forms, and separations techniques. Of
particular importance is the role that new nanoscale characterization and
computational tools can play in addressing these challenges. These tools, which
include DOE synchrotron X-ray sources, neutron sources, nanoscale science
research centers, and supercomputers, offer the opportunity to transform and
accelerate the fundamental materials and chemical sciences that underpin
technology development for advanced nuclear energy systems.
The fundamental
challenge is to understand and control chemical and physical phenomena in
multi-component systems from femto-seconds to millennia, at temperatures to
1000ºC, and for radiation doses to hundreds of displacements per atom (dpa).
This is a scientific challenge of enormous proportions, with broad implications
in the materials science and chemistry of complex systems. New understanding is
required for microstructural evolution and phase stability under relevant
chemical and physical conditions, chemistry and structural evolution at
interfaces, chemical behavior of actinide and fission-product solutions, and
nuclear and thermo-mechanical phenomena in fuels and waste forms.
First-principles approaches are needed to describe f-electron systems,
design molecules for separations, and explain materials failure mechanisms.
Nanoscale synthesis and characterization methods are needed to understand and
design materials and interfaces with radiation, temperature, and corrosion
resistance. Dynamical measurements are required to understand fundamental
physical and chemical phenomena. New multiscale approaches are needed to
integrate this knowledge into accurate models of relevant phenomena and complex
systems across multiple length and time scales.
Workshop
The Department of Energy (DOE) Workshop on Basic Research
Needs for Advanced Nuclear Energy Systems was convened in July 2006 to identify
new, emerging, and scientifically challenging areas in materials and chemical
sciences that have the potential for significant impact on advanced nuclear
energy systems. Sponsored by the DOE Office of Basic Energy Sciences (BES), the
workshop provided recommendations for priority research directions and
crosscutting research themes that underpin the development of advanced
materials, fuels, waste forms, and separations technologies for the effective
utilization of nuclear power. A total of 235 invited experts from
31 universities, 11 national laboratories, 6 industries, 3 government agencies,
and 11 foreign countries attended the workshop.
The workshop
was the sixth in a series of BES workshops focused on identifying basic research
needs to overcome short-term showstoppers and to formulate long-term grand
challenges related to energy technologies. These workshops have followed a
common format that includes the development of a technology perspectives
resource document prior to the workshop, a plenary session including invited
presentations from technology and research experts, and topical panels to
determine basic research needs and recommended research directions. Reports from
the workshops are available on the BES website at
http://www.sc.doe.gov/bes/reports/list.html.
The workshop
began with a plenary session of invited presentations from national and
international experts on science and technology related to nuclear energy. The
presentations included nuclear technology, industry, and international
perspectives, and an overview of the Global Nuclear Energy Partnership. Frontier
research presentations were given on relevant topics in materials science,
chemistry, and computer simulation. Following the plenary session, the workshop
divided into six panels: Materials under Extreme Conditions, Chemistry under
Extreme Conditions, Separations Science, Advanced Actinide Fuels, Advanced Waste
Forms, and Predictive Modeling and Simulation. In addition, there was a crosscut
panel that looked for areas of synergy across the six topical panels. The panels
were composed of basic research leaders in the relevant fields from
universities, national laboratories, and other institutions. In advance of the
workshop, panelists were provided with a technology perspectives resource
document that described the technology and applied R&D needs for advanced
nuclear energy systems. In addition, technology experts were assigned to each of
the panels to ensure that the basic research discussions were informed by a
current understanding of technology issues.
The panels were
charged with defining the state of the art in their topical research area,
describing the related basic research challenges that must be overcome to
provide breakthrough technology opportunities, and recommending basic research
directions to address these challenges. These basic research challenges and
recommended research directions were consolidated into Scientific Grand
Challenges, Priority Research Directions, and Crosscutting Research Themes.
These results are summarized below and described in detail in the full report.
Scientific Grand Challenges
Scientific
Grand Challenges represent barriers to fundamental understanding that, if
overcome, could transform the related scientific field. Historical examples of
scientific grand challenges
with
far-reaching scientific and technological impacts include the structure of DNA,
the understanding of quantum behavior, and the explanation of nuclear fission.
Theoretical breakthroughs and new experimental capabilities are often key to
addressing these challenges. In advanced nuclear energy systems, scientific
grand challenges focus on the fundamental materials and chemical sciences that
underpin the performance of materials and processes under extreme conditions of
radiation, temperature, and corrosive environments. Addressing these challenges
offers the potential of revolutionary new approaches to developing improved
materials and processes for nuclear applications. The workshop identified the
following three Scientific Grand Challenges.
Resolving the f-electron challenge to master the
chemistry and physics of actinides and actinide-bearing materials.
The introduction of new
actinide-based fuels for advanced nuclear energy systems requires new chemical
separations strategies and predictive understanding of fuel and waste-form
fabrication and performance. However, current computational electronic-structure
approaches are inadequate to describe the electronic behavior of actinide
materials, and the multiplicity of chemical forms and oxidation states for these
elements complicates their behavior in fuels, solutions, and waste forms.
Advances in density functional theory as well as in the treatment of
relativistic effects are needed in order to understand and predict the behavior
of these strongly correlated electron systems.
Developing a first-principles, multiscale description
of material properties in complex materials under extreme conditions.
The long-term stability and
mechanical integrity of structural materials, fuels, claddings, and waste forms
are governed by the kinetics of microstructure and interface evolution under the
combined influence of radiation, high temperature, and stress. Controlling the
mechanical and chemical properties of materials under these extreme conditions
will require the ability to relate phase stability and mechanical behavior to a
first-principles understanding of defect production, diffusion, trapping, and
interaction. New synthesis techniques based on the nanoscale design of materials
offer opportunities for mitigating the effects of radiation damage through the
development and control of nanostructured defect sinks. However, a unified,
predictive multiscale theory that couples all relevant time and length scales in
microstructure evolution and phase stability must be developed. In addition,
fundamental advances are needed in nanoscale characterization, diffusion,
thermodynamics, and in situ studies of fracture and deformation.
Understanding and designing new molecular systems to
gain unprecedented control of chemical selectivity during processing.
Advanced separations
technologies for nuclear fuel reprocessing will require unprecedented control of
chemical selectivity in complex environments. This control requires the ability
to design, synthesize, characterize, and simulate molecular systems that
selectively trap and release target molecules and ions with high efficiency
under extreme conditions and to understand how mesoscale phenomena such as
nanophase behavior and energetics in macromolecular systems impact partitioning.
New capabilities in molecular spectroscopy, imaging, and computational modeling
offer opportunities for breakthroughs in this area.
Priority Research Directions
Priority Research Directions are areas of basic research that
have the highest potential for impact in a specific research or technology area.
They represent opportunities that align with scientific grand challenges,
emerging research opportunities, and related technology priorities. The workshop
identified nine Priority Research Directions for basic research related to
advanced nuclear energy systems.
Nanoscale design of materials and interfaces that
radically extend performance limits in extreme radiation environments.
The fundamental
understanding of the interaction of defects with nanostructures offers the
potential for the design of materials and interfaces that mitigate radiation
damage by controlling defect behavior. New research is needed in the design,
synthesis, nanoscale characterization, and time-resolved study of nanostructured
materials and interfaces that offer the potential to control defect production,
trapping, and interaction under extreme conditions.
Physics and chemistry of actinide-bearing materials
and the f-electron challenge.
A robust theory of the electronic structure of actinides will
provide an improved understanding of their physical and chemical properties and
behavior, leading to opportunities for advances in fuels and waste forms. New
advances in exchange and correlation functionals in density functional theory as
well as in the treatment of relativistic effects and in software implementation
on advanced computer architectures are needed to overcome the challenges of
adequately treating the behavior of 4f and 5f electrons, namely,
strong correlation, spin-orbit coupling, and multiplet complexity, as well as
additional relativistic effects. Advances are needed in the application of these
new electronic structure methods for f-element-containing molecules and
solids to calculate the properties of defects in multi-component systems, and in
the fundamental understanding of related chemical and physical properties at
high temperature.
Microstructure and property stability under extreme
conditions. The
predictive understanding of microstructural evolution and property changes under
extreme conditions is essential for the rational design of materials for
structural, fuels, and waste-form applications. Advances are needed to develop a
first-principles understanding of the relationship of defect properties and
microstructural evolution to mechanical behavior and phase stability. This will
require a closely coupled approach of in situ studies of nanoscale and
mechanical behavior with multiscale theory.
Mastering actinide and fission product chemistry under
all chemical conditions.
A more accurate understanding of the electronic structure of
the complexes of actinide and fission products will expand our ability to
predict their behavior quantitatively under conditions relevant to all stages in
fuel reprocessing (separations, dissolution, and stabilization of waste forms)
and in new media that are proposed for advanced processing systems. This
knowledge must be supplemented by accurate prediction and manipulation of
solvent properties and chemical reactivities in non-traditional separation
systems such as modern “tunable” solvent systems. This will require
quantitative, fundamental understanding of the mechanisms of solvent tunability,
the factors limiting control over solvent properties, the forces driving
chemical speciation, and modes of controlling reactions. Basic research needs
include f-element electronic structure and bonding, speciation and
reactivity, thermodynamics, and solution behavior.
Exploiting organization to achieve selectivity at
multiple length scales. Harnessing the complexity of organization that occurs at the mesoscale
in solution or at interfaces will lead to new separation systems that provide
for greatly increased selectivity in the recovery of target species and reduced
formation of secondary waste streams through ligand degradation. Research
directions include design of ligands and other selectivity agents, expanding the
range of selection/release mechanisms, fundamental understanding of phase
phenomena and self-assembly in separations, and separations systems employing
aqueous solvents.
Adaptive material-environment interfaces for extreme
chemical conditions.
Chemistry at interfaces will
play a crucial role in the fabrication, performance, and stability of materials
in almost every aspect of Advanced Nuclear Energy Systems, from fuel, claddings,
and pressure vessels in reactors to fuel reprocessing and separations, and
ultimately to long-term waste storage. Revolutionary advances in the
understanding of interfacial chemistry of materials through developments in new
modeling and in situ experimental techniques offer the ability to design
material interfaces capable of providing dynamic, universal stability over a
wide range of conditions and with much greater “self-healing” capabilities.
Achieving the necessary scientific advances will require moving beyond
interfacial chemistry in ultra-high-vacuum environments to the development of in
situ techniques for monitoring the chemistry at fluid/solid and solid/solid
interfaces under conditions of high pressure and temperature and harsh chemical
environments.
Fundamental effects of radiation and radiolysis in
chemical processes.
The reprocessing of nuclear fuel and the storage of nuclear waste present
environments that include substantial radiation fields. A predictive
understanding of the chemical processes resulting from intense radiation, high
temperatures, and extremes of acidity and redox potential on chemical speciation
is required to enhance efficient, targeted separations processes and effective
storage of nuclear waste. In particular, the effect of radiation on the
chemistries of ligands, ionic liquids, polymers, and molten salts is poorly
understood. There is a need for an improved understanding of the fundamental
processes that affect the formation of radicals and ultimately control the
accumulation of radiation-induced damage to separation systems and waste forms.
Fundamental thermodynamics and kinetic processes in
multi-component systems for fuel fabrication and performance.
The fabrication and performance
of advanced nuclear fuels, particularly those containing the minor actinides, is
a significant challenge that requires a fundamental understanding of the
thermodynamics, transport, and chemical behavior of complex materials during
processing and irradiation. Global thermochemical models of complex phases that
are informed by ab initio calculations of materials properties and
high-throughput predictive models of complex transport and phase segregation
will be required for full fuel fabrication and performance calculations. These
models, when coupled with appropriate experimental efforts, will lead to
significantly improved fuel performance by creating novel tailored fuel forms.
Predictive multiscale modeling of materials and
chemical phenomena in multi-component systems under extreme conditions.
The advent of
large-scale (petaflop) simulations will significantly enhance the prospect of
probing important molecular-level mechanisms underlying the macroscopic
phenomena of solution
and interfacial chemistry in actinide-bearing systems and of materials and fuels
fabrication, performance, and failure under extreme conditions. There is an
urgent need to develop multiscale algorithms capable of efficiently treating
systems whose time evolution is controlled by activated processes and rare
events. Although satisfactory solutions are lacking, there are promising
directions, including accelerated molecular dynamics (MD) and adaptive kinetic
Monte Carlo methods, which should be pursued. Many fundamental problems in
advanced nuclear energy systems will benefit from multi-physics, multiscale
simulation methods that can span time scales from picoseconds to seconds and
longer, including fission product transport in nuclear fuels, the evolution of
microstructure of irradiated materials, the migration of radionuclides in
nuclear waste forms, and the behavior of complex separations media.
Crosscutting Research Themes
Crosscutting
Research Themes are research directions that transcend a specific research area
or discipline, providing a foundation for progress in fundamental science on a
broad front. These themes are typically interdisciplinary, leveraging results
from multiple fields and approaches to provide new insights and underpinning
understanding. Many of the fundamental science issues related to materials,
fuels, waste forms, and separations technologies have crosscutting themes and
synergies. The workshop identified four crosscutting basic research themes
related to materials and chemical processes for advanced nuclear energy systems:
Tailored nanostructures for radiation-resistant
functional and structural materials.
There is evidence that the design and control of specialized
nanostructures and defect complexes can create sinks for radiation-induced
defects and impurities, enabling the development of highly radiation-resistant
materials. New capabilities in the synthesis and characterization of materials
with controlled nanoscale structure offer opportunities for the development of
tailored nanostructures for structural applications, fuels, and waste forms.
