The Energy Challenge
Mission Science Goals: Understand the principles underlying the structural and functional design of living systems, and develop the capability to model, predict, and engineer optimized enzymes and microorganisms for the production of such biofuels as ethanol and hydrogen.
Challenges: Analyze thousands of natural and modified variants of such processes as cellulose degradation, fermentative production of ethanol or other liquid fuels, and biophotolytic hydrogen production.
Meeting projected increases in energy demand while decreasing dependence on foreign sources of energy defines America’s energy challenge. From 2003 to 2025, U.S. energy demand is projected to increase by 35%, much greater than the projected increase in domestic production (Annual Energy 2005). Making up this projected shortfall without increasing imports will require investments in science and technologies that will improve conservation and efficiency and expand the domestic energy supply system. A primary goal of the national energy policy is not only to increase domestic supply but also to broaden our range of options in ways that will reduce vulnerabilities to supply disruptions and protect the environment (Reliable 2001).
Another key factor in America’s energy challenge is rising carbon dioxide (CO2) emissions. CO2 is the most abundant greenhouse gas (GHG) in the atmosphere, and, based on projected energy use between 2003 and 2025, U.S. CO2 emissions could increase almost 40% (Annual Energy 2005). With accelerated growth in fossil-fuel consumption projected for developing regions of the world, by 2025 annual global CO2 emissions could be 55% higher than in 2001 (International Energy 2004). In 2002, global energy use emitted about 7 gigatons of CO2 into the atmosphere. Several long-term projections estimated that CO2 emissions could be as high as 30 GtC/year by 2100 (Nakicenovic et al. 2000). Stabilizing the concentration of CO2 at any level requires that global CO2 emissions must peak eventually and begin a long-term decline, ultimately falling to virtually zero.
A variety of breakthrough energy technologies will be needed to significantly reduce CO2 emissions. To illustrate the scale of the CO2 emissions challenge, How Big is a Gigaton? provides examples of the types of technological actions required to reduce emissions by 1 GtC per year (Pacala and Socolow 2004).
Strategies for understanding the impacts of energy use on climate change and for developing technologies that will ensure economic prosperity while reducing GHG emissions are provided under the guidance of several government agencies through the Global Change Research Program (formerly Climate Change Science Program) and the Climate Change Technology Program (CCTP).
The Role of Biology and Biotechnology in America’s Energy Future
Biology played a key role in producing the fossil fuels so critical to meeting today’s world energy demand. Fossil fuels were once living biomaterials synthesized eons ago by photosynthetic and biochemical processes. A series of fortuitous geological events trapped these materials beneath the sediments of ancient seas, and, over millions of years, the right mix of heat, pressure, and other factors transformed the biomaterials into fossil fuels.
With biotechnological innovations, biology once again can play an important role in producing high-energy fuels. Plants and photosynthetic microorganisms are masters at harvesting chemical energy from sunlight—a virtually inexhaustible supply of energy. By harnessing their photosynthetic and other biochemical capabilities, biological systems can be used to satisfy a greater portion of energy demand.
Applying