Each of these technology sections contains a sub-section describing the current portfolio, where the technology descriptions include an Internet link to the updated version of the CCTP report, Technology Options for the Near and Long Term (CCTP 2005). 2

5.1 Low-Emission, Fossil-Based Fuels and Power

Potential Role of Technology

Technology Strategy

Current Portfolio

Significant reductions in atmospheric CO₂emissions have been demonstrated via efficiency improvements. Current Integrated Gasification Combined Cycle (IGCC) systems average power plant efficiencies are about 40-42 percent; increasing efficiencies to 48-52 percent in the mid term and 60 percent by 2020 (with the integration of fuel cell technology), will nearly halve emissions of CO₂per unit of electricity, relative to pulverized-coal-based power plants which have efficiencies of 30-35 percent (Figure 5-4). Development and deployment of CO₂capture and storage technology could reduce atmospheric emissions to near-zero levels through 2100. Recent R&D activities have focused on IGCC plants, with two U.S. IGCC demonstration plants now in operation.

The research program goal in the Advanced Power Systems area is to increase efficiency of new systems to levels ranging from 48-52 percent by 2010, and 60 percent by 2020, while also achieving an overall electricity production cost that is between 75 percent and 90 percent of current pulverized-coal-based power generation. In addition, emissions of criteria pollutants are targeted to be much less than one-tenth of current new source performance standards. 5

Figure 5-3 A fully integrated coal-based energy complex will have the ability to co-produce electricity, hydrogen, fuels and chemicals with little or no CO₂emissions. (Source: DOE 2004)

In the near and mid terms, fuel cell cost reductions could enable the widespread deployment of natural-gas-fueled distributed generation in gas-only, CHP, and fuel cell applications. In the mid- to long-term, this technology, along with others being developed as part of the Distributed Generation effort, will also support coal-based FutureGen/central-station applications. The goal is to develop a modular power system with lower cost and significantly lower carbon dioxide emissions than current plants. Examples of current R&D projects in this area include: (1) low-cost fuel cell systems development; (2) high-temperature fuel cell scale-up and aggregation for fuel cell turbine (FCT) hybrid application; and (3) hybrid systems and component demonstration.

Research program goals in the natural gas fuel cell and hybrid power systems include demonstrating a gas aggregated fuel cell module larger than 250 kW that can run on coal synthetic gas (syngas), while also reducing the costs of the Solid-State Energy Conversion Alliance fuel cell power system to $400/kW by 2010. In addition, by 2012-2015, the program aims to: (1) demonstrate a megawatt-class hybrid system at FutureGen with an overall system efficiency of 50 percent on coal syngas; and (2) integrate optimized turbine systems into zero-emission power plants. 6

Near-Zero Atmospheric Emission Power and hydrogen coproduction research goals target a 10-year demonstration project (FutureGen) to create the world's first coal-based, near-zero atmospheric emissions electricity and hydrogen power plant. The near-term goals of the program are to: (1) design, by 2010, a near-term coproduction plant, configured at a size of 275-MW, which would be suitable for commercial deployment; (2) demonstrate pilot-scale reactors using ceramic membranes for oxygen separation and hydrogen recovery; and (3) demonstrate a $400/kW solid-oxide fuel cell. 7

Figure 5-4 Advanced Gas Turbines can increase efficiencies in combined-cycle systems to 60 percent, while also reducing the cost of electricity production. Courtesy: DOE/NETL

Carbon emissions from fossil-fuel-based power systems can be reduced in the near term principally by improving process efficiency and, in the longer term, via more advanced system components, such as high-efficiency fuel cells. In both the near and long terms, incorporating CO₂capture into the systems' processes, accompanied by long-term CO₂storage, will be required to achieve low or near-zero atmospheric emissions from these energy sources. Current research activities focus on: (1) ion transport oxygen separation membranes; (2) hydrogen separation membranes; and (3) early-entrance coproduction plant designs. These activities are discussed in more detail in Chapter 6.

Future Research Directions

Hydrogen

As discussed above, in a long-term future characterized by low or near-net-zero emissions of GHGs, global energy primary supply can continue its reliance on fossil fuels, provided there are suitable means for capturing and storing the resulting emissions of CO₂. Alternatively, the world could increase reliance on low-carbon and nonfossil energy sources. These approaches share a need for carbonless energy carriers, such as electricity or some alternative, to store and deliver energy on demand to end users. Electricity is increasingly the carbonless energy carrier of choice for stationary energy consumers, but hydrogen could prove to be an attractive carrier for the transportation sector (e.g., highway vehicles and aircraft), as well as stationary applications. If successful, hydrogen could enable reductions in petroleum use and potentially eliminate concomitant air pollutants and CO₂emissions on a global scale.

Today, hydrogen is used in various chemical processes and is made largely from natural gas, producing CO₂emissions. However, hydrogen can be produced in a variety of ways that do not emit CO₂, including renewable energy-based electrolysis; various biological and chemical processes; water shift reactions with coal and natural gas, accompanied by CO₂capture and storage; thermal and electrolytic processes using nuclear energy; and direct photoconversion. Hydrogen can be stored as a pressurized gas or cryogenic liquid, or absorbed within metal hydride powders or physically adsorbed onto carbon-based nanostructures. If progress can be made on a number of technical fronts, so that costs of producing hydrogen are reduced, hydrogen could play a valuable enabling and synergistic role in heat and power generation, transportation, and energy end use.

Potential Role of Technology

Like electricity, the life-cycle GHG emissions associated with hydrogen use would vary depending on the method to produce, store, and distribute it. Hydrogen can be generated at various scales, including central plants, fuel stations, businesses, homes, and perhaps onboard vehicles. In principle, the diversity of scales, methods, and sources of production make hydrogen a highly versatile energy carrier, capable of transforming transportation (and potentially other energy services) by enabling compatibility with many primary energy sources. This versatility opens up possibilities for long-term dynamic optimization of CO₂emissions, technology development lead times, economics, and other factors. In a future "hydrogen economy," hydrogen may ultimately serve as a means of linking energy sources to energy uses in ways that are more flexible, secure, reliable, and responsive to consumer demands than today, while also integrating the transportation and electricity markets.