This approach crosscuts advanced materials synthesis and processing, radiation
effects, nanoscale characterization, and simulation.
Solution and solid-state chemistry of 4f and 5f
electron systems.
Advances in the basic science of 4f and 5f electron systems in
materials and solutions offer the opportunity to extend condensed matter physics
and reaction chemistry on a broad front, including applications that impact the
development of nuclear fuels, waste forms, and separations technologies. This is
a key enabling science for the fundamental understanding of actinide-bearing
materials and solutions.
Physics and chemistry at interfaces and in confined
environments.
Controlling the structure and composition of interfaces is essential to ensuring
the long-term stability of reactor materials, fuels, and waste forms. The
fundamental understanding of interface science and related transport and
chemical phenomena in extreme environments crosscuts many science and technology
areas. New computational and nanoscale structure and dynamics measurement tools
offer significant opportunities for advancing interface science with broad
impacts on the predictive design of advanced materials and processes for nuclear
energy applications.
Physical and chemical complexity in multi-component
systems. Advanced
fuels, waste forms, and separations technologies are highly interactive,
multi-component systems. A fundamental understanding of these complex systems
and related structural and phase stability and chemical reactivity under extreme
conditions is needed to develop and predict the performance of materials and
separations processes in advanced nuclear energy systems. This is a challenging
problem in complexity with broad implications across science and technology.
Taken together,
these Scientific Grand Challenges, Priority Research Directions, and
Crosscutting Research Themes define the landscape for a science-based approach
to the development of materials and chemical processes for advanced nuclear
energy systems. Building upon new experimental tools and computational
capabilities, they presage a renaissance in fundamental science that underpins
the development of materials, fuels, waste forms, and separations technologies
for nuclear energy applications. Addressing these basic research needs offers
the potential to revolutionize the science and technology of advanced nuclear
energy systems by enabling new materials, processes, and predictive modeling,
with resulting improvements in performance and reduction in development times.
The fundamental research outlined in this report offers an outstanding
opportunity to advance the materials, chemical, and computational science of
complex systems at multiple length and time scales, furthering both fundamental
understanding and the technology of advanced nuclear energy systems.
(List of recent BES workshop reports)
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Basic
Research Needs for Solid-State Lighting
This report is based on a BES Workshop on Solid-State
Lighting (SSL), May 22–24, 2006, to examine
the gap separating current state-of-the-art SSL technology from an energy
efficient, high-quality, and economical SSL technology suitable for general
illumination; and to identify the most significant fundamental scientific
challenges and research directions that would enable that gap to be bridged.
Since fire was first harnessed, artificial lighting has gradually
broadened the horizons of human civilization. Each new advance in lighting
technology, from fat-burning lamps to candles to gas lamps to the incandescent
lamp, has extended our daily work and leisure further past the boundaries of
sunlit times and spaces. The incandescent lamp did this so dramatically after
its invention in the 1870s that the light bulb became the very symbol of a “good
idea.”
Today, modern civilization as we know it could not function without artificial
lighting; artificial lighting is so seamlessly integrated into our daily lives
that we tend not to notice it until the lights go out. Our dependence is even
enshrined in daily language: an interruption of the electricity supply is
commonly called a “blackout.”
This ubiquitous resource, however, uses an enormous amount of energy. In
2001, 22% of the nation’s electricity, equivalent to 8% of the nation’s total
energy, was used for artificial light. The cost of this energy to the consumer
was roughly $50 billion per year or approximately $200 per year for every person
living in the U.S. The cost of this energy to the environment was approximately
130 million tons of carbon emitted into our atmosphere, or about 7% of all the
carbon emitted by the U.S. Our increasingly precious energy resources and the
growing threat of climate change demand that we reduce the energy and
environmental cost of artificial lighting, an essential and pervasive staple of
modern life.
There is ample room for reducing this energy and environmental cost. The
artificial lighting we take for granted is extremely inefficient primarily
because all these technologies generate light as a by-product of indirect
processes producing heat or plasmas. Incandescent lamps (a heated wire in a
vacuum bulb) convert only about 5% of the energy they consume into visible
light, with the rest emerging as heat. Fluorescent lamps (a phosphor-coated gas
discharge tube, invented in the 1930s) achieve a conversion efficiency of only
about 20%. These low efficiencies contrast starkly with the relatively high
efficiencies of other common building technologies: heating is typically 70%
efficient, and electric motors are typically 85 to 95% efficient. About 1.5
billion light bulbs are sold each year in the U.S. today, each one an engine for
converting the earth’s precious energy resources mostly into waste heat,
pollution, and greenhouse gases.
SOLID-STATE LIGHTING
There is no physical reason why a 21st century lighting technology should not be
vastly more efficient, thereby reducing equally vastly our energy consumption.
If a 50%-efficient technology were to exist and be extensively adopted, it would
reduce energy consumption in the U.S. by about 620 billion kilowatt-hours per
year by the year 2025 and eliminate the need for about 70 nuclear plants, each
generating a billion Watts of power.
Solid-state lighting (SSL) is the direct conversion of electricity to visible
white light using semiconductor materials and has the potential to be just such
an energy-efficient lighting technology. By avoiding the indirect processes
(producing heat or plasmas) characteristic of traditional incandescent and
fluorescent lighting, it can work at a far higher efficiency, “taking the heat
out of lighting,” it might be said. Recently, for example, semiconductor devices
emitting infrared light have demonstrated an efficiency of 76%. There is no
known fundamental physical barrier to achieving similar (or even higher)
efficiencies for visible white light, perhaps approaching 100% efficiency.
Despite this tantalizing potential, however, SSL suitable for illumination today
has an efficiency that falls short of a perfect 100% by a factor of fifteen.
Partly because of this inefficiency, the purchase cost of SSL is too high for
the average consumer by a factor ten to a hundred, and SSL suitable for
illumination today has a cost of ownership twenty times higher than that
expected for a 100% efficient light source.
The reason is that SSL is a dauntingly demanding technology. To generate light
near the theoretical efficiency limit, essentially every electron injected into
the material must result in a photon emitted from the device. Furthermore, the
voltage required to inject and transport the electrons to the light-emitting
region of the device must be no more than that corresponding to the energy of
the resulting photon. It is insufficient to generate “simple” white light; the
distribution of photon wavelengths must match the spectrum perceived by the
human eye to render colors accurately, with no emitted photons outside the
visible range. Finally, all of these constraints must be achieved in a single
device with an operating lifetime of at least a thousand hours (and preferably
ten to fifty times longer), at an ownership cost-of-light comparable to, or
lower than, that of existing lighting technology.
Where promising demonstrations of higher efficiency exist, they are typically
achieved in small devices (to enhance light extraction), at low brightness (to
minimize losses) or with low color-rendering quality (overemphasizing yellow and
green light, to which the eye is most sensitive). These restrictions lead to a
high cost of ownership for high-quality light that would prevent the widespread
acceptance of SSL. For example, Cree Research recently (June 2006) demonstrated
a 131 lm/W white light device, which translates roughly to 35% efficiency but
with relatively low lumen output. With all devices demonstrated to date, a very
large gap is apparent between what is achievable today and the 100% (or roughly
375 lm/W) efficiency that should be possible with SSL.
Today, we cannot produce white SSL that is simultaneously high in efficiency,
low in cost, and high in color-rendering quality. In fact, we cannot get within
a factor of ten in either efficiency or cost. Doing so in the foreseeable future
will require breakthroughs in technology, stimulated by a fundamental
understanding of the science of light-emitting materials.
THE BASIC ENERGY SCIENCES WORKSHOP ON SOLID-STATE LIGHTING
To accelerate the laying of the scientific foundation that would enable such
technology breakthroughs, the Office of Basic Energy Sciences in the U.S.
Department of Energy (DOE) convened the Workshop on Basic Energy Needs for
Solid-State Lighting from May 22 to 24, 2006. This report is a summary of
that workshop. It reflects the collective output of the workshop attendees,
which included 80 scientists representing academia, national laboratories, and
industry in the United States, Europe, and Asia. Workshop planning and execution
involved advance coordination with the DOE Office of Energy Efficiency and
Renewable Energy, Building Technologies program, which manages applied research
and development of SSL technologies and the Next Generation Lighting Initiative.
The Workshop identified two Grand Challenges, seven Priority Research
Directions, and five Cross-Cutting Research Directions. These represent the most
specific outputs of the workshop.
GRAND CHALLENGES
The Grand Challenges are broad areas of discovery research and scientific
inquiry that will lay the groundwork for the future of SSL. The first Grand
Challenge aims to change the very paradigm by which SSL structures are
designed—moving from serendipitous discovery towards rational design. The second
Grand Challenge aims to understand and control the essential roadblock to SSL—the
microscopic pathways through which losses occur as electrons produce light.
Rational Design of SSL Structures. Many materials must be combined
in order to form a light-emitting device, each individual material working in
concert with the others to control the flow of electrons so that all their
energy produces light. Today, novel light-emitting and charge-transporting
materials tend to be discovered rather than designed “with the end in mind.” To
approach 100% efficiency, fundamental building blocks should be designed so they
work together seamlessly, but such a design process will require much greater
insight than we currently possess. Hence, our aim is to understand
light-emitting organic and inorganic (and hybrid) materials and nanostructures
at a fundamental level to enable the rational design of low-cost,
high-color-quality, near-100% efficient SSL structures from the ground up. The
anticipated results are tools for rational, informed exploration of technology
possibilities; and insights that open the door to as-yet-unimagined ways of
creating and using artificial light.
Controlling Losses in the Light-Emission Process. The key to high
efficiency SSL is using electrons to produce light but not heat. That this does
not occur in today’s SSL structures stems from the abundance of decay pathways
that compete with light emission for electronic excitations in semiconductors.
Hence, our aim is to discover and control the materials and nanostructure
properties that mediate the competing conversion of electrons to light and heat,
enabling the conversion of every injected electron into useful photons. The
anticipated results are ultra-high-efficiency light-emitting materials and
nanostructures, and a deep scientific understanding of how light interacts with
matter, with broad impact on science and technology areas beyond SSL.
RESEARCH DIRECTIONS
The Priority and Cross-Cutting Research Directions are narrower areas of
discovery research and use-inspired basic research targeted at a particular
materials set or at a particular area of scientific inquiry believed to be
central to one or more roadblocks in the path towards future SSL technology.
These Research Directions also support one or both Grand Challenges.
The Research Directions were identified by three panels, each of which was
comprised of a subset of the workshop attendees and interested observers. The
first two panels, which identified the Priority Research Directions, were
differentiated by choice of materials set. The first, LED Science, focused on
inorganic light-emitting materials such as the Group III nitrides, oxides, and
novel oxychalcogenides. The second, OLED Science, considered organic materials
that are carbon-based molecular, polymeric, or dendrimeric compounds. The third
panel, which identified the Cross-Cutting Research Directions, explored
cross¬cutting and novel materials science and optical physics themes such as
light extraction from solids, hybrid organic-inorganic and unconventional
materials, and light-matter interactions.
LED Science. Single-color, inorganic, light-emitting diodes (LEDs)
are already widely used and are bright, robust, and long-lived. The challenge is
to achieve white-light emission with high-efficiency and high-color rendering
quality at acceptable cost while maintaining these advantages. The bulk of
current research focuses on the Group III-nitride materials. Our understanding
of how these materials behave and can be controlled has advanced significantly
in the past decade, but significant scientific mysteries remain. These include
(1) determining whether there are as-yet undiscovered or undeveloped materials
that may offer significant advantages over current materials; (2) understanding
and optimizing ways of generating white light from other wavelengths; (3)
determining the role of piezoelectric and polar effects throughout the device
but particularly at interfaces; and (4) understanding the basis for some of the
peculiarities of the nitrides, the dominant inorganic SSL materials today, such
as their apparent tolerance of high defect densities, and the difficulty of
realizing efficient light emission at all visible wavelengths.
OLED Science. Organic light emitting devices (OLEDs) based on
polymeric or molecular thin films have been under development for about two
decades, mostly for applications in flat-panel displays, which are just
beginning to achieve commercial success. They have a number of attractive
properties for SSL, including ease (and potential affordability) of processing
and the ability to tune device properties via chemical modification of the
molecular structure of the thin film components. This potential is coupled with
challenges that have so far prevented the simultaneous achievement of high
brightness at high efficiency and long device lifetime. Organic thin films are
often structurally complex, and thin films that were long considered “amorphous”
can exhibit order on the molecular (nano) scale. Research areas of particularly
high priority include (1) quantifying local order and understanding its role in
the charge transport and light-emitting properties of organic thin films, (2)
developing the knowledge and expertise to synthesize and characterize organic
compounds at a level of purity approaching that of inorganic semiconductors, and
understanding the role of various low-level impurities on device properties in
order to control materials degradation under SSL-relevant conditions, and (3)
understanding the complex interplay of effects among the many individual
materials and layers in an OLED to enable an integrated approach to OLED design.
Cross-Cutting and Novel Materials Science and Optical Physics.
Some areas of scientific research are relevant to all materials systems. While
research on inorganic and organic materials has thus far proceeded
independently, the optimal material system and device architecture for SSL may
be as yet undiscovered and, furthermore, may require the integration of both
classes of materials in a single system. Research directions that could enable
new materials and architectures include (1) the design, synthesis, and
integration of novel, nanoscale, heterogeneous building blocks, such as
functionalized carbon nanotubes or quantum dots, with properties optimized for
SSL, (2) the development of innovative architectures to control the flow of
energy in a light emitting material to maximize the efficiency of light
extraction, (3) the exploitation of strong coupling between light and matter to
increase the quality and efficiency of emitted light, (4) the development of
multiscale modeling techniques extending from the atomic or molecular scale to
the device and system scale, and (5) the development and use of new
experimental, theoretical, and computational tools to probe and understand the
fundamental properties of SSL materials at the smallest scales of length and
time.
SUMMARY
The workshop participants enthusiastically concluded that the time is ripe for
new fundamental science to beget a revolution in lighting technology. SSL
sources based on organic and inorganic materials have reached a level of
efficiency where it is possible to envision their use for general illumination.
The research areas articulated in this report are targeted to enable disruptive
advances in SSL performance and realization of this dream. Broad penetration of
SSL technology into the mass lighting market, accompanied by vast savings in
energy usage, requires nothing less. These new “good ideas” will be represented
not by light bulbs, but by an entirely new lighting technology for the 21st
century and a bright, energy-efficient future indeed.
(List of recent BES workshop reports)
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Basic Research Needs for Superconductivity
This report is based on a BES Workshop on Superconductivity, May 8–10, 2006, to examine
the prospects for superconducting grid technology and its potential for
significantly increasing grid capacity, reliability, and efficiency to meet the
growing demand for electricity over the next century.
As an energy carrier,
electricity has no rival with regard to its environmental cleanliness,
flexibility in interfacing with multiple production sources and end uses, and
efficiency of delivery. In fact, the electric power grid was named “the greatest
engineering achievement of the 20th century” by the National Academy of
Engineering. This grid, a technological marvel ingeniously knitted together from
local networks growing out from cities and rural centers, may be the biggest and
most complex artificial system ever built. However, the growing demand for
electricity will soon challenge the grid beyond its capability, compromising its
reliability through voltage fluctuations that crash digital electronics,
brownouts that disable industrial processes and harm electrical equipment, and
power failures like the North American blackout in 2003 and subsequent blackouts
in London, Scandinavia, and Italy in the same year. The North American blackout
affected 50 million people and caused approximately $6 billion in economic
damage over the four days of its duration.
Superconductivity offers powerful new opportunities for
restoring the reliability of the power grid and
increasing its capacity and efficiency. Superconductors are capable of
carrying current without loss, making the parts of the grid they replace
dramatically more efficient. Superconducting wires carry up to five times the
current carried by copper wires that have the same cross section, thereby
providing ample capacity for future expansion while requiring no increase in the
number of overhead access lines or underground conduits. Their use is especially
attractive in urban areas, where replacing copper with superconductors in
power-saturated underground conduits avoids expensive new underground
construction. Superconducting transformers cut the volume, weight, and losses of
conventional transformers by a factor of two and do not require the
contaminating and flammable transformer oils that violate urban safety codes.
Unlike traditional grid technology, superconducting fault current limiters are
smart. They increase their resistance abruptly in response to overcurrents from
faults in the system, thus limiting the overcurrents and protecting the grid
from damage. They react fast in both triggering and automatically resetting
after the overload is cleared, providing a new, self-healing feature that
enhances grid reliability. Superconducting reactive power regulators further
enhance reliability by instantaneously adjusting reactive power for maximum
efficiency and stability in a compact and economic package that is easily sited
in urban grids. Not only do superconducting motors and generators cut losses,
weight, and volume by a factor of two, but they are also much more tolerant of
voltage sag, frequency instabilities, and reactive power fluctuations than their
conventional counterparts.
The
challenge facing the electricity grid to provide abundant, reliable power will
soon grow to crisis proportions. Continuing urbanization remains the dominant
historic demographic trend in the United States and in the world. By 2030,
nearly 90% of the U.S. population will reside in cities and suburbs, where
increasingly strict permitting requirements preclude bringing in additional
overhead access lines, underground cables are saturated, and growth in power
demand is highest. The power grid has never faced a challenge so great or so
critical to our future productivity, economic growth, and quality of life.
Incremental advances in existing grid technology are not capable of solving the
urban power bottleneck. Revolutionary new solutions are needed — the kind that
come only from superconductivity.
The Basic Energy Sciences
Workshop on Superconductivity
The
Basic Energy Sciences (BES) Workshop on Superconductivity brought together more
than 100 leading scientists from universities, industry, and national
laboratories in the United States, Europe, and Asia. Basic and applied
scientists were generously represented, creating a valuable and rare opportunity
for mutual creative stimulation. Advance planning for the workshop involved two
U.S. Department of Energy offices: the Office of Electricity Delivery and Energy
Reliability, which manages research and development for superconducting
technology, and the Office of Basic Energy Sciences, which manages basic
research on superconductivity.
Performance of
superconductors
The
workshop participants found that superconducting technology for wires, power
control, and power conversion had already passed the design and demonstration
stages. The discovery of copper oxide superconductors in 1986 was a landmark
event, bringing forth a new generation of superconducting materials with
transition temperatures of 90 K or above, which allow cooling with inexpensive
liquid nitrogen or mechanical cryocoolers. Cables, transformers, and rotating
machines using first-generation (1G) wires based on Bi2Sr2Ca2Cu3Ox
allowed new design principles and performance standards to be established that
enabled superconducting grid technology to compete favorably with traditional
copper devices. The early 2000s saw a paradigm shift to second-generation (2G)
wires based on YBa2Cu3O7 that use a very
different materials architecture; these have the potential for better
performance over a larger operating range with respect to temperature and
magnetic field. 2G wires have advanced rapidly; their current-carrying ability
has increased by a factor of 10, and their usable length has increased to 300
meters, compared with only a few centimeters five years ago.
While
2G superconducting wires now considerably outperform copper wires in their
capacity for and efficiency in transporting current, significant gaps in their
performance improvements remain. The alternating-current (ac) losses in
superconductors are a major source of heat generation and refrigeration costs;
these costs decline significantly as the maximum lossless current-carrying
capability increases. For the same operating current, a tenfold increase in the
maximum current-carrying capability of the wire cuts the heat generated as a
result of ac losses by the same factor of 10. For transporting current on the
grid, an order-of-magnitude increase in current-carrying capability is needed to
reduce the operational cost of superconducting lines and cables to competitive
levels. Transformers, fault current limiters, and rotating machinery all contain
coils of superconducting wire that create magnetic fields essential to their
operation. 2G wires carry significantly less current in magnetic fields as small
as 0.1 to 0.5 T, which are found in transformers and fault current limiters, and
in fields of 3 to 5 T, which are needed for motors and generators. The
fundamental factors that limit the current-carrying performance of 2G wires in
magnetic fields must be understood and overcome to produce a five- to tenfold
increase in their performance rating.
Increasing the current-carrying capability of superconductors requires blocking
the motion of “Abrikosov vortices” — nanoscale tubes of magnetic flux that form
spontaneously inside superconductors upon exposure to magnetic fields. Vortices
are immobilized by artificial defects in the superconducting material that
attract the vortices and pin them in place. To pin vortices effectively, an
understanding not only of the pinning strength of
individual defects for individual vortices but also of the collective
effects of many defects interacting with many vortices is needed. The
similarities of vortex pinning and flow to glacier flow around rock obstacles,
avalanche flow in landslides, and earthquake motion at fault lines are reflected
in the colloquial name “vortex matter.” To achieve a five- to tenfold increase
in vortex pinning and current-carrying ability in superconductors, we must learn
how to bridge the scientific gap separating the microscopic behavior of
individual vortices and pinning sites in a superconductor from its macroscopic
current-carrying ability.
Cost of superconductors
Although superconducting wires perform significantly better than copper wires in
transmitting electricity, their cost is still too high. The cost of manufactured
superconducting wires must be reduced by a factor of 10 to 100 to make them
competitive with copper. Much of the manufacturing cost arises from the complex
architecture of 2G wires, which are made up of a flexible metallic substrate
(often of a magnetic material) on which up to seven additional layers must be
sequentially deposited while a specific crystalline orientation is maintained
from layer to layer. Significant advances in materials science are needed to
simplify the architecture and the manufacturing process while maintaining
crystalline orientation, flexibility, superconductor composition, and protection
from excessive heat if there is an accidental loss of superconductivity.
Beyond
their manufacturing cost, the operating cost of superconductors must be reduced.
Copper wires require no active cooling to operate, while superconductors must be
cooled to temperatures of between 50 and 77 K for most applications. The added
cost of refrigeration is a significant factor in superconductor operating cost.
Reducing refrigeration costs for future generations of
superconducting applications is a major technology driver for the discovery or
design of new superconducting materials with higher transition temperatures.
Phenomena of
superconductivity
These
achievements and challenges in superconducting technology are matched by equally
promising achievements and challenges in the fundamental science of
superconductivity. Since 1986, new materials discoveries have pushed the
superconducting transition temperature in elements from 12 to 20 K (for Li under
pressure), in heavy fermion compounds from 1.5 to 18.5 K (for PuCoGa5),
in noncuprate oxides from 13 to 30 K (for Ba1-xKxBiO3),
in binary borides from 6 to 40 K (for MgB2), and in graphite
intercalation compounds from 4.05 to 11.5 K (for CaC6). In addition,
superconductivity has been discovered for the first time in carbon compounds
like boron-doped diamond (11 K) and fullerides (up to 40 K for Cs3C60
under pressure), as well as in borocarbides (up to 16.5 K with metastable phases
up to 23 K). We are finding that superconductivity, formerly thought to be a
rare occurrence in special compounds, is a common behavior of correlated
electrons or “electron matter” in materials. As of this writing, fully
55 elements display superconductivity at some combination of temperature and
pressure; this number is up from 43 in 1986, an increase of 28%.
As the
number and classes of materials displaying superconductivity have mushroomed, so
also has the variety of pairing mechanisms and symmetries of superconductivity.
The superconducting state is built of “Cooper pairs” — composite objects
composed of two electrons bound by a pairing mechanism. The spatial relation of
the charges in a pair is described by its pairing symmetry. Copper oxides are
known to have d-wave pairing symmetry, in contrast to the s-wave pairing of
conventional superconductors; Sr2RuO4 and certain organic
superconductors appear to be p-wave. Superconductivity has been found close to
magnetic order and can either compete against it or coexist with it, suggesting
that spin plays a role in the pairing mechanism. Tantalizing glimpses of
superconducting-like states at very high temperatures have been seen in the
underdoped phase of yttrium barium copper oxide (YBCO), in the form of
pseudogaps and of strong transverse electric fields induced by temperature
gradients (the “vortex Nernst effect”) that typically imply vortex motion. The
proliferation of new classes of superconducting materials; of record-breaking
transition temperatures in the known classes of superconductors; of
unconventional pairing mechanisms and symmetries of superconductivity; and of
exotic, superconducting-like features well above the superconducting transition
temperature all imply that superconducting electron matter is a far richer field
than we suspected even 10 years ago.
While
there are many fundamental puzzles in this profusion of intriguing effects, the
central challenge with the biggest impact is to understand the mechanisms of
high-temperature superconductivity. This is difficult precisely because the
mechanisms are entangled with these anomalous normal state effects. Such effects
are noticeably absent in the normal states of conventional superconductors. In
the underdoped copper oxides (as in other complex oxides), there are many signs
of highly correlated normal states, like the spontaneous formation of stripes
and pseudogaps that exist above the superconducting transition temperature. They
may be necessary precursors to the high-temperature superconducting state, or
perhaps competitors, and it seems clear that an explanation of superconductivity
will include these correlated normal states in the same framework. For two
decades, theorists have struggled and failed to find a solution, even as
experimentalists tantalize them with ever more fascinating anomalous features.
The more than 50 superconducting compounds in the copper oxide family
demonstrate that the mechanism of superconductivity is robust, and that it is
likely to apply widely in nature among other complex metals with highly
correlated normal states. Although finding the mechanism is frustratingly
difficult, its value, once found, makes the struggle compelling.
Research directions
The BES
Workshop on Superconductivity identified seven “priority research directions”
and two “cross-cutting research directions” that capture the promise of
revolutionary advances in superconductivity science and technology. The first
seven directions set a course for research in superconductivity that will
exploit the opportunities uncovered by the workshop panels in materials,
phenomena, theory, and applications. These research directions extend the reach
of superconductivity to higher transition temperatures and higher
current-carrying capabilities, create new families of superconducting materials
with novel nanoscale structures, establish fundamental principles for
understanding the rich variety of superconducting behavior within a single
framework, and develop tools and materials that enable new superconducting
technology for the electric power grid that will dramatically improve its
capacity, reliability, and efficiency for the coming century.
The
seven priority research directions identified by the workshop take full
advantage of the rapid advances in nanoscale science and technology of the last
five years. Superconductivity is ultimately a nanoscale phenomenon. Its two
composite building blocks — Cooper pairs mediating the superconducting state and
Abrikosov vortices mediating its current-carrying ability — have dimensions
ranging from a tenth of a nanometer to a hundred nanometers. Their nanoscale
interactions among themselves and with structures of comparable size determine
all of their superconducting properties. The continuing development of powerful
nanofabrication techniques, by top-down lithography and bottom-up self-assembly,
creates promising new horizons for designer superconducting materials with
higher transition temperatures and current-carrying ability. Nanoscale
characterization techniques with ever smaller spatial and temporal resolution —
including aberration-corrected electron microscopy, nanofocused x-ray beams from
high-intensity synchrotrons, scanning probe microscopy, and ultrafast x‑ray
laser spectroscopy — allow us to track the motion of a single vortex interacting
with a single pinning defect or to observe Cooper pair making and pair breaking
near a magnetic impurity atom. The numerical simulation of superconducting
phenomena in confined geometries using computer clusters of a hundred or more
nodes allows the interaction of Cooper pairs and Abrikosov vortices with
nanoscale boundaries and architectures to be isolated. Understanding these
nanoscale interactions with artificial boundaries enables the numerical design
of functional superconductors. The promise of nanoscale fabrication,
characterization, and simulation for advancing the fundamental science of
superconductivity and rational design of functional superconducting materials
for next-generation grid technology has never been higher.