While its simple molecular structure makes hydrogen an efficient synthetic fuel to produce, use, and/or convert to electricity, the storage and delivery of hydrogen are more challenging than for most fuels. Consequently, most hydrogen today is produced at or near its point of use, consuming other fuels (e.g., natural gas) that are easier to handle and distribute.

Large hydrogen demands at petroleum refineries or ammonia (NH3) synthesis plants can justify investment in dedicated hydrogen pipelines, but smaller or variable demands for hydrogen are usually met more economically by truck transport of compressed gaseous hydrogen or cryogenic and liquefied hydrogen produced by steam methane reforming. These methods have evolved over decades of industrial experience, with hydrogen as a niche chemical commodity, produced in amounts (8 billion kg hydrogen/yr) equivalent to about 1 percent (approximately 1 EJ per year) of current primary energy use in the United States. For hydrogen use to scale up from its current position to a global carbonless energy carrier (alongside electricity), new energetically and economically efficient technical approaches would be required for hydrogen delivery, storage, and production.

Hydrogen production can be a value-added complement to other advanced climate change technologies, such as those aimed at the use of fossil fuels or biomass with CO₂capture and storage. As such, hydrogen may be a key and enabling component for full deployment of carbonless electricity technologies (advanced fission, fusion, and/or intermittent renewables).

Figure 5-5 Fuel cells use the chemical energy of hydrogen and oxygen from air to produce electricity without combustion. Courtesy: DOE/NREL, Credit � Matt Stiveson

In the near term, initial deployment of hydrogen fleet vehicles and distributed power systems may provide early adoption opportunities and demonstrate the capabilities of the existing hydrogen delivery and on-site production infrastructure. This will also contribute in other ways, such as improving urban air quality and strengthening electricity supply reliability. This phase of hydrogen use may also serve as a commercial proving ground for advanced distributed hydrogen production and conversion technologies using existing storage technology, both stationary and vehicular.

In the mid term, light-duty vehicles likely will be the first large mass market (10-15 EJ per year in the United States) for hydrogen. Fuel cells may be particularly attractive in automobiles, given their efficiency versus load characteristics and typical driving patterns (Figure 5-5). Hydrogen production for this application could occur either in large centralized plants or using distributed production technologies on a more localized level-most probably the latter.

In the long term, production technologies must be able to produce hydrogen at a price competitive with gasoline for bulk commercial fuel use in automobiles, freight trucks, aircraft, rail, and ships. This would require efficient production means and large quantities of reasonable-cost energy supplies, perhaps from coal with CO₂sequestration, advanced nuclear power (high-efficiency electrolysis and thermochemical decomposition of water), fusion energy, renewables (wind-powered electrolysis, direct conversion of water via sunlight, and high-temperature conversion of water using concentrated solar power), or a variety of methods using biomass. Other important factors in the long term include the cost of hydrogen storage and transportation. Finally, advances in basic science associated with direct water-splitting and solid-state hydrogen storage could possibly permit even lower-cost hydrogen production and safer storage, delivery, and utilization in the context of low or near-net-zero emission futures for transportation and electricity generation.

Technology Strategy

The International Partnership for the Hydrogen Economy (IPHE) was formed in November 2003 among 15 countries (Australia, India, Brazil, Italy, Canada, Japan, China, Republic of Korea, Norway, France, Russia, Germany, United Kingdom, United States, and Iceland) and the European Commission. The IPHE provides a mechanism to organize, evaluate, and coordinate multinational research, development, and deployment programs that advance the transition to a global hydrogen economy. The partnership leverages national resources, brings together the world's best intellectual skills and talents, and develops interoperable technology standards.

The IPHE has reviewed actions being pursued jointly by participating countries and is identifying additional actions to advance research, development, and deployment of hydrogen production, storage, transport, and distribution technologies; fuel cell technologies; common codes and standards for hydrogen fuel utilization; and coordination of international efforts to develop a global hydrogen economy. More about the IPHE.

The Department of Energy's Hydrogen Fuel Cells and Infrastructure Technologies Program plans to research, develop, and demonstrate the critical technologies (and implement codes and standards for safe use) needed for hydrogen light-duty vehicles (Figure 5-6). The program operates in cooperation with automakers and related parties experienced in refueling infrastructure to develop technology necessary to enable a commercialization decision by 2015 (DOE 2005). Current research program goals call for validation by 2015 of technology for:

• Hydrogen storage systems enabling minimum 300-mile vehicle range while meeting identified packaging, cost, and performance requirements;

• Hydrogen production to safely and efficiently deliver hydrogen to consumers at prices competitive with gasoline and without adverse environmental impacts; and

• Transportation fuel cell power system costs of less than $50/kW (in high-volume production) while meeting performance and durability requirements.

DOE requested a study by the National Research Council (NRC) and the National Academy of Engineering (NAE) to assess the current state of technology for hydrogen production and use, and to review and provide feedback on the DOE RD&D hydrogen program, including recommendations for priorities and strategies to develop a hydrogen economy. The resulting report (NRC/NAE 2004) addressed implications for national goals, R&D priorities, and criteria for transition to a hydrogen economy. It provided recommendations in the areas of systems analysis, fuel cell vehicle technology, infrastructure, transition, safety, CO₂-free hydrogen, carbon capture and storage, and DOE's hydrogen RD&D program. In addition to research being conducted within DOE's Hydrogen, Fuel Cells and Infrastructure Program, the NRC report also addressed DOE's programs for hydrogen production from nuclear and fossil energy sources.

Current Portfolio

Hydrogen production from nuclear power RDD&D goals target high-temperature, high-efficiency fission to produce electricity to generate hydrogen from water. Major research areas include support for the development of high-temperature materials, separation membranes, advanced heat exchangers, and supporting systems relating to hydrogen production using the sulfur-iodine (S-I) thermochemical cycle and high-temperature electrolysis. Alternative processes having significantly more technical risk (because less is known about them) continue to be evaluated because their expected lower temperature requirements and, in some cases, reduced complexity could render them more economical in the longer term. 8

Figure 5-6 Possible Hydrogen Pathways (Source: U.S. Department of Energy Hydrogen Program) (Download PDF)

Near-term research program goals in this area include, by 2006: (1) completion of research of small-scale steam methane reformers with a projected cost of $3.00/kg hydrogen at the pump; and (2) development of alternative reactors, including auto-thermal reactors; and, by 2007, evaluation of whether renewable energy-when integrated with hydrogen production by water electrolysis-can achieve 64 percent net energy efficiency at a projected cost of $5.50/kg, delivered at 5,000 psi. Midterm goals call for demonstrating, by 2010, at the pilot-plant scale: (1) membrane separation and reactive membrane separation technology for hydrogen production from coal; and (2) distributed hydrogen production from natural gas with a projected cost of $2.50/kg hydrogen at the pump. Longer-term goals call for demonstrating, at laboratory-bench scale: (1) a photo-electrochemical water-splitting system; and (2) a biological system for water-splitting (or other substrates) that shows potential to achieve long-term costs that are competitive with conventional fuels. 9

The research program goals of hydrogen storage are: (1) by 2010, develop and verify hydrogen storage systems with 6 weight-percent, 1,500 watt-hrs/liter energy density, and at a cost of $4/kWh of stored energy; and (2) by 2015, develop associated technologies and verify hydrogen storage systems with 9 weight-percent, 2,700 watt-hrs/liter energy density, and at a cost of $2/kWh of stored energy. 10

Hydrogen Use. DOE aims to demonstrate high-efficiency, solid-oxide fuel cell/turbine hybrid-electric generation systems operating on gasified coal with carbon capture and storage, and to develop efficient and durable polymer electrolyte membrane (PEM) fuel cells appropriate for automotive and stationary applications. Additional research is underway to use hydrogen in auxiliary power units in heavy vehicles to supplant diesel engine power use for refrigeration and housekeeping tasks.

The research program goals in this area are: (1) by 2010, develop a 60 percent peak-efficient, durable, PEM fuel cell power system for transportation at a cost of $45/kW; and a distributed generation (50-250 kW) PEM fuel cell system operating on natural gas or propane that achieves 40 percent electrical efficiency and 40,000 hours durability at $400-750/kW; and (2) by 2015, reduce the cost of PEM fuel cell power systems to $30/kW for transportation systems. 11

The overall goal in this area is to validate, by 2015, integrated hydrogen and fuel cell technologies for transportation, infrastructure, and electric generation in a systems context under real-world operating conditions. Specific goals include the following: (1) by 2006, complete development of a laboratory-scale distributed natural-gas-to-hydrogen production and dispensing system that can produce 5,000 psi hydrogen for $3.00/gge; (2) by 2008, demonstrate stationary fuel cells with a durability of 20,000 hours and 32 percent efficiency; (3) by 2009, demonstrate vehicles with greater than 250-mile range and 2,000-hour fuel cell durability; and (4) by 2009, demonstrate hydrogen production at $3/gge. By 2015, the research program aims to provide critical statistical data that demonstrate that fuel cell vehicles can meet targets of 5,000-hour fuel cell durability, storage systems can efficiently meet 300+ mile range requirements, and hydrogen fuel costs between $2.00 and $3.00/gge. The technology-validation effort also provides information in support of technical codes and standards development of infrastructure safety procedures. 12

Figure 5-7 A systems approach is needed for integrated hydrogen production, delivery, and storage, as well as for refueling hydrogen vehicles. Courtesy: DOE/NREL, Credit: Warren Gretz

Future Research Directions

5.3 Renewable Energy and Fuels

Box 5-1 Renewable Energy and Fuels Technologies Wind Energy Solar Photovoltaic Power Solar Buildings Concentrating Solar Power Biochemical Conversion of Biomass Thermochemical Conversion of Biomass Biomass Residues Energy Crops Waste-to-Energy Photoconversion Advanced Hydropower Geothermal Energy

Renewable sources of energy include the energy of the sun, the kinetic energy of wind, the thermal energy inside the Earth itself, the kinetic energy of flowing water, and the chemical energy of biomass and waste. These sources of energy, available in one or more forms across the globe, can be converted and/or delivered to end users as electricity, heat, fuels, hydrogen, and useful chemicals and materials. Box 5-1 lists 12 renewable energy technologies, many of which are discussed in Technology Options for the Near and Long Term. In the United States in 2003, of the 71.42 quads of net energy supply and disposition (98.22 quads total energy consumption), renewable resources contributed 5.89 quads (8 percent of supply, or 6 percent of the total). Of the renewable energy, 2.78 quads came from hydropower, 2.72 quads from burning biomass (wood and waste), 0.28 quads from geothermal energy, and 0.12 quads from solar and wind energy combined. An additional 0.24 quads of ethanol were produced from corn for transportation (EIA 2005).

The technologies in the suite of renewable energy technologies are in various states of market penetration or readiness. In many cases, industry has the financial incentive to make incremental improvements to commercialized renewable energy technologies, or other policies exist to promote renewable energy development and deployment (research and experimentation tax credit, State renewable portfolio standards). These and other factors are important to consider as CCTP helps to prioritize Federal investments.

Hydropower is well established, but improvements in the technology could increase its efficiency and widen its applicability. Geothermal technologies are established in some areas and applications, but significant improvements are needed to tap broader resources. The installation of wind energy has been rapidly and steadily expanding during the past several years. In the past decade, the global wind energy capacity has increased tenfold-from 3.5 GW in 1994 to almost 59 GW by the end of 2006. Technology improvements will continue to lower the cost of land-based wind energy and will enable access to the immense wind resources in shallow and deep waters of U.S. coastal areas and the Great Lakes near large energy markets. The next generations of solar-with improved performance and lower cost-are in various stages of concept identification, laboratory research, engineering development, and process scale-up. Also, the development of integrated and advanced systems involving solar photovoltaics, concentrating solar power, and solar buildings are in early stages of development; but advances in these technologies are expected to make them competitive with conventional sources in the future.

Biochemical and thermochemical conversion technologies also range broadly in their stages of development, from some that need only to be proved at an industrial scale, to others that need more research, and to others in early stages of scientific exploration. In the general category of photo-conversion, most technical ideas are at the earliest stages of concept development, theoretical modeling, and laboratory experiment. Waste-to-energy accounts for more than 2.5 gigawatts of power production.

The energy-production potential and siting of the various types of renewable energy facilities is dependent on availability of the applicable natural resources. Figures 5-8 through 5-12 show global wind capacity growth and availability of key U.S. renewable resources as estimated by the National Renewable Energy Laboratory (NREL) at the Renewable Resource Data Center.