A key
outcome of the BES Workshop on Superconductivity has been a strong sense of
optimism and awareness of the opportunity that spans the community of
participants in the basic and applied sciences. In the last decade, enormous
strides have been made in understanding the science of high-temperature
superconductivity and exploiting it for electricity production, distribution,
and use. The promise of developing a smart, self-healing grid based on
superconductors that require no cooling is an inspiring “grand energy challenge”
that drives the frontiers of basic science and applied technology. Meeting this
21st century challenge would rival the 20th century achievement of providing
electricity for everyone at the flick of a switch. The seven priority and two
cross-cutting research directions identified by the workshop participants offer
the potential for achieving this challenge and creating a transformational
impact on our electric power infrastructure.
(List of recent BES workshop reports)
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The Path to Sustainable Nuclear Energy
Basic and Applied Research Opportunities for Advanced Fuel Cycles
This report is based on a small DOE-sponsored
workshop held in September 2005 to identify new basic science that will be the foundation for advances in nuclear fuel-cycle technology in the near term, and for changing the nature of fuel cycles and of the nuclear energy industry in the long
term. The goals are to enhance the development of nuclear energy, to maximize energy production in nuclear reactor parks, and to minimize radioactive wastes, other environmental impacts, and proliferation risks.
The limitations of the once-through fuel cycle can be overcome by adopting a closed fuel cycle, in which the irradiated fuel is reprocessed and its components are separated into streams that are recycled into a reactor or disposed of in appropriate waste forms. The recycled fuel is irradiated in a reactor, where certain constituents are partially transmuted into heavier isotopes via neutron capture or into lighter isotopes via fission. Fast reactors are required to complete the transmutation of long-lived isotopes. Closed fuel cycles are encompassed by the Department of Energy’s Advanced Fuel Cycle Initiative (AFCI), to which basic scientific research can contribute.
Two nuclear reactor system architectures can meet the AFCI objectives: a “single-tier” system or a “dual-tier” system. Both begin with light water reactors and incorporate fast reactors. The “dual-tier” systems transmute some plutonium and neptunium in light water reactors and all remaining transuranic elements (TRUs) in a closed-cycle fast reactor.
Basic science initiatives are needed in two broad areas:
• Near-term impacts that can enhance the development of either “single-tier” or “dual-tier” AFCI systems, primarily within the next 20 years, through basic research. Examples:
• Dissolution of spent fuel, separations of elements for TRU recycling and transmutation |
• Design, synthesis, and testing of inert matrix nuclear fuels and non-oxide fuels |
• Invention and development of accurate on-line monitoring systems for chemical and nuclear species in the nuclear fuel cycle |
• Development of advanced tools for designing reactors with reduced margins and lower costs |
• Long-term nuclear reactor development requires basic science breakthroughs:
• Understanding of materials behavior under extreme environmental conditions |
• Creation of new, efficient, environmentally benign chemical separations methods |
• Modeling and simulation to improve nuclear reaction cross-section data, design new materials and separation system, and propagate uncertainties within the fuel cycle |
• Improvement of proliferation resistance by strengthening safeguards technologies and decreasing the attractiveness of nuclear materials |
A series of translational tools is proposed to advance the AFCI objectives and to bring the basic science concepts and processes promptly into the technological sphere. These tools have the potential to revolutionize the approach to nuclear engineering R&D by replacing lengthy experimental campaigns with a rigorous approach based on modeling, key fundamental experiments, and advanced simulations.
(List of recent BES workshop reports)
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Basic Research Needs for Solar Energy Utilization
This report is based on a BES Workshop on Solar
Energy Utilization, April 18–21, 2005, to examine the challenges and opportunities for the development of solar energy as a competitive energy source and to identify the technical barriers to large-scale implementation of solar energy and the basic research directions showing promise to overcome
them.
World demand for energy is projected to more than double by 2050 and to more than triple by the end of the century.
Incremental improvements in existing energy networks will not be adequate to supply this demand sustainably.
Finding sufficient supplies of clean energy for the future is one of society’s most daunting challenges.
Sunlight provides by far the largest of all carbon-neutral energy sources.
More energy from sunlight strikes the Earth in one hour (4.3 × 1020 J) than all the energy consumed on the planet in a year (4.1 ×
1020 J). We currently exploit this solar resource through solar electricity — a $7.5 billion industry growing at a rate of 35–40% per annum — and solar-derived fuel from biomass, which provides the primary energy source for over a billion people.
Yet, in 2001, solar electricity provided less than 0.1% of the world's electricity, and solar fuel from modern (sustainable) biomass provided less than 1.5% of the world's energy.
The huge gap between our present use of solar energy and its enormous undeveloped potential defines a grand challenge in energy research.
Sunlight is a compelling solution to our need for clean, abundant sources of energy in the future.
It is readily available, secure from geopolitical tension, and poses no threat to our environment through pollution or to our climate through greenhouse gases.
This report of the Basic Energy Sciences Workshop on Solar Energy Utilization identifies the key scientific challenges and research directions that will enable efficient and economic use of the solar resource to provide a significant fraction of global primary energy by the mid
21st century. The report reflects the collective output of the workshop attendees, which included 200 scientists representing academia, national laboratories, and industry in the United States and abroad, and the U.S. Department of Energy’s Office of Basic Energy Sciences and Office of Energy Efficiency and Renewable Energy.
Solar energy conversion systems fall into three categories according to their primary energy product: solar electricity, solar fuels, and solar thermal systems. Each of the three generic approaches to exploiting the solar resource has untapped capability well beyond its present usage. Workshop participants considered the potential of all three approaches, as well as the potential of hybrid systems that integrate key components of individual technologies into novel cross-disciplinary paradigms.
SOLAR ELECTRICITY
The challenge in converting sunlight to electricity via photovoltaic solar cells is dramatically reducing the cost/watt of delivered solar electricity — by approximately a factor of 5–10 to compete with fossil and nuclear electricity and by a factor of 25–50 to compete with primary fossil energy.
New materials to efficiently absorb sunlight, new techniques to harness the full spectrum of wavelengths in solar radiation, and new approaches based on nanostructured architectures can revolutionize the technology used to produce solar electricity.
The technological development and successful commercialization of single-crystal solar cells demonstrates the promise and practicality of photovoltaics, while novel approaches exploiting thin films, organic semiconductors, dye sensitization, and quantum dots offer fascinating new opportunities for cheaper, more efficient, longer-lasting systems.
Many of the new approaches outlined by the workshop participants are enabled by (1) remarkable recent advances in the fabrication of nanoscale architectures by novel top-down and bottom-up techniques; (2) advances in nanoscale characterization using electron, neutron, and x-ray scattering and spectroscopy; and (3) sophisticated computer simulations of electronic and molecular behavior in nanoscale semiconductor assemblies using density functional theory.
Such advances in the basic science of solar electric conversion, coupled to the new semiconductor materials now available, could drive a revolution in the way that solar cells are conceived, designed, implemented, and manufactured.
SOLAR FUELS
The inherent day-night and sunny-cloudy cycles of solar radiation necessitate an effective method to store the converted solar energy for later dispatch and distribution.
The most attractive and economical method of storage is conversion to chemical fuels.
The challenge in solar fuel technology is to produce chemical fuels directly from sunlight in a robust, cost-efficient fashion.
For millennia, cheap solar fuel production from biomass has been the primary energy source on the planet.
For the last two centuries, however, energy demand has outpaced biomass supply.
The use of existing types of plants requires large land areas to meet a significant portion of primary energy demand. Almost all of the arable land on Earth would need to be covered with the fastest-growing known energy crops, such as switchgrass, to produce the amount of energy currently consumed from fossil fuels annually.
Hence, the key research goals are (1) application of the revolutionary advances in biology and biotechnology to the design of plants and organisms that are more efficient energy conversion “machines,” and (2) design of highly efficient, all-artificial, molecular-level energy conversion machines exploiting the principles of natural photosynthesis.
A key element in both approaches is the continued elucidation — by means of structural biology, genome sequencing, and proteomics — of the structure and dynamics involved in the biological conversion of solar radiation to sugars and carbohydrates.
The revelation of these long-held secrets of natural solar conversion by means of cutting-edge experiment and theory will enable a host of exciting new approaches to direct solar fuel production.
Artificial nanoscale assemblies of new organic and inorganic materials and morphologies, replacing natural plants or algae, can now use sunlight to directly produce
H2 by splitting water and hydrocarbons via reduction of atmospheric
CO2. While these laboratory successes demonstrate the appealing promise of direct solar fuel production by artificial molecular machines, there is an enormous gap between the present state of the art and a deployable technology.
The current laboratory systems are unstable over long time periods, too expensive, and too inefficient for practical implementation.
Basic research is needed to develop approaches and systems to bridge the gap between the scientific frontier and practical technology.
SOLAR THERMAL SYSTEMS
The key challenge in solar thermal technology is to identify cost-effective methods to convert sunlight into storable, dispatchable thermal energy.
Reactors heated by focused, concentrated sunlight in thermal towers reach temperatures exceeding 3,000°C, enabling the efficient chemical production of fuels from raw materials without expensive catalysts.
New materials that withstand the high temperatures of solar thermal reactors are needed to drive applications of this technology.
New chemical conversion sequences, like those that split water to produce H2 using the heat from nuclear fission reactors, could be used to convert focused solar thermal energy into chemical fuel with unprecedented efficiency and cost effectiveness.
At lower solar concentration temperatures, solar heat can be used to drive turbines that produce electricity mechanically with greater efficiency than the current generation of solar photovoltaics.
When combined with solar-driven chemical storage/release cycles, such as those based on the dissociation and synthesis of ammonia, solar engines can produce electricity continuously 24 h/day.
Novel thermal storage materials with an embedded phase transition offer the potential of high thermal storage capacity and long release times, bridging the diurnal cycle.
Nanostructured thermoelectric materials, in the form of nanowires or quantum dot arrays, offer a promise of direct electricity production from temperature differentials with efficiencies of 20–30% over a temperature differential of a few hundred degrees Celsius.
The much larger differentials in solar thermal reactors make even higher efficiencies possible.
New low-cost, high-performance reflective materials for the focusing systems are needed to optimize the cost effectiveness of all concentrated solar thermal technologies.
PRIORITY RESEARCH DIRECTIONS
Workshop attendees identified thirteen priority research directions (PRDs) with high potential for producing scientific breakthroughs that could dramatically advance solar energy conversion to electricity, fuels, and thermal end uses.
Many of these PRDs address issues of concern to more than one approach or technology.
These cross-cutting issues include (1) coaxing cheap materials to perform as well as expensive materials in terms of their electrical, optical, chemical, and physical properties; (2) developing new paradigms for solar cell design that surpass traditional efficiency limits; (3) finding catalysts that enable inexpensive, efficient conversion of solar energy into chemical fuels; (4) identifying novel methods for self-assembly of molecular components into functionally integrated systems; and (5) developing materials for solar energy conversion infrastructure, such as transparent conductors and robust, inexpensive thermal management materials.
A key outcome of the workshop is the sense of optimism in the cross-disciplinary community of solar energy scientists spanning academia, government, and industry. Although large barriers prevent present technology from producing a significant fraction of our primary energy from sunlight by the
mid-21st century, workshop participants identified promising routes for basic research that can bring this goal within reach.
Much of this optimism is based on the continuing, rapid worldwide progress in nanoscience.
Powerful new methods of nanoscale fabrication, characterization, and simulation — using tools that were not available as little as five years ago — create new opportunities for understanding and manipulating the molecular and electronic pathways of solar energy conversion.
Additional optimism arises from impressive strides in genetic sequencing, protein production, and structural biology that will soon bring the secrets of photosynthesis and natural bio-catalysis into sharp focus.
Understanding these highly effective natural processes in detail will allow us to modify and extend them to molecular reactions that directly produce sunlight-derived fuels that fit seamlessly into our existing energy networks.
The rapid advances on the scientific frontiers of nanoscience and molecular biology provide a strong foundation for future breakthroughs in solar energy
conversion.
(List of recent BES workshop reports)
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Advanced Computational Materials Science:
Application to Fusion and Generation IV Fission Reactors
This report is based on a workshop held
March
31–April 2, 2004, to determine the degree to which an increased effort in modeling and simulation could help bridge the gap between the data that is needed to support the implementation of advanced nuclear
technologies and the data that can be obtained in available experimental
facilities.
The need to develop materials capable of performing in the severe operating environments expected in fusion and fission (Generation IV) reactors represents a significant challenge in materials science. There is a range of potential Gen-IV fission reactor design concepts and each concept has its own unique demands. Improved economic performance is a major goal of the Gen-IV designs. As a result, most designs call for significantly higher operating temperatures than the current generation of LWRs to obtain higher thermal efficiency. In many cases, the desired operating temperatures rule out the use of the structural alloys employed today. The very high operating temperature (up to 1000°C) associated with the NGNP is a prime example of an attractive new system that will require the development of new structural materials. Fusion power plants represent an even greater challenge to structural materials development and application. The operating temperatures, neutron exposure levels and thermo-mechanical stresses are comparable to or greater than those for proposed Gen-IV fission reactors. In addition, the transmutation products created in the structural materials by the high energy neutrons produced in the DT plasma can profoundly influence the microstructural evolution and mechanical behavior of these materials.