Potential Role of Technology

In addition, the diversity of renewable energy sources offers a broad array of technology choices that can reduce CO₂emissions. The generation of electricity from solar, wind, geothermal, or hydropower sources contributes no CO₂or other GHGs directly to the atmosphere. Increasing the contribution of renewables to the Nation's energy portfolio will directly lower GHG intensity (GHGs emitted per unit of economic activity) in proportion to the amount of carbon-emitting energy sources displaced.

Figure 5-8 Global Wind Capacity Growth (Source: BTM Consult Aps, March 2003; Windpower Monthly, January 2005; NREL estimate for 2005)

Analogous to crude oil, biomass can be converted to heat, electrical power, fuels, hydrogen, chemicals, and intermediates. Biomass refers to both biomass residues (agricultural wastes such as corn stover and rice hulls, forest residues, pulp and paper wastes, animal wastes, etc.) and to fast-growing "energy crops," chosen specifically for their efficiency in being converted to electricity, fuels, etc. The CO₂consumed when the biomass is grown essentially offsets the CO₂released during combustion or processing. Biomass systems actually represent a net sink for GHG emissions when biomass residues are used, because this avoids methane emissions that result from landfilling unused biomass (Figures 5-13 and 5-14). Biorefineries of the future could produce value-added chemicals and materials together with fuels and/or power from nonconventional, lower-cost feedstocks (such as agricultural and forest residues and specially grown crops) with no net CO₂emissions.

Figure 5-9 U.S. Biomass Resources (Source: DOE Office of Energy Efficiency and Renewable Energy)

Technology Strategy

Figure 5-10 U.S. Solar Resources (Source: DOE Office of Energy Efficiency and Renewable Energy)

Figure 5-11 U.S. Land-Based Wind Resources (Source: DOE Office of Energy Efficiency and Renewable Energy)

Figure 5-12 U.S. Geothermal Resources (Source: DOE Office of Energy Efficiency and Renewable Energy)

Figure 5-13 Bioenergy Cycle Courtesy: DOE/ORNL

Transitioning from today's reliance on fossil fuels to a global energy portfolio that includes significant renewable energy sources will require continued improvements in cost and performance of renewable technologies. This transition would also require shifts in the energy infrastructure to allow a more diverse mix of technologies to be delivered efficiently to consumers in forms they can readily use. For example, changes to the electricity infrastructure are needed to accommodate greatly increased use of renewable electric generation. These changes include additional transmission lines to access those renewable resources that are located far from load centers; grid operating practices and storage to accommodate renewables that are intermittent, such as wind and solar; greater use of renewables in a distributed generation mode; and adapting current fossil generation for biomass co-firing. Fortunately, there already is substantial progress in adapting the electricity infrastructure to enable greater use of renewables generation, and additional changes that would be needed are relatively easy to make in a decade or so. With regard to renewable fuels used for transportation, no significant changes to vehicles and refueling infrastructure are needed until E10 ethanol (90 percent gasoline, 10 percent ethanol) in gasoline blends captures 10 percent of gasoline markets. When 85 percent ethanol/gasoline blends (E85) expand, which is expected if ethanol costs come down further, limited refueling infrastructure modifications will be needed. However, refueling technology needed for E-85 is already well developed, and several automobile manufacturers are already selling E-85 vehicles at low or no incremental costs.

In general, as performance continues to improve and costs continue to decline, improved new generations of technologies will replace today's renewable technologies. Combinations of renewable and conventional technologies and systems-and, therefore, integration and interconnection issues-will grow in importance.

Figure 5-14 Biomass as Feedstock for a Bioenergy and Bioproducts Industry (Source: ORNL 2005)

The transition from today's energy mix to a state of GHG stabilization can be projected as an interweaving of individual renewable energy technologies with other energy technologies, as well as market developments through the upcoming decades. Today, grid-connected wind energy, geothermal, solar energy, and biopower systems are well established. Demand for these systems is growing in some parts of the world. Solar hot-water technologies are reasonably established, although improvements continue. Markets are growing for small, high-value or remote applications of solar photovoltaics; wind energy; biomass-based CHP; certain types of hydropower; and integrated systems that usually include natural gas or diesel generators. Other technologies and applications today are in various stages of research, development, and demonstration. Possible near-, mid-, and long-term pathways for renewable energy are discussed in the following paragraphs.

In the near term, as system costs continue to decrease, the penetration of off-grid systems could continue to increase rapidly, including integration of renewable systems such as photovoltaics into buildings. As interconnection issues are resolved, the number of grid-connected renewable systems could increase quite rapidly, meeting local energy needs such as uninterruptible power, community power, or peak shaving. Wind energy may expand most rapidly among grid-connected applications, with solar expanding as system costs are reduced. Environment-friendly hydropower systems could be further developed. The use of utility-scale wind technology is likely to continue to expand onshore and is targeted to become competitive in select offshore locations between 5 and 50 nautical miles from shore and at water depths of 30 meters or less. Small wind turbines are on the verge of operating cost-effectively in most of the rural areas of the United States, and more than 15 million homes have the potential to generate electricity with small wind turbines. 14 With a further maturing of the market, costs will be lowered to compete directly with retail rates for homeowners, farmers, small businesses, and community-based projects.

The biomass near-term outlook includes industry investment to make the production of corn-based ethanol (already produced at nearly 4 billion gallons) more efficient by increasing the quantity of ethanol through residual starch conversion, and conversion of fiber already collected and present at the operating facilities. The inclusion of biochemicals as byproducts will further help to improve the industry's profitability. The Biofuels Initiative launched in FY 2007 will accelerate demonstrations of biorefinery concepts, producing one or more products (bioethanol, bioproducts, electricity, CHP, etc.) from one plant using local waste and residues as the feedstock. Biodiesel use may continue to grow, replacing fossil-fuel-derived diesel fuel. The technology being developed to convert agricultural residues to ethanol is also partially applicable to the conversion of municipal solid waste to ethanol.

A recent assessment of potential biofuel resources concluded that by mid-21st century it would be technically possible to produce enough biomass to displace about one-third of current petroleum consumption. The study made no conclusions about economic feasibility. This level of biofuel production would require economically-competitive technologies to convert cellulosic biomass (rather than just the sugars and starches) into ethanol, and developing cellulosic ethanol technologies is a central aspect of the Biofuels Initiative and the President's Advanced Energy Initiative.