Although the workshop addressed issues relevant to both Gen-IV and fusion reactor materials, much of the discussion focused on fusion; the same focus is reflected in this report. Most of the physical models and computational methods presented during the workshop apply equally to both types of nuclear energy systems. The primary factor that differentiates the materials development path for the two systems is that nearly prototypical irradiation environments for Gen-IV materials can be found or built in existing fission reactors. This is not the case for fusion. The only fusion-relevant, 14 MeV neutron sources ever built (such as the rotating target neutron sources, RTNS-I and -II at LLNL) were relatively low-power accelerator based systems. The RTNS-II “high” flux irradiation volume was quite small, less than 1
cm3, and only low doses could be achieved. The maximum dose data obtained was much less than 0.1 dpa. Thus, RTNS-II, which last operated in 1986, provided only a limited opportunity for fundamental investigations of the effects of 14 MeV neutrons characteristic of DT fusion.
Historically, both the fusion and fission reactor programs have taken advantage of and built on research carried out by the other program. This leveraging can be expected to continue over the next ten years as both experimental and modeling activities in support of the Gen-IV program grow substantially. The Gen-IV research will augment the fusion studies (and vice versa) in areas where similar materials and exposure conditions are of interest. However, in addition to the concerns that are common to both fusion and advanced fission reactor programs, designers of a future DT fusion reactor have the unique problem of anticipating the effects of the 14 MeV neutron source term. In particular, the question arises whether irradiation data obtained in a near-prototypic irradiation environment such as the IFMIF are needed to verify results obtained from computational materials research. The need for a theory and modeling effort to work hand-in-hand with a complementary experimental program for the purpose of model development and verification, and for validation of model predictions was extensively discussed at the workshop. There was a clear consensus that an IFMIF-like irradiation facility is likely to be required to contribute to this research. However, the question of whether IFMIF itself is needed was explored from two different points of view at the workshop. These complementary (and in some cases opposing) points of view can be coarsely characterized as “scientific” and “engineering.”
The recent and anticipated progress in computational materials science presented at the workshop provides some confidence that many of the scientific questions whose answers will underpin the successful use of structural materials in a DT fusion reactor can be addressed in a reasonable time frame if sufficient resources are devoted to this effort. For example, advances in computing hardware and software should permit improved (and in some cases the first) descriptions of relevant properties in alloys based on
ab initio calculations. Such calculations could provide the basis for realistic interatomic potentials for alloys, including alloy-He potentials, that can be applied in classical molecular dynamics simulations. These potentials must have a more detailed description of many-body interactions than accounted for in the current generation which are generally based on a simple embedding function. In addition, the potentials used under fusion reactor conditions (very high PKA energies) should account for the effects of local electronic excitation and electronic energy loss. The computational cost of using more complex potentials also requires the next generation of massively parallel computers. New results of
ab initio and atomistic calculations can be coupled with ongoing advances in kinetic and phase field models to dramatically improve predictions of the non-equilibrium, radiation-induced evolution in alloys with unstable microstructures. This includes phase stability and the effects of helium on each microstructural component.
However, for all its promise, computational materials science is still a house under construction. As such, the current reach of the science is limited. Theory and modeling can be used to develop understanding of known critical physical phenomena, and computer experiments can, and have been used to, identify new phenomena and mechanisms, and to aid in alloy design. However, it is questionable whether the science will be sufficiently mature in the foreseeable future to provide a rigorous scientific basis for predicting critical materials’ properties, or for extrapolating well beyond the available validation database.
Two other issues remain even if the scientific questions appear to have been adequately answered. These are licensing and capital investment. Even a high degree of scientific confidence that a given alloy will perform as needed in a particular Gen-IV or fusion environment is not necessarily transferable to the reactor licensing or capital market regimes. The philosophy, codes, and standards employed for reactor licensing are properly conservative with respect to design data requirements. Experience with the U.S. Nuclear Regulatory Commission suggests that only modeling results that are strongly supported by relevant, prototypical data will have an impact on the licensing process. In a similar way, it is expected that investment on the scale required to build a fusion power plant (several billion dollars) could only be obtained if a very high level of confidence existed that the plant would operate long and safely enough to return the investment.
These latter two concerns appear to dictate that an experimental facility capable of generating a sufficient, if limited, body of design data under essentially prototypic conditions (i.e. with ~14 MeV neutrons) will ultimately be required for the commercialization of fusion power. An aggressive theory and modeling effort will reduce the time and experimental investment required to develop the advanced materials that can perform in a DT fusion reactor environment. For example, the quantity of design data may be reduced to that required to confirm model predictions for key materials at critical exposure conditions. This will include some data at a substantial fraction of the anticipated end-of-life dose, which raises the issue of when such an experimental facility is required. Long lead times for construction of complex facilities, coupled with several years irradiation to reach the highest doses, imply that the decision to build any fusion-relevant irradiation facility must be made on the order of 10 years before the design data is needed.
Two related areas of research can be used as reference points for the expressed need to obtain experimental validation of model predictions. Among the lessons learned from ASCI, the importance of code validation and verification was emphasized at the workshop. Despite an extensive investment in theory and modeling of the relevant physics, the NIF is being built at LLNL to verify the performance of the physics codes. Similarly, while the U.S. and international fusion community has invested considerable resources in simulating the behavior of magnetically-confined plasmas, a series of experimental devices (e.g. DIII-D, TFTR, JET, NSTX, and NCSX) have been, or will be, built and numerous experiments carried out to validate the predicted plasma performance on the route to ITER and a demonstration fusion power
reactor.
(List of recent BES workshop reports)
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Opportunities for Discovery:
Theory and Computation in Basic Energy Sciences
This report is based on the deliberations of the
BESAC Subcommittee on Theory and Computation following meetings on February 22
and April 17–16, 2004, to obtain testimony and discuss input from the
scientific community on research directions for theory and computation to
advance the scientific mission of the Office of Basic Energy Sciences
(BES). New scientific frontiers, recent advances in
theory, and rapid increases in computational capabilities have created
compelling opportunities for theory and computation to advance the science.
The prospects for success in the experimental programs of BES will be enhanced
by pursuing these opportunities. This report makes the case for an
expanded research program in theory and computation in BES.
The Subcommittee on Theory and Computation of the Basic Energy Sciences
Advisory Committee was charged on October 17, 2003, by the Director, Office of
Science, with identifying current and emerging challenges and opportunities
for theoretical research within the scientific mission of BES, paying
particular attention to how computing will be employed to enable that
research. A primary purpose of the Subcommittee was to identify those
investments that are necessary to ensure that theoretical research will have
maximum impact in the areas of importance to BES, and to assure that BES
researchers will be able to exploit the entire spectrum of computational
tools, including leadership class computing facilities. The Subcommittee’s
Findings and Recommendations are presented in Section VII of the report.
A confluence of scientific events has enhanced the importance of theory and
computation in BES.
After considering both written and
verbal testimony from members of the scientific community, the Subcommittee
observed that a confluence of developments in scientific research over the
past fifteen years has quietly revolutionized both the present role and future
promise of theory and computation in the disciplines that comprise the Basic
Energy Sciences. Those developments fall into four broad categories:
1. |
a set of striking recent scientific successes that demonstrate the increased impact of theory and computation; |
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the appearance of new scientific frontiers in which innovative theory is required to lead inquiry and unravel the mysteries posed by new observations; |
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the development of new experimental capabilities, including large-scale facilities, that provide challenging new data and demand both fundamental and computationally intensive theory to realize their promise; |
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the ongoing increase of computational capability provided by continued improvements in computers and algorithms, which has dramatically amplified the power and applicability of theoretical research. |
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The sum of these events argues powerfully that now is the time for an increase
in the investment by BES in theory and computation, including modeling and
simulation. |
Emerging themes in the Basic Energy Sciences and nine specific areas of
opportunity for scientific discovery.
The report
identifies nine specific areas of opportunity in which expanded investment in
theory and computation holds great promise to enhance discovery in the
scientific mission of BES. While this list is not exhaustive, it
represents a range of persuasive prospects broadly characterized by the themes
of “Complexity” and “Control” that describe much of the BES
portfolio. The challenges and promise of theory in each of these nine
areas are described in detail.
Connecting theory with experiment.
Connecting the BES
theory and computation programs with experimental research taking place at
existing or planned BES facilities deserves a high priority. BES should
undertake a major new thrust to significantly augment its theoretical and
computational programs coupled to experimental research at its major
facilities. We also urge that such a new effort not be limited only to
research at the facilities but also address the coupling of theory and
computation with new capabilities involving “tabletop” experimental
science as well.
The unity of modern theory and computation.
For a number of
the research problems in BES, we are fortunate to know the equations that must
be solved. For this reason many BES disciplines are presently exploiting
high-end computation and are poised to use it at the leadership scale.
However, in many other areas of BES, we do not know all the equations, nor do
we have all the mathematical and physical insights we need, and therefore we
have not yet invented the required algorithms. In an expanded yet
balanced theory effort in BES, enhancements in computation must be accompanied
by enhancements in the rest of the theoretical endeavor. Conceptual
theory and computation are not separate enterprises.
Resources necessary for success in the BES theory enterprise.
A successful BES theory effort must provide the full spectrum of computational
resources, as well as support the development and maintenance of scientific
computer codes as shared scientific instruments. We find that BES is
ready for and requires access to leadership-scale computing to perform
calculations that cannot be done elsewhere, but also that a large amount of
essential BES computation falls between the leadership and the desktop
scales. Moreover, BES should provide support for the development and
maintenance of shared scientific software to enhance the scientific impact of
the BES-supported theory community and to remove a key obstacle to the
effective exploitation of high-end computing resources and facilities.
In summary, the Subcommittee finds that there is a compelling need for
BES to expand its programs to capture opportunities created by the combination
of new capabilities in theory and computation and the opening of new
experimental frontiers. Providing the right resources, supporting new
styles of theoretical inquiry, and building a properly balanced program are
all essential for the success of an expanded effort in theory and computation.
The experimental programs of BES will be enhanced by such an effort.
(List of recent BES workshop reports)
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Nanoscience Research
for Energy Needs
This report is based upon a BES-cosponsored
National Nanotechnology Initiative (NNI) Workshop held March 16–18, 2004, by
the Nanoscale Science, Engineering, and Technology (NSET)
Subcommittee of the National Science and Technology Council (NSTC) to address
the Grand Challenge in Energy Conversion and Storage set out in the NNI.
This report was originally released on June 24, 2004, during the Department of Energy NanoSummit.
The second edition that is provided here was issued in June 2005.
The world demand for energy is expected to
double to 28 terawatts by the year 2050. Compounding the challenge presented
by this projection is the growing need to protect our environment by
increasing energy efficiency and through the development of “clean”
energy sources. These are indeed global challenges, and their resolution
is vital to our energy security. Recent reports on Basic Research
Needs to Assure a Secure Energy Future (link) and Basic
Research Needs for the Hydrogen Economy (link)
have recognized that scientific breakthroughs and truly revolutionary
developments are demanded. Within this context, nanoscience and nanotechnology
present exciting and requisite approaches to addressing these challenges.
An interagency workshop to identify and articulate the relationship of
nanoscale science and technology to the nation's energy future was convened on
March 16-18, 2004 in Arlington, Virginia. The meeting was jointly
sponsored by the Department of Energy and, through the National Nanotechnology
Coordination Office, the other member agencies of the Nanoscale Science,
Engineering and Technology Subcommittee of the Committee on Technology,
National Science and Technology Council. This report is the outcome of
that workshop.
The workshop had 63 invited presenters with 32 from universities, 26 from
national laboratories and 5 from industry. This workshop is one in a
series intended to provide input from the research community on the next NNI
strategic plan, which the NSTC is required to deliver to Congress on the
first anniversary of the signing of the 21st Century Nanotechnology
R&D Act, Dec. 3, 2003.
At the root of the opportunities provided by nanoscience to impact our energy
security is the fact that all the elementary steps of energy conversion
(charge transfer, molecular rearrangement, chemical reactions, etc.) take
place on the nanoscale. Thus, the development of new nanoscale
materials, as well as the methods to characterize, manipulate, and assemble
them, creates an entirely new paradigm for developing new and revolutionary
energy technologies. The primary outcome of the workshop is the
identification of nine research targets in energy-related science and
technology in which nanoscience is expected to have the greatest impact:
• Scalable methods to split water
with sunlight for hydrogen production
• Highly selective
catalysts for clean and energy-efficient manufacturing
• Harvesting of solar
energy with 20 percent power efficiency and 100 times lower cost
• Solid-state
lighting at 50 percent of the present power consumption
• Super-strong,
light-weight materials to improve efficiency of cars, airplanes,
etc.
• Reversible hydrogen
storage materials operating at ambient temperatures
• Power transmission
lines capable of 1 gigawatt transmission
• Low-cost fuel
cells, batteries, thermoelectrics, and ultra-capacitors built from
nanostructured materials
• Materials synthesis
and energy harvesting based on the efficient and selective
mechanisms of biology
The report contains descriptions of many examples indicative of outcomes and
expected progress in each of these research targets. For successful
achievement of these research targets, participants recognized six
foundational and vital crosscutting nanoscience research themes:
• Catalysis by
nanoscale materials
• Using interfaces to
manipulate energy carriers
• Linking structure
and function at the nanoscale
• Assembly and
architecture of nanoscale structures
• Theory, modeling,
and simulation for energy nanoscience
• Scalable synthesis
methods
(List of recent BES workshop reports)
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DOE-NSF-NIH
Workshop on Opportunities in
THz Science
This report is based on a Workshop on
Opportunities in Terahetrz (THz) Science held February 12–14, 2004, to
discuss basic research problems that can be answered using THz radiation.