In the mid term, offshore wind energy could begin to expand significantly. Technology development may focus on turbine-support structures suitable for deeper water depths, and reducing turbine system and balance-of-plant costs to offset increased distance from shore, decreased accessibility, and more stringent environmental conditions. Land-based use of wind turbines is also likely to expand for large and small turbines as the costs for these systems continue to decrease. Small turbines may be used to harness wind to provide pumping for farm irrigation, help alleviate water-availability problems, and provide a viable source of clean and renewable hydrogen production. 15

Reductions in cost could encourage penetration by solar technologies into large-scale markets, first in distributed markets such as commercial buildings and communities, and later in utility-scale systems. Solar systems could also become cost-effective in new construction for commercial buildings and homes. The first geothermal plants using engineered geothermal systems technology could come online, greatly extending access to geothermal resources. Hydropower may benefit from full acceptance of new turbines and operational improvements that enhance environmental performance, lowering barriers to new development.

As a result of the Biofuels Initiative, biorefineries could begin using agricultural and forest residues, and eventually energy crops as primary feedstocks. Assuming success in reducing production costs and expanding the fuels distribution infrastructure, bioethanol and, to a lesser extent, biodiesel could achieve substantial market penetration in the 2030-2040 timeframe. This would be an important step in lowering U.S. dependence on imported petroleum.

In the long term, hydrogen from solar, wind, and possibly geothermal energy could be the backbone of the economy, powering vehicles and stationary fuel cells. Solar technologies could also be providing electricity and heat for residential and commercial buildings, industrial plants, and entire communities in major sections of the country. A major value for solar is that most residential and commercial buildings could generate their own energy on-site. Wind energy could be the lowest-cost option for electricity generation in favorable wind areas for grid power, and offshore systems could become prevalent in many countries by achieving a commercially viable cost by using floating platform technologies. Geothermal systems could be a major source of baseload electricity for large regions. Biorefineries could be providing a wide range of cost-effective products as rural areas embrace the economic advantages of widespread demand for energy crops. Vehicle fuels could be powered by a combination of hydrogen fuel cells, with some bioethanol and biodiesel in significant markets.

Current Portfolio

Research program goals in this area vary by application. For distributed wind turbines under 100 kW, the goal is to achieve a power production cost of $0.10 to 0.15/kWh in Class 3 winds by 2007. For larger systems greater than 100 kW, the goal is to achieve a power production cost of $0.036/kWh for land-based at sites with average wind speeds of 13 mph (wind Class 4) by 2012, and $0.05/kWh at shallow (depths up to 30 meters) offshore sites with average wind speeds of 15 mph (wind Class 6) by 2014, and $0.05/kWh for transitional (depths up to 60 meters) offshore systems in Class 6 winds by 2016. 16

Research program goals in this area focus primarily on a new initiative-the Solar America Initiative (SAI)-which will accelerate R&D efforts designed to achieve market competitiveness for PV solar electricity by 2015 (i.e., 5 to 10 cents/kWh under ideal siting and financing conditions). The accelerated R&D effort will focus on PV technology pathways that have the greatest potential to lower costs and improve performance. New industry-led R&D partnerships, known as "Technology Pathway Partnerships," will be funded to address the issues of cost, performance, and reliability associated with each technology pathway. Potential partners within the Technology Pathway Partnerships include industry, universities, laboratories, States, and other governmental entities. If the research is successful and if other policies remain in place to promote deployment (production tax credits, State renewable portfolio standards), then by 2015, 5-10 GW of new solar power capacity could be deployed, equivalent to the amount of electricity needed to power 1-2 million homes. This deployment level would result in 10 million metric tons of avoided carbon dioxide emissions in the United States. The interim cost goal is to reduce the 30-year user cost for PV electrical energy to a range of $0.11 to 0.18/kWh under ideal conditions by 2010. 17

Figure 5-15 Research and development activities on solar photovoltaic power, conducted at Federal laboratories and the private sector, help to improve efficiencies, lower production costs, and resolve technical issues. Courtesy: DOE/NREL, Credit: United Solar Systems Corp.

By FY 2007, the goal is to complete a preliminary engineering design package, market analysis, and financial projections for two industrial-scale projects for near-term agricultural pathways (corn wet mill, corn dry mill, oilseed) to produce a minimum of five million gallons of biofuels per year. The intent is to provide proof that the resultant industrial-scale biorefineries could produce and market biofuels at prices competitive with petroleum fuels produced from $50-per-barrel oil. By 2009, develop a conceptual, novel harvesting system and test a wet storage system for agricultural residues. By 2012, the goal is to reduce the estimated cost for producing a mixed, dilute sugar stream suitable for fermentation to ethanol, to $0.096/lb, compared to the cost of $0.15/lb in 2003. If successful, this cost goal would correspond to $1.50 per gallon of ethanol, assuming a cost of $45 per dry ton of corn stover. 20

The mid- to long-term research program goal in this area is to reduce biomass harvesting and storage costs so that the delivered cost will be reduced from $53 per dry ton in 2003 to $45 per dry ton by 2012. The Biofuels Initiative of 2007 proposes to establish three regional biomass development partnerships in conjunction with land grant universities to develop research-specific data on feedstock availability, productivity, markets, and economics by 2008, and an additional partnership by 2009. Engineering designs and techno-economic assessments of integrated wet biomass storage and field preprocessing will be completed by 2008. By 2010, engineering design on multi-crop feedstock depot systems that can receive a variety of feedstocks and preprocess will then be completed. 22

The overall research goal of this program is to advance the concept of energy crops contributing strongly to meet biomass power and biofuels production goals by 2020. Interim goals include: (1) by 2006, to develop feedstock crops with experimentally demonstrated yield potential of 6-8 dr y ton/acre/year and accompanying cost-effective, energy-efficient, environmentally sound harvest methods; (2) by 2010, the goal is to identify genes that control growth and characteristics important to conversion processes in few model energy crops and achieve low-cost, "no-touch" harvest/ processing/transport of biomass to the process facility; and (3) by 2020, the goal is to increase yield of useful biomass per acre by a factor of 2 or more compared with year 2000 yields. 23

The research program in this area is still in an exploratory stage. In the near term, research will focus on applications related to electrical power and high-value fuels and chemicals, where commercial potential may be expected during the next 5 to 10 years. If successful, larger-scale applications of photoconversion technologies may follow in the period from 2010 to 2015, with materials and fuels production beginning in the period 2015 to 2020, and commodity chemicals production in the period from 2020 to 2030. 24

Future Research Directions

Figure 5-16 The Department of Energy is working closely with industry to research and develop new, advanced wind turbine technology. Courtesy: GE Energy, ©2005, General Electric International, Inc.

5.4 Nuclear Fission

During the past 30 years, operators of U.S. nuclear power plants have steadily improved economic performance through reduced costs for maintenance and operations and improved power plant availability, while operating reliably and safely. In addition, science and technology for the safe storage and ultimate disposal of nuclear waste have been advanced. Waste from nuclear energy must be isolated from the environment. High-level nuclear wastes from fission reactors (used fuel assemblies) are stored in contained, reinforced concrete steel-lined pools or in robust dry casks at limited-access reactor sites, until a deep geologic repository is ready to accept and isolate the spent fuel from the environment. Used nuclear fuel contains a substantial quantity of fissionable materials, and advanced technologies may be able to recover energy from this spent fuel and reduce required repository space and the radiotoxicity of the disposed waste.

Figure 5-17 More than 400 successfully operating civilian nuclear power plants around the world avoid billions of tons of CO₂emissions for the atmosphere. Credit: ©Royalty-Free/CREATAS

While the current application of nuclear energy is the production of electricity, other applications are possible, such as cogeneration of process heat, the generation of hydrogen from water or from methane (with carbon capture or integration with other materials production or manufacturing), and desalination.

Potential Role of Technology

To the extent that the financial risks of new nuclear construction can be addressed and with improvement from new technologies in the longer term, the nuclear option can continue to be an important, growing part of a GHG-emissions-free energy portfolio. Design and demonstration efforts on near-term advanced reactor concepts-in combination with Federal financial risk mitigation tools-will enable power companies to build and operate new reactors that are economical and competitive with other generation technologies, supporting energy security and diversity of supply.

Figure 5-18 Nuclear Reactors Under Active Construction Worldwide (Source: World Nuclear Association26)

Evolutionary light-water reactors of standardized design (having received U.S. Nuclear Regulatory Commission design certification and having been constructed on schedule in Japan and South Korea) are demonstrated and available now for construction in the United States. Other newer designs should be reviewed and certified over the next several years, making them also available. However, more advanced nuclear energy systems for the longer term have the potential to offer significant advances in the areas of sustainability, proliferation resistance and physical protection, safety, and economics. These advanced nuclear energy systems-described as Generation IV reactors-could replace or add to existing light-water reactor capacity.

Technology Strategy

In the longer term, advanced nuclear energy systems could serve a vital role in both diversifying the Nation's energy supply and reducing GHG emissions. By successfully addressing the fundamental research and development issues of system concepts that excel in safety, sustainability, cost-effectiveness, and proliferation resistance, the systems could attract future private-sector sponsorship and ultimate commercialization by the private sector. Advanced nuclear fission-reactor systems aim to extract the full energy potential of the spent nuclear fuel from current fission reactors, while reducing or eliminating the potential for proliferation of nuclear materials and technologies, and reducing both the radiotoxicity and total amount of waste produced.

A key objective of nuclear energy research and development is to enhance the basic technology and, through advanced civilian technology research, chart the way toward the next leap in technology. From these efforts, and those of industry and overseas partners, nuclear energy may continue to fulfill its promise as a safe, advanced, inexpensive, and emission-free approach to providing reliable energy throughout the world.

Current Portfolio

A Roadmap to Deploy New Nuclear Power Plants in the United States by 2010, issued in October 2001 (DOE 2001), advises DOE on actions and resource requirements needed to put the country on a path to bringing new nuclear power plants on-line in the next decade. The primary purposes of the roadmap are to identify the generic and design-specific prerequisites to near-term deployment, to identify those designs that best promise to meet the needs of the marketplace, and to propose recommended actions that would support deployment. These include, but are not limited to, actions to achieve economic competitiveness and timely regulatory approvals.

The Nuclear Power 2010 Program is a joint government/industry cost-shared effort. The program is designed to pave the way for an industry decision to order at least one new nuclear power plant by the end of the decade. Activities under this program support cost-shared demonstration of the Early Site Permit (ESP) and combined Construction and Operating License (COL) processes to reduce licensing uncertainties and minimize the attendant financial risks to the licensee. In addition, the program includes technology research and development to finalize and license a standardized advanced reactor design, which U.S. power-generation companies will find to be more competitive in the deregulated electricity market. The economics and business case for building new nuclear power plants has been evaluated as part of the Nuclear Power 2010 program to identify the necessary financial conditions under which power-generation companies would add new nuclear capacity.

The research program goals in this area are focused on successfully demonstrating the untested regulatory processes for ESP and combined COL, and on the regulatory acceptance (certification) and completion of first-of-a-kind engineering and design. Specific goals include industry decisions to build new nuclear power plants by 2009 with commercial operation in the next decade.27

Development of next-generation nuclear energy systems is being pursued by the Generation IV International Forum (GIF) [www.gen-4.org], a group of 10 leading nuclear nations (Argentina, Brazil, Canada, France, Japan, the Republic of Korea, the Republic of South Africa, Switzerland, the United Kingdom, and the United States) plus the European Atomic Energy Community (Euratom). The GIF has selected six promising technologies as candidates for advanced nuclear energy systems concepts. The Gen IV addresses the fundamental research and development issues necessary to establish the viability of next-generation nuclear energy system concepts. After successfully addressing the viability issues, the systems are highly likely to attract future private-sector sponsorship and ultimate commercialization by the private sector.

The primary focus of these Gen IV systems will be to generate electricity in a safe, economical, and secure manner; other possible benefits include the production of hydrogen, desalinated water, and process heat (Figure 5-19). In particular, making nuclear power sustainable over the long term requires developing and deploying proliferation-resistant fuel recycling technology and fast reactors for breeding new fuel and transmuting higher actinides. The GIF and DOE's Nuclear Energy Research Advisory Committee (NERAC) issued a report on its two-year effort to develop a technology roadmap for future nuclear energy systems (GIF-NERAC 2002). The technology roadmap defines and plans the necessary R&D to support the advanced nuclear energy systems known as Gen IV. DOE also prepared a report to the U.S. Congress regarding how it intends to carry out the results of the Gen IV Roadmap (DOE-NE 2003a).