The
workshop did not focus on the wide range of potential applications of THz
radiation in engineering, defense and homeland security, or the commercial and
government sectors of the economy. The workshop was jointly sponsored by DOE,
NSF, and NIH.
The region of the electromagnetic
spectrum from 0.3 to 20 THz (10– 600 cm-1,
1 mm – 15 µm wavelength) is a frontier area for research in physics,
chemistry, biology, medicine, and materials sciences. Sources of high quality
radiation in this area have been scarce, but this gap has recently begun to be
filled by a wide range of new technologies. Terahertz radiation is now
available in both cw and pulsed form, down to single-cycles or less, with peak
powers up to 10 MW. New sources have led to new science in many areas, as
scientists begin to become aware of the opportunities for research progress in
their fields using THz radiation.
Science at a Time Scale Frontier: THz-frequency electromagnetic
radiation, with a fundamental period of around 1 ps, is uniquely suited to
study and control systems of central importance: electrons in highly-excited
atomic Rydberg states orbit at THz frequencies. Small molecules rotate at THz
frequencies. Collisions between gas phase molecules at room temperature last
about 1 ps. Biologically-important collective modes of proteins vibrate at THz
frequencies. Frustrated rotations and collective modes cause polar liquids
(such as water) to absorb at THz frequencies. Electrons in semiconductors and
their nanostructures resonate at THz frequencies. Superconducting energy gaps
are found at THz frequencies. An electron in Intel’s THz Transistor races
under the gate in ~1 ps. Gaseous and solid-state plasmas oscillate at THz
frequencies. Matter at temperatures above 10 K emits black-body radiation at
THz frequencies. This report also describes a tremendous array of other
studies that will become possible when access to THz sources and detectors is
widely available. The opportunities are limitless.
Electromagnetic Transition Region: THz radiation lies above the
frequency range of traditional electronics, but below the range of optical and
infrared generators. The fact that the THz frequency range lies in the
transition region between photonics and electronics has led to unprecedented
creativity in source development. Solid-state electronics, vacuum electronics,
microwave techniques, ultrafast visible and NIR lasers, single-mode
continuous-wave NIR lasers, electron accelerators ranging in size from a few
inches to a mile-long linear accelerator at SLAC, and novel materials have
been combined yield a large variety of sources with widely-varying output
characteristics. For the purposes of this report, sources are divided into 4
categories according to their (low, high) peak power and their (small, large)
instantaneous bandwidth.
THz experiments: Many classes of experiments can be performed
using THz electromagnetic radiation. Each of these will be enabled or
optimized by using a THz source with a particular set of specifications.
For
example, some experiments will be enabled by high average and peak power with
impulsive half-cycle excitation. Such radiation is available only from a new
class of sources based on sub-ps electron bunches produced in large
accelerators. Some high-resolution spectroscopy experiments will require cw
THz sources with kHz linewidths but only a few hundred microwatts of power.
Others will require powerful pulses with ≤1% bandwidth, available from
free-electron lasers and, very recently, regeneratively-amplified lasers and
nonlinear optical materials. Time-domain THz spectroscopy, with its time
coherence and extremely broad spectral bandwidth, will continue to expand its
reach and range of applications, from spectroscopy of superconductors to
sub-cutaneous imaging of skin cancer.
What is needed
The THz community needs a network: Sources of THz radiation are,
at this point, very rare in physics and materials science laboratories and
almost non-existent in chemistry, biology and medical laboratories. The
barriers to performing experiments using THz radiation are enormous.
One needs not only a THz source, but also an appropriate receiver and an
understanding of many experimental details, ranging from the absorption
characteristics of the atmosphere and common materials, to where to purchase
or construct various simple optics components such as polarizers, lenses, and
waveplates, to a solid understanding of electromagnetic wave propagation,
since diffraction always plays a significant role at THz frequencies. There is
also significant expense, both in terms of time and money, in setting up any
THz apparatus in one’s own lab, even if one is the type of investigator who
enjoys building things.
Because of the enormous barriers to entry into THz science, the community of
users is presently much smaller than the potential based on the scientific
opportunities. Symposia on medical applications of THz radiation are already
attracting overflow crowds at conferences. The size of the community is
increasing with a clear growth potential to support a large THz user’s
network including user facilities. The opportunities are great. The most
important thing we can do is lower research barriers.
A THz User’s Network would leverage the large existing investment in THz
research and infrastructure to considerably grow the size of the THz research
community. The Network would inform the scientific community at large of
opportunities in THz science, bring together segments of the community of THz
researchers who are currently only vaguely aware of one another and lower the
barriers to entry into THz research.
Specific ideas for network activities include disseminating information about
techniques and opportunities in THz science through the worldwide web,
sponsoring sessions about THz technology at scientific conferences,
co-location of conferences from different communities within the THz field,
providing funding for small-scale user facilities at existing centers of
excellence, directing researchers interested in THz science to the most
appropriate technology and/or collaborator, encouraging commercialization of
critical THz components, outreach to raise public awareness of THz science and
technology, and formation of teams to work on problems of common interest,
such as producing higher peak fields or pulse-shaping schemes.
Interagency support is crucial: NIH, NSF, and DOE will all
benefit, and all must be involved. Eventually, the network will provide the
best and most efficient path to defining what new facilities may be needed.
New users of THz methodology will also find it easier to learn about the field
when there is a network.
Defining common goals: During the workshop, the community
articulated several common and unmet technical needs. This list is far from
exhaustive, and it will grow with the network:
1. Higher peak fields.
2. Coverage to 10 THz (or higher) with coherent
broad-band sources.
3. Full pulse-shaping.
4. Excellent stability in sources with the
above characteristics.
5. Easy access to components such as emitters
and receivers,
and for time-domain THz
spectroscopy.
6. Near-field THz microscopy.
7. Sensitive non-cryogenic detectors.
(List of recent BES workshop reports)
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Basic Research Needs for the Hydrogen Economy
This report is based upon the BES Workshop on Hydrogen Production, Storage, and Use, held May 13–15, 2003, to
identify fundamental research needs and opportunities in hydrogen production, storage, and use, with a focus on new, emerging and scientifically
challenging areas that have the potential to have significant impact in science and technologies.
The coupled challenges of a doubling in the world’s energy needs by the year 2050 and the increasing demands for “clean” energy sources that do not add more carbon dioxide and other pollutants to the environment have resulted in increased attention worldwide to the possibilities of a “hydrogen economy” as a long-term solution for a secure energy future.
The hydrogen economy offers a grand vision for energy management in the future.
Its benefits are legion, including an ample and sustainable supply, flexible interchange with existing energy media, a diversity of end uses to produce electricity through fuel cells or to produce heat through controlled combustion, convenient storage for load leveling, and a potentially large reduction in harmful environmental pollutants.
These benefits provide compelling motivation to mount a major, innovative basic research program in support of a broad effort across the applied research, development, engineering, and industrial communities to enable the use of hydrogen as the fuel of the future.
There is an enormous gap between our present capabilities for hydrogen production, storage, and use and those required for a competitive hydrogen economy.
To be economically competitive with the present fossil fuel economy, the cost of fuel cells must be lowered by a factor of 10 or more and the cost of producing hydrogen must be lowered by a factor of 4. Moreover, the performance and reliability of hydrogen technology for transportation and other uses must be improved dramatically.
Simple incremental advances in the present state of the art cannot bridge this gap.
The only hope of narrowing the gap significantly is a comprehensive, long-range program of innovative, high-risk/high-payoff basic research that is intimately coupled to and coordinated with applied programs.
The best scientists from universities and national laboratories and the best engineers and scientists from industry must work in interdisciplinary groups to find breakthrough solutions to the fundamental problems of hydrogen production, storage, and use.
The objective of such a program must not be evolutionary advances but revolutionary breakthroughs in understanding and in controlling the chemical and physical interactions of hydrogen with materials.
The detailed findings and research directions identified by the three panels are presented in this
report. They address the four research challenges for the hydrogen economy outlined by Secretary of Energy Spencer Abraham in his address to the National Hydrogen
Association: (1) dramatically lower the cost of fuel cells for transportation, (2) develop a diversity of sources for hydrogen production at energy costs comparable to those of gasoline, (3) find viable methods of onboard storage of hydrogen for transportation uses, and (4) develop a safe and effective infrastructure for seamless delivery of hydrogen from production to storage to use.
The essence of this report is captured in six cross-cutting research directions that were identified as being vital for enabling the dramatic breakthroughs to achieve lower costs, higher performance, and greater reliability that are needed for a competitive hydrogen economy:
• Catalysis
• Nanostructured Materials
• Membranes and Separations
• Characterization and Measurement Techniques
• Theory, Modeling, and Simulation
• Safety and Environmental Issues
In addition to these research directions, the panels identified biological and bio-inspired science and technology as richly promising approaches for achieving the revolutionary technical advances required for a hydrogen
economy.
(List of recent BES workshop reports)
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Theory and Modeling in Nanoscience
This report is based upon the May 10–11, 2002, workshop conducted jointly by the Basic Energy Sciences Advisory Committee and the Advanced Scientific Computing Advisory Committees to identify challenges and opportunities for theory, modeling, and simulation in nanoscience and nanotechnology and to investigate the growing and promising role of applied mathematics and computer science in meeting those challenges.
During the past 15 years, the fundamental techniques of theory, modeling, and simulation have undergone a revolution that parallels the extraordinary experimental advances on which the new field of nanoscience is based.
This period has seen the development of density functional algorithms, quantum Monte Carlo techniques,
ab initio molecular dynamics, advances in classical Monte Carlo methods and mesoscale methods for soft matter, and fast-multipole and multigrid algorithms.
Dramatic new insights have come from the application of these and other new theoretical capabilities.
Simultaneously, advances in computing hardware increased computing power by four orders of magnitude.
The combination of new theoretical methods together with increased computing power has made it possible to simulate systems with millions of degrees of freedom.
The application of new and extraordinary experimental tools to nanosystems has created an urgent need for a quantitative understanding of matter at the nanoscale.
The absence of quantitative models that describe newly observed phenomena increasingly limits progress in the field.
A clear consensus emerged at the workshop that without new, robust tools and models for the quantitative description of structure and dynamics at the nanoscale, the research community would miss important scientific opportunities in nanoscience.
The absence of such tools would also seriously inhibit widespread applications in fields of
nanotechnology ranging from molecular electronics to biomolecular materials.
To realize the unmistakable promise of theory, modeling, and simulation in overcoming fundamental challenges in nanoscience requires new human and computer resources.
Fundamental Challenges and Opportunities
With each fundamental intellectual and computational challenge that must be met in nanoscience comes opportunities for research and discovery utilizing the approaches of theory, modeling, and simulation.
In the broad topical areas of (1) nano building blocks (nanotubes, quantum dots, clusters, and nanoparticles), (2) complex nanostructures and nano-interfaces, and (3) the assembly and growth of nanostructures, the workshop identified a large number of theory, modeling, and simulation challenges and opportunities.
Among them are:
• to bridge electronic through macroscopic length and time scales
• to determine the essential science of transport mechanisms at the nanoscale
• to devise theoretical and simulation approaches to study nano-interfaces, which
dominate nanoscale systems and are necessarily highly complex and heterogeneous
• to simulate with reasonable accuracy the optical properties of nanoscale structures
and to model nanoscale opto-electronic devices
• to simulate complex nanostructures involving “soft” biologically or organically based
structures and “hard” inorganic ones as well as nano-interfaces between hard and
soft matter
• to
simulate self-assembly and directed self-assembly
• to devise theoretical and simulation approaches to quantum coherence, deco-herence,
and spintronics
• to develop self-validating and benchmarking methods
The Role of Applied Mathematics
Since mathematics is the language in which theory is expressed and advanced, developments in applied mathematics are central to the success of theory, modeling, and simulation for nanoscience, and the workshop identified important roles for new applied mathematics in the above-mentioned challenges. Novel applied mathematics is required to formulate new theory and to develop new computational algorithms applicable to complex systems at the nanoscale.
The discussion of applied mathematics at the workshop focused on three areas that are directly relevant to the central challenges of theory, modeling, and simulation in nano-science: (1) bridging time and length scales, (2) fast algorithms, and (3) optimization and predictability. Each of these broad areas has a recent track record of developments from the applied mathematics community. Recent advances range from fundamental approaches, like mathematical homogenization (whereby reliable coarse-scale results are made possible without detailed knowledge of finer scales), to new numerical algorithms, like the fast-multipole methods that make very large scale molecular dynamics calculations possible. Some of the mathematics of likely interest (perhaps the most important mathematics of interest) is not fully knowable at the present, but it is clear that collaborative efforts between scientists in nanoscience and applied mathematicians can yield significant advances central to a successful national nanoscience initiative.
The Opportunity for a New Investment
The consensus of the workshop is that the country’s investment in the national nano-science initiative will pay greater scientific dividends if it is accelerated by a new investment in theory, modeling, and simulation in nanoscience. Such an investment can stimulate the formation of alliances and teams of experimentalists, theorists, applied mathematicians, and computer and computational scientists to meet the challenge of developing a broad quantitative understanding of structure and dynamics at the nanoscale.
The Department of Energy is uniquely situated to build a successful program in theory, modeling, and simulation in nano-science. Much of the nation’s experimental work in nanoscience is already supported by the Department, and new facilities are being built at the DOE national laboratories. The Department also has an internationally regarded program in applied mathematics, and much of the foundational work on mathematical modeling and computation has emerged from DOE activities. Finally, the Department has unique resources and experience in high performance computing and algorithms. The combination of these areas of expertise makes the Department of Energy a natural home for nanoscience theory, modeling, and
simulation.