Goals for next-generation fission energy systems (Gen IV) research are focused on the design of reactors and fuel cycles that are safer, more economically competitive, more resistant to proliferation, produce less waste, and make better use of the energy content in uranium, in accord with the above-mentioned reports and roadmaps.28

Figure 5-19 Future Nuclear Power Concepts (Source: DOE, Office of Nuclear Energy Internal Document).

The AFCI program will develop technologies to address intermediate and long-term issues associated with spent nuclear fuel. The intermediate-term issues are the reduction of the volume and heat generation of material requiring geologic disposal. The program will develop proliferation-resistant processes and fuels for application to current light-water reactor systems and Gen IV reactor systems to enable the energy value of these materials to be recovered, while destroying significant quantities of plutonium. This work provides the opportunity to optimize use of the Nation's first repository and reduce the technical need for an additional repository. The longer-term issues to be addressed by the AFCI program are the development of fuel-cycle technologies to destroy minor actinides, which would greatly reduce the long-term radiotoxicity and heat load of high-level waste sent to a geologic repository. This will be accomplished through the development of Gen IV fast reactor fuel-cycle technologies and possibly of accelerator-driven systems (DOE-NE 2003b).

Goals for advanced nuclear fuel-cycle research focus on proving design principles of spent-fuel treatment and transmutation technologies, demonstrating the fuel and separation technologies for waste transmutation, and deploying Gen IV advanced fast spectrum reactors that can transmute nuclear waste.29

Future Research Directions

5.5 Fusion Energy

Fusion power generation offers a number of advantageous features. The basic sources of fusion fuel, deuterium and tritium, are actually heavy forms of hydrogen. Deuterium is abundantly available because it occurs naturally in water; and tritium can be derived from lithium, a light metal found in the earth's crust. Tritium is radioactive, but the quantities in use at any given time are quite modest and can be safely handled. There are no chemical pollutants or CO₂emissions from the fusion process. With appropriate advances in materials, the radioactivity of the fusion byproducts would be relatively short-lived, thereby obviating the need for extensive waste management measures.

From a safety perspective, the fusion process poses little radiation risk to anyone outside the facility. Also, since only a small quantity of fuel is in the fusion system at any given time, there is no risk of a critical accident or meltdown, and little after-heat to be managed in the event of an accident. The potential usefulness of fusion systems is great, but significant scientific and technical challenges remain.

Potential Role of Technology

Energy scenarios imposing reasonable constraints on nonsustainable energy sources show that fusion energy could contribute significantly to large-scale electricity production during the second half of the 21st century.

Making fusion energy a part of the future energy solution is among the most ambitious scientific and engineering challenges of our era. The following are some of the major technical questions that need to be answered:

Answering these questions requires understanding and control of complex and dynamic phenomena occurring across a broad range of temporal and spatial scales. The experiments required for a commercially viable fusion power technology constitute a complex scientific and engineering enterprise.

Technology Strategy

Fusion Energy Sciences Goal #1:

Fusion Energy Sciences Goal #2:

Fusion Energy Sciences Goal #3:

Fusion Energy Sciences Goal #4:

Current Portfolio

The overall effort requires operation of a set of unique and diversified experimental facilities, ranging from smaller-scale university programs to several large national facilities that require extensive collaboration. These facilities provide scientists with the means to test and extend theoretical understanding and computer models, leading ultimately to an improved predictive capability for fusion science.

The two major tokamak experiments, DIII-D at General Atomics and the Alcator C-Mod at MIT, are extensively equipped with sophisticated diagnostics that allow for very detailed measurements in time and spatial dimensions as they continuously push the frontiers of tokamak plasma confinement. They each involve an array of national and international collaborators on the scientific programs.

Similarly, the NSTX at PPPL is also a well-diagnosed and highly collaborative experiment on an innovative confinement approach that seems likely to lead to improved understanding of toroidal31 confinement systems.

Figure 5-20 Fusion energy affords the possibility of long-term, sustainable energy supply, with little or no emissions of GHGs. Credit: National Compact Stellarator Experiment, DOE/PPPL

An additional innovative concept, the National Compact Stellarator Experiment, is currently being fabricated at PPPL with first operation scheduled for 2009 (Figure 5-20). This machine is a product of new computational capabilities that have optimized the 3-dimensional toroidal magnetic geometry for improved confinement and stability in a compact form.

In addition to these major experiments, there are a larger number of smaller magnetic confinement experiments with more specialized missions. These are generally located at universities and provide an opportunity for student training.

A modest-scale high-energy-density physics program is also underway, with an emphasis on using heavy ion drivers to explore plasma/beam dynamics and warm dense matter with potential applications to future inertial fusion systems. This program also explores innovative approaches to improving inertial fusion such as the fast-ignition experiments. In addition, the FES program benefits from existing experimental programs conducted elsewhere for NNSA's stockpile stewardship program and the Department of Defense (DoD). Both the "Z" experiment at Sandia National Laboratories and the OMEGA experiment at the University of Rochester, for example, offer opportunities for improving understanding of high-energy-density physics.

Figure 5-21 The United States is participating with other countries in the building of ITER, a large-scale fusion process machine, which will provide experimental data to inform future technology directions. Credit: ITER

Theory and computing are key parts of the present program, as they provide the intellectual framework for the overall approach to fusion energy, as well as the computer codes, which attempt to systematically rationalize the understanding of fusion plasmas. [34]

Future Research Directions

5.6 Summary

As one illustration among the many hypothesized cases analyzed,36 when GHG emissions were constrained to a high level over the course of the 21st century the lowest-cost arrays of advanced technology in energy supply, when compared to a reference case, resulted in reduced or avoided emissions of roughly between 110 and 210 GtC. This amounted to, roughly, between 20 and 35 percent of all GHG emissions reduced, avoided, captured and stored, or otherwise withdrawn and sequestered, needed to constrain emissions at this level. Similarly, the costs for achieving such emissions reductions, when compared to the reference case, were reduced by roughly a factor of 3. See Chapter 3 for other cases and other scenarios.