(List of recent BES workshop reports)
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Opportunities for Catalysis in the 21st Century
This report is based upon a Basic Energy Sciences Advisory Committee
subpanel workshop
that was held May 14–16, 2002, to identify research directions to better understand how to design catalyst structures to control catalytic activity and selectivity.
Chemical catalysis affects our lives in myriad ways. Catalysis provides a means of changing the rates at which chemical bonds are formed and broken and of controlling the yields of chemical reactions to increase the amounts of desirable products from these reactions and reduce the amounts of undesirable ones. Thus, it lies at the heart of our quality of life: The reduced emissions of modern cars, the abundance of fresh food at our stores, and the new pharmaceuticals that improve our health are made possible by chemical reactions controlled by catalysts. Catalysis is also essential to a healthy economy: The petroleum, chemical, and pharmaceutical industries, contributors of $500 billion to the gross national product of the United States, rely on catalysts to produce everything from fuels to “wonder drugs” to paints to cosmetics.
Today, our Nation faces a variety of challenges in creating alternative fuels, reducing harmful by-products in manufacturing, cleaning up the environment and preventing future pollution, dealing with the causes of global warming, protecting citizens from the release of toxic substances and infectious agents, and creating safe pharmaceuticals. Catalysts are needed to meet these challenges, but their complexity and diversity demand a revolution in the way catalysts are designed and used.
This revolution can become reality through the application of new methods for synthesizing and characterizing molecular and material systems. Opportunities to understand and predict how catalysts work at the atomic scale and the nanoscale are now appearing, made possible by breakthroughs in the last decade in computation, measurement techniques, and imaging and by new developments in catalyst design, synthesis, and evaluation.
A Grand Challenge
In May 2002, a workshop entitled “Opportunities for Catalysis Science in the 21st Century” was conducted in Gaithersburg, Maryland. The impetus for the workshop grew out of a confluence of factors: the continuing importance of catalysis to the Nation’s productivity and security, particularly in the production and consumption of energy and the associated environmental consequences, and the emergence of new research tools and concepts associated with nanoscience that can revolutionize the design and use of catalysts in the search for optimal control of chemical transformations. While research opportunities of an extraordinary variety were identified during the workshop, a compelling, unifying, and fundamental challenge became clear. Simply stated,
the Grand Challenge for catalysis science in the 21st century is to understand how to design catalyst structures to control catalytic activity and selectivity.
The Present Opportunity
In his address to the 2002 meeting of the American Association for the Advancement of Science, Jack Marburger, the President’s Science Advisor, spoke of the revolution that will result from our emerging ability to achieve an atom-by-atom understanding of matter and the
subsequent unprecedented ability to design and construct new materials with properties that are not found in nature. “ The revolution I am describing,” he said, “ is one in which the notion that everything is made of atoms finally becomes operational…. We can actually see how the machinery of life functions, atom by atom. We can actually build atomic-scale structures that interact with biological or inorganic systems and alter their functions. We can design new tiny objects ‘from scratch’ that have unprecedented optical, mechanical, electrical, chemical, or biological properties that address needs of human society.”
Nowhere else can this revolution have such an immediate payoff as in the area of catalysis. By investing now in new methods for design, synthesis, characterization, and modeling of catalytic materials, and by employing the new tools of nanoscience, we will achieve the ability to design and build catalytic materials atom by atom, molecule by molecule, nanounit by nanounit.
The Importance of Catalysis Science to DOE
For the present and foreseeable future, the major source of energy for the Nation is found in chemical bonds. Catalysis affords the means of changing the rates at which chemical bonds are formed and broken. Catalysis also allows chemistry of extreme specificity, making it possible to select a desired product over an undesired one. Materials and materials properties lie at the core of almost every major issue that the U.S. Department of Energy (DOE) faces, including energy, stockpile stewardship, and environmental remediation. Much of the synthesis of new materials is certainly going to happen through catalysis. When scientists and engineers understand how to design catalysts to control catalytic chemistry, the effects on energy production and use and on the creation of exciting new materials will be profound.
A Recommendation for Increased Federal Investment in Catalysis Research
We are approaching a renaissance in catalysis science in this country. With the availability of exciting new laboratory tools for characterization, new designer approaches to synthesis, advanced computational capabilities, and new capabilities at user facilities, we have unparalleled potential for making significant advances in this vital and vibrant field. The convergence of the scientific disciplines that is a growing trend in the catalysis field is spawning new ideas that reach beyond conventional thinking.
This revolution unfortunately comes at a time when industry has largely abandoned its support of basic research in catalysis. As the only Federal agency that supports catalysis as a discipline, DOE is uniquely positioned to lead the revolution. Our economy and our quality of life depend on catalytic processes that are efficient, clean, and effective. An increased investment in catalysis science in this country is not only important, it is essential.
Successful research ventures in this area will have an impact on all levels of daily life, leading to enhanced energy efficiency for a range of fuels, reductions in harmful emissions, effective synthesis of new and improved drugs, enhanced homeland security and stockpile stewardship, and new materials with tailored properties. Federal investment is vital for building the scientific workforce needed to address the challenging issues that lie ahead in this field — a workforce that comprises our best and brightest scientists, developing creative new ideas and approaches. This investment is also vital to ensuring that we have the best scientific tools possible for exploiting creative ideas, and that our scientists have ready access to these experimental and computational tools. These tools include both state-of-the-art instrumentation in individual investigator laboratories and unique instrumentation that is only available, because of its size and cost, at DOE’ s national user facilities.
(List of recent BES workshop reports)
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Biomolecular Materials
This report is based upon the January 13–15, 2002, workshop sponsored by the Basic Energy Sciences Advisory Committee to explore the potential impact of biology on the physical sciences, in particular the materials and chemical sciences.
Twenty-two scientists from around the nation and the world met to discuss the way that the molecules, structures, processes and concepts of the biological world could be used or mimicked in designing novel materials, processes or devices of potential practical significance. The emphasis was on basic research, although the long-term goal is, in addition to increased knowledge, the development of applications to further the mission of the Department of Energy.
The charge to the workshop was to identify the most important and potentially fruitful areas of research in the field of Biomolecular Materials and to identify challenges that must be overcome to achieve success.
This report summarizes the response of the workshop participants to this charge, and provides, by way of example, a description of progress that has been made in selected areas of the field.
The participants felt that a DOE program in this area should focus on the development of a greater understanding of the underlying biology, and tools to manipulate biological systems both
in vitro and in vivo rather than on the attempted identification of narrowly defined applications or devices.
The field is too immature to be subject to arbitrary limitations on research and the exclusion of areas that could have great impact.
These limitations aside, the group developed a series of recommendations.
Three major areas of research were identified as central to the exploitation of biology for the physical sciences:
1) Self Assembled, Templated and Hierarchical Structures; 2) The Living Cell in Hybrid Materials Systems; and 3) Biomolecular Functional
Systems.
Workshop participants also discussed the challenges and impediments that stand in the way of our attaining the goal of fully exploiting biology in the physical sciences. Some are cultural, others are scientific and technical.
Recommendations from the report are:
Program Relevance. In view of what has recently developed into a generally recognized opinion that biology offers a rich source of structures, functions and inspiration for the development of novel materials, processes and devices support for this research should be a component of the broad Office of Basic Energy Sciences Program.
Broad Support. The field is in its early stages and is not as well defined as other areas. Thus, although it is recommended that support be focused in the three areas identified in this report, it should be broadly applied. Good ideas in other areas proposed by investigators with good track records should be supported as well. There should not be an emphasis on “picking winning applications” because it is simply too difficult to reliably identify them at this time.
Support of the Underlying Biology. Basic research focused on understanding the biological structures and processes in areas that show potential for applications supporting the DOE mission should be supported.
Multidisplinary Teams. Research undertaken by multidisciplinary teams across the spectrum of materials science, physics, chemistry and biology should be encouraged but not artificially arranged.
Training. Research that involves the training of students and postdocs in multiple disciplines, preferably co-advised by two or more senior investigators representing different relevant disciplines, should be encouraged without sacrificing the students’ thorough studies within the individual disciplines.
Long-Term Investment. Returns, in terms of functioning materials, processes or devices should not be expected in the very short term, although it can reasonably be assumed that applications will, as they have already, arise
unexpectedly.
(List of
recent BES workshop reports)
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Basic Research Needs To Assure A Secure Energy Future
This report is based upon a Basic Energy Sciences Advisory Committee workshop
that was held in October 2002 to assess the basic research needs for energy technologies to assure a reliable, economic, and environmentally sound energy supply for the future. The workshop discussions produced a total of 37 proposed research directions.
Current projections estimate that the energy needs of the world will more than double by the year 2050. This is coupled with increasing demands for “clean” energy – sources of energy that do not add to the already high levels of carbon dioxide and other pollutants in the environment. These coupled challenges simply cannot be met by existing technologies. Major scientific breakthroughs will be required to provide reliable, economic solutions.
The results of the BESAC workshop are a compilation of 37 Proposed Research Directions. At a higher level, these fell into ten general research areas, all of which are multidisciplinary in nature:
• Materials Science to Transcend Energy Barriers
• Energy Biosciences
• Basic Research Towards the Hydrogen Economy
• Innovative Energy Storage
• Novel Membrane Assemblies
• Heterogeneous Catalysis
• Fundamental Approaches to Energy Conversion
• Basic Research for Energy Utilization Efficiency
• Actinide Chemistry and Nuclear Fuel Cycles
• Geosciences
Nanoscale science, engineering, and technology were identified as cross-cutting areas where research may provide solutions and insights to long-standing technical problems and scientific questions. The need for developing quantitative predictive models was also identified in many cases, and this requires better understanding of the underlying fundamental mechanisms of the relevant processes. Often this in turn requires characterization with very high physical, chemical, structural, and temporal precision: DOE’s existing world-leading user facilities currently provide these capabilities, and these capabilities must be continuously enhanced and new ones developed. In addition, requirements for theory, modeling, and simulation will demand advanced computational tools, including high-end computer user facilities. All the participants agreed that the education of the next generation of research scientists is of crucial importance; and this should include making the importance of the energy security issue clear to everyone.
It is clear that assuring the security of the energy supply for the U.S. over the next few decades will present major problems. There are a number of reasons for this. The most important of these is the current reliance on fossil fuels for a high proportion of the energy, of which a significant fraction is imported. The Developing World countries will have greatly increased needs for energy, in part because of the expected population increase, and in part because of the increase in their presently very low standards of living. A second problem is related to concerns over the environmental effects of the use of fossil fuels. Third, the peaking of the production of fossil fuels is likely within the next several decades. For these reasons, it is very important that the U.S. undertakes a vigorous research and development program to address the issues identified in this report.
There are a number of actions that can help in the nearer term: increased efficiency in the conversion and use of energy; increased conservation; and aggressive environmental control requirements. However, while these may delay the major impact, they will not in the longer run provide the assured energy future that the U.S. requires. It is also clear that there is no single answer to this problem. There are several options that are available at the moment, and many – or indeed all – of them must be pursued.
Basic research will make an important contribution to the solution to this problem by providing the basis on which entities which include DOE’s applied missions programs will develop new technological approaches; and by leading to the discovery of new concepts. The time between the basic research and its contribution to new or significantly improved technical solutions that can make major contributions to the future energy supply is often measured in decades. Major new discoveries are needed, and these will largely come from basic research programs.
It is clear from the analysis presented in this report that there are a number of opportunities. Essentially all of these are interdisciplinary in character. The Office of Basic Energy Sciences should review its current research portfolio to assess how it is contributing to the research directions proposed by this study.
BESAC expects, however, that a much larger effort will be needed than the current BES program. The magnitude of the energy challenge should not be underestimated. With major scientific discoveries and development of the underlying knowledge base, we must enable vast technological changes in the largest industry in the world (energy), and we must do it quickly. If we are successful, we will both assure energy security at home and promote peace and prosperity worldwide.
Recommendation: Considering the urgency of the energy problem, the magnitude of the needed scientific breakthroughs, and the historic rate of scientific discovery, current efforts will likely be too little, too late. Accordingly, BESAC believes that a new national energy research program is essential and must be initiated with the intensity and commitment of the Manhattan Project, and sustained until this problem is solved.
BESAC recommends that BES review its research activities and user facilities to make sure they are optimized for the energy challenge, and develop a strategy for a much more aggressive program in the
future.
(List of recent BES workshop reports)
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Basic Research Needs for Countering Terrorism
This report documents
the results of the Department of Energy, Office of Basic Energy Sciences
(BES) Workshop on Basic Research Needs to Counter Terrorism.
This two-day Workshop, held in Gaithersburg, MD, February 28–March 1, 2002, brought together BES research participants and experts
familiar with counter-terrorism technologies, strategies, and policies.
The purpose of the workshop was to: (1) identify direct connections
between technology needs for countering terrorism and the critical,
underlying science issues that will impact our ability to address those
needs and (2) recommend investment strategies that will increase the
impact of basic research on our nation’s efforts to counter terrorism.
The workshop focused on
science and technology challenges associated with our nation’s need to
detect, prevent, protect against, and respond to terrorist attacks
involving Radiological and Nuclear, Chemical, and Biological threats.
While the organizers and participants of this workshop recognize
that the threat of terrorism is extremely broad, including food and water
safety as well as protection of our public infrastructure, we necessarily
limited the scope of our discussions to the principal weapons of mass
destruction.