As described in this chapter, CCTP's technology development strategy supports achievements in this range. The overall strategy is summarized schematically in Figure 5-22. Advanced technologies are seen entering the marketplace in the near, mid, and long terms, where the long term is sustained indefinitely. Such a progression, if successfully realized worldwide, would be consistent with attaining the energy supply potential portrayed at the beginning of this chapter.

The timing and pace of technology adoption are uncertain and must be guided by science. In the case of the illustration above, the first GtC per year (1GtC/year) of reduced or avoided emissions, as compared to an unconstrained reference case, would need to be in place and operating between 2040 and 2060. For this to happen, a number of new or advanced energy supply technologies would need to penetrate the market at significant scale before this date. Other cases would suggest faster or slower rates of deployment, depending on assumptions. See Chapter 3 for other cases and other scenarios.

Figure 5-22 Technologies for Goal #2: Reducing Emissions from Energy Supply (Note: Technologies shown are representations of larger suites. With some overlap, "near-term" envisions significant technology adoption by 10 to 20 years from present, "mid-term" in a following period of 20-40 years, and "long-term" in a following period of 40-60 years. See also List of Acronyms and Abbreviations.) (Download PDF)

References

Generation IV International Forum (GIF) and the U.S. Department of Energy's Nuclear Energy Research Advisory Committee (NERAC). 2002. A Technology Roadmap for Generation IV Nuclear Energy Systems. GIF-002-01, December.

International Energy Agency (IEA). 2004. Key World Energy Statistics 2004.

National Research Council (NRC), National Academy of Engineering (NAE). 2004. The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs. Washington, DC: The National Academies Press.

Oak Ridge National Laboratory (ORNL). 2005. Biomass as Feedstock for a Biorefinery and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Supply.

U.S. Climate Change Technology Program (CCTP). 2003. Technology Options for the Near and Long Term. DOE/PI-0002. Washington, DC: U.S. Department of Energy.

Update is at US Climate Change Technology Program.

U.S. Department of Energy (DOE). 2005. Hydrogen Fuel Cells and infrastructure Technologies Multi-Year Research, Development and Demonstration Plan, 2003-2010. Washington, DC: U.S. Department of Energy.

U.S. Department of Energy (DOE). 2004. Hydrogen Posture Plan, an Integrated Research, Development, and Demonstration Plan. Washington, DC: U.S. Department of Energy.

U.S. Department of Energy (DOE), Office of Nuclear Energy Science and Technology (NE). 2001. A Roadmap to Deploy New Nuclear Power Plants in the United States by 2010. Washington, DC: U.S. Department of Energy.

U.S. Department of Energy, (DOE), Office of Nuclear Energy Science and Technology (NE). 2003a. The U.S. Generation IV Implementation Strategy. Washington, DC: U.S. Department of Energy.

U.S. Department of Energy, (DOE), Office of Nuclear Energy Science and Technology (NE). 2003b. Report to Congress on Advanced Fuel Cycle Initiative: the Future Path for Advanced Spent Fuel Treatment and Transmutation Research. Washington, DC: U.S. Department of Energy. [TEMP BROKEN]

Footnotes

2 The report is available at U.S. Climate Change Technology Program

3 Avoided carbon emissions were calculated based on current coal consumption and power plant efficiencies from the Energy Information Administration's Annual Energy Outlook 2002. Using the published efficiencies, 0.574 quads of energy were saved with a 1 percent improved efficiency, which would result in 14.8 MMT of carbon avoided.

4 Visit site for more information.

5 See Section 2.1.2 (CCTP 2005):

6 See Section 2.1.3 (CCTP 2005).

7 See Section 2.1.1 (CCTP 2005).

8 See Section 2.2.1 (CCTP 2005).

9 See Section 2.2.3 (CCTP 2005).

10 See Section 2.2.4 (CCTP 2005).

11 See Section 2.2.5 (CCTP 2005).

12 See Section 2.2.2 (CCTP 2005).

13 See Section 2.2.6 (CCTP 2005).

14 U.S. Small Wind Turbine Industry Roadmap, NREL Report No. BK-500-31958; DOE/GO-102002-1598, 2002 .

15 National Academy of Science, The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs .

16 See Section 2.3.1 (CCTP 2005).

17 See Section 2.3.2 (CCTP 2005).

18 See Section 2.3.3 (CCTP 2005).

19 See Section 2.3.4 (CCTP 2005).

20 See Section 2.3.5 (CCTP 2005).

21 See Section 2.3.6 (CCTP 2005).

22 See Section 2.3.7 (CCTP 2005).

23 See Section 2.3.8 (CCTP 2005).

24 See Section 2.3.9 (CCTP 2005).

25 See Section 2.3.11 (CCTP 2005).

26 Visit site for more information. [TEMP BROKEN]

27 See Section 2.4.2 (CCTP 2005).

28 See Section 2.4.1 (CCTP 2005).

29 See Section 2.4.3 (CCTP 2005).

30 Tokamak (Acronym created from the Russian words, "TOroidalnaya KAmera ee MAgnitnaya Katushka," or "Toroidal Chamber and Magnetic Coil"): The tokamak is the most common research machine for magnetic confinement fusion today.

31 Toroidal: in the shape of a torus, or doughnut. Toroidal is a general term that refers to toruses as opposed to other geometries (e.g., tokamaks and stellarators are examples of toroidal devices).

32 See Section 2.5.1 (CCTP 2005).

33 For additional information about ITER.

34 Inertial fusion is an alternative approach to creating the physical conditions necessary for light elements to fuse and release binding energy, in which an array of intense x-rays, lasers, or heavy ion beams are used to contain, compress, and heat the fusible materials to fusion enabling conditions.

35 For additional information about U.S. fusion energy research.

36 In Chapter 3, various advanced technology scenarios were analyzed for cases where global emissions of GHGs were hypothetically constrained. Over the course of the 21st century, growth in emissions was assumed to slow, then stop, and eventually reverse in order to ultimately stabilize GHG concentrations in the Earth's atmosphere at levels ranging from 450 to 750 ppm. In each case, technologies competed within the emissions-constrained market, and the results were compared in terms of energy (or other metric), emissions, and costs.