In order to set the
stage for the discussions of critical science and technology challenges,
the workshop began with keynote and plenary lectures that provided a
realistic context for understanding the broad challenges of countering
terrorism. The plenary
speakers emphasized the socio-political complexity of terrorism problems,
reinforced the need for basic research in addressing these problems, and
provided critical advice on how basic research can best contribute to our
nation’s needs. Their
advice highlighted the need to:
•
Invest
Strategically – Focus on Cross-Cutting
Research that has the
potential to have an impact on a broad set of technology needs, thereby
providing the greatest return on the research investment.
•
Build Team Efforts
– Countering terrorism will require broad, collaborative teams.
The research community should focus on:
(1) Research
Environments and Infrastructures that encourage and enable
cross-disciplinary science and technology teams to explore and integrate
new scientific discoveries and (2) Exploring Relationships
with Other Programs that
will strengthen connections between new scientific advances and those
groups responsible for technology development and implementation.
•
Consider Dual Use
– Identify areas of research that present significant Dual-Use
Opportunities for application to countering terrorism and other
complementary technology needs.
The during the
workshop, participants identified several critical technology needs and
the underlying science challenges that, if met, can help to reduce the
threat of terrorist attacks in the United States.
Some of the key technology needs and limitations that were
identified include:
Detection – Nonintrusive,
stand-off, and imaging detection systems; sampling from complex
backgrounds and environments; inexpensive and field-deployable sensor
systems; highly selective and ultra-sensitive detectors; early warning
triggers for continuous monitoring
Prevention
– Methods and materials to control, track, and reduce the availability
of hazardous materials; techniques to rapidly characterize and attribute
the source of terrorist threats
Protection
– Personal protective equipment; light-weight barrier materials and
fabrics; filtration systems; explosive containment structures; methods to
protect people, animals, crops, and public spaces
Response – Coupled
models and measurements that can predict fate and transport of toxic
materials including pre-event background data; pre-symptomatic and point
of care medical diagnostics; methods to immobilize and neutralize
hazardous materials including self-cleaning and self-decontaminating
surfaces
The workshop
discussions of these technology needs and the underlying science
challenges are fully documented in the major sections of this report.
The results of these discussions, combined with the broad
perspective and advice from our plenary speakers, were used to develop a
set of high-level workshop recommendations.
The following recommendations are offered to help guide our
nation’s basic research investments in order to maximize our ability to
reduce the threat of terrorism.
•
We recommend
continuing or increasing funding for a selected set of research directions
that are identified in the Workshop Summary and Recommendations (Section
5) of this report. These areas of research underpin many of the technologies
that have high probability to impact our nation’s ability to counter
terrorism.
•
New programs should be
supported to stimulate the formation of, and provide needed resources for,
cross-disciplinary and multi-institutional teams of scientists and
technologists that are needed to address these critical problems.
An important component of this strategy is investment in DOE
national laboratories and user facilities because they can provide an
ideal environment to carry out this highly collaborative work.
•
Governmental
organizations and agencies should explore their complementary goals and
capabilities and, where appropriate, work to develop agreements that
facilitate the formation of multi-organizational teams and the sharing of
research and technology capabilities that will improve our nation’s
ability to counter the threat of terrorism.
•
Increased emphasis
should be placed on identifying dual-use applications for key
counter-terrorism technologies. Efforts
should be focused on building partnerships between government, university,
and industry to capitalize on these opportunities.
In summary, this
workshop made significant progress in identifying the basic research needs
and in outlining a strategy to enhance the research community’s ability
to impact our nation’s counter-terrorism needs.
We wish to acknowledge the enthusiasm and hard work of all the
workshop participants. Their
extraordinary contributions were key to the success of this workshop, and
their dedication to this endeavor provides strong evidence that the basic
research community is firmly committed to supporting our nation’s goal
of reducing the threat of terrorism in the United States.
(List of recent BES workshop reports)
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Complex Systems: Science for the 21st Century
This report is based upon a BES workshop, March
5–6, 1999, which was designed to help define new scientific directions related to complex
systems in order to create new understanding about the nano
world and complicated, multicomponent structures.
As we look further into this century, we find science and technology at yet another threshold: the study of simplicity will give way to the study of "complexity" as the unifying theme.
The triumphs of science in the past century, which improved our lives immeasurably, can be described as elegant solutions to problems reduced to their ultimate simplicity.
We discovered and characterized the fundamental particles and the elementary excitations in matter and used them to form the foundation for interpreting the world around us and for building devices to work for us.
We learned to design, synthesize, and characterize small, simple molecules and to use them as components of, for example, materials, catalysts, and pharmaceuticals. We developed tools to examine and describe these "simple" phenomena and
structures.
The new millennium will take us into the world of complexity.
Here, simple structures interact to create new phenomena and assemble themselves into devices. Here also, large complicated structures can be designed atom by atom for desired characteristics.
With new tools, new understanding, and a developing convergence of the disciplines of physics, chemistry, materials science, and biology, we will build on our 20th century successes and begin to ask and solve questions that were, until the 21st century, the stuff of science
fiction.
Complexity takes several forms. The workshop participants identified five emerging themes around which research could be
organized.
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Collective Phenomena —
Can we achieve an understanding of collective phenomena to create materials with novel, useful properties? We already see the first examples of materials with properties dominated by collective
phenomena — phenomena that emerge from the interactions of the components of the material and whose behavior thus differs significantly from the behavior of those individual components.
In some cases collective phenomena can bring about a large response to a small
stimulus — as seen with colossal magnetoresistance, the basis of a new generation of recording memory media.
Collective phenomena are also at the core of the mysteries of such materials as the high-temperature
superconductors.
Materials by Design —
Can we design materials having predictable, and yet often unusual properties?
In the past century we discovered materials, frequently by chance, determined their properties, and then discarded those materials that did not meet our needs.
Now we will see the advent of structural and compositional freedoms that will allow the design of materials having specific desired characteristics directly from our knowledge of atomic structure.
Of particular interest are "nanostructured" materials, with length scales between 1 and 100 nanometers. In this regime, dimensions "disappear," with zero-dimensional dots or nanocrystals, one-dimensional wires, and two-dimensional films, each with unusual properties distinctly different from those of the same material with "bulk" dimensions.
We could design materials for lightweight batteries with high storage densities, for turbine blades that can operate at 2500°C, and perhaps even for quantum
computing.
Functional Systems — Can we design and construct multicomponent molecular devices and machines?
We have already begun to use designed building blocks to create self-organized structures of previously unimagined complexity.
These will form the basis of systems such as nanometer-scale chemical factories, molecular pumps, and sensors.
We might even stretch and think of self-assembling electronic/photonic
devices.
Nature’s Mastery — Can we harness, control, or mimic the exquisite complexity of Nature to create new materials that repair themselves, respond to their environment, and perhaps even evolve?
This is, perhaps, the ultimate goal. Nature tells us it can be done and provides us with examples to serve as our models.
We learn about Nature’s design rules and try to mimic green plants which capture solar energy, or genetic variation as a route to "self-improvement" and optimized function.
T hese concepts may seem fanciful, but with the revolution now taking place in biology, progressing from DNA sequence to structure and function, the possibilities seem endless.
Nature has done it. Why can’t we?
New Tools — Can we develop the characterization instruments and the theory to help us probe and exploit this world of complexity?
Radical enhancement of existing techniques and the development of new ones will be required for the characterization and visualization of structures, properties, and
functions — from the atomic, to the molecular, to the nanoscale, to the macroscale.
Terascale computing will be necessary for the modeling of these complex systems. |
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Now is the time. We can now do this research, make these breakthroughs, and enhance our lives as never before imagined. The work of the past few decades has taken us to this point, solving many of the problems that underlie these challenges, teaching us how to approach problems of complexity, giving us the confidence needed to achieve these goals. This work also gave us the ability to compute on our laps with more power than available to the Apollo astronauts on their missions to the moon. It taught us to engineer genes, "superconduct" electricity, visualize individual atoms, build "plastics" ten times stronger than steel, and put lasers on chips for portable CD players. We are ready to take the next
steps.
Complexity pays dividends. We think of simple silicon for semiconductors, but our CD players depend on dozens of layers of semiconductors made of aluminum, gallium, and arsenic. Copper conducts electricity and iron is magnetic. Superconductors and giant magnetoresistive materials have eight or more elements, all of which are essential and interact with one another to produce the required proper-ties. Nature, too, shows us the value of complexity. Hemoglobin, the protein that transports oxygen from the lungs to, for example, the brain, is made up of four protein subunits which interact to vastly increase the efficiency of delivery. As individual subunits, these proteins cannot do the job.
The new program. The very nature of research on complexity makes it a "new millennium" program. Its foundations rest on four pillars: physics, chemistry, materials science, and biology. Success will require an unprecedented level of inter-disciplinary collaboration. Universities will need to break down barriers between established departments and encourage the development of teams across disciplinary lines. Interactions between universities and national laboratories will need to be increased, both in the use of the major facilities at the laboratories and also through collaborations among research programs. Finally, understanding the interactions among components depends on understanding the components themselves. Although a great deal has been accomplished in this area in the past few decades, far more remains to be done. A complexity program will complement the existing programs and will ensure the success of both. The benefits are, as they have been at the start of all previous scientific "revolutions," beyond anything we can now foresee.
(List of recent BES workshop reports)
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Nanoscale Science, Engineering and Technology Research Directions
This report illustrates the wide range of research opportunities and challenges in nanoscale science, engineering and technology. It was prepared in
1999 in connection with the interagency national research initiative on nanotechnology.
The principal missions of the Department of Energy (DOE) in Energy, Defense, and Environment will benefit greatly from future developments in nanoscale science, engineering and technology.
For example, nanoscale synthesis and assembly methods will result in significant improvements in solar energy conversion; more energy-efficient lighting; stronger, lighter materials that will improve efficiency in transportation; greatly improved chemical and biological sensing; use of low-energy chemical pathways to break down toxic substances for environmental remediation and restoration; and better sensors and controls to increase efficiency in manufacturing.
The DOE’s Office of Science has a strong focus on nanoscience discovery, the development of fundamental scientific understanding, and the conversion of these into useful technological solutions. A key challenge in nanoscience is to understand how deliberate tailoring of materials on the nanoscale can lead to novel and enhanced functionalities. The DOE National Laboratories are already making a broad range of contributions in this area. The enhanced properties of nanocrystals for novel catalysts, tailored light emission and propagation, and supercapacitors are being explored, as are hierachical nanocomposite structures for chemical separations, adaptive/responsive behavior and impurity gettering. Nanocrystals and layered structures offer unique opportunities for tailoring the optical, magnetic, electronic, mechanical and chemical properties of materials. The Laboratories are currently synthesizing layered structures for electronics/photonics, novel magnets and surfaces with tailored hardness. This report supplies numerous other examples of new properties and functionalities that can be achieved through nanoscale materials control. These include:
• Nanoscale layered materials that can yield a four-fold increase in the performance of permanent magnets;
• Addition of aluminum oxide nanoparticles that converts aluminum metal into a material with wear resistance equal to that of the best bearing steel;
• New optical properties achieved by fabricating photonic band gap superlattices to guide and switch optical signals with nearly 100% transmission, in very compact architectures;
• Layered quantum well structures to produce highly efficient, low-power light sources and photovoltaic cells;
• Novel optical properties of semiconducting nanocrystals that are used to label and track molecular processes in living cells;
• Novel chemical properties of nanocrystals that show promise as photocatalysts to speed the breakdown of toxic wastes;
• Meso-porous inorganic hosts with self-assembled organic monolayers that are used to trap and remove heavy metals from the environment;
and
• Meso-porous structures integrated with micromachined components that are used to produce high-sensitivity and highly selective chip-based detectors of chemical warfare agents.
These and other nanostructures are already recognized as likely key components of 21st century optical communications, printing, computing, chemical sensing and energy conversion technologies.
The DOE is well prepared to make major contributions to developing nanoscale scientific understanding, and ultimately nanotechnology, through its materials characterization, synthesis, in situ diagnostic and computing capabilities. The DOE and its National Laboratories maintain a large array of major national user facilities that are ideally suited to nanoscience discovery and to developing a fundamental understanding of nanoscale processes. Synchrotron and neutron sources provide exquisite energy control of radiation sources that are able to probe structure and properties on length scales ranging from Ångstroms to millimeters. Scanning Probe Microscope (SPM) and Electron Microscopy facilities provide unique capabilities for characterizing nanoscale materials and diagnosing processes. DOE also maintains synthesis and prototype manufacturing centers where fundamental and applied research, technology development and prototype fabrication can be pursued simultaneously. Finally, the large computational facilities at the DOE National Laboratories can be key contributors in nanoscience discovery, modeling and understanding.
In order to increase the impact of major DOE facilities on the national nanoscience and technology initiative, it is proposed to establish several new Nanomaterials Research Centers. These Centers are intended to exploit and be associated with existing radiation sources and materials characterization and diagnostic facilities at DOE National Laboratories. Each Center would focus on a different area of nanoscale research, such as materials derived from or inspired by nature; hard and crystalline materials, including the structure of macromolecules; magnetic and soft materials, including polymers and ordered structures in fluids; and nanotechnology integration. The Nanomaterials Research Centers will facilitate interdisciplinary research and provide an environment where students, faculty, industrial researchers and national laboratory staff can work together to rapidly advance nanoscience discovery and its application to nanotechnology. Establishment of these Centers will permit focusing DOE resources on the most important nanoscale science questions and technology needs, and will ensure strong coupling with the national nanoscience initiative. The synergy of these DOE assets in partnership with universities and industry will provide the best opportunity for nanoscience discoveries to be converted rapidly into technological advances that will meet a variety of national needs and enable the United States to reap the benefits of a technological revolution.
(List of recent BES workshop reports)
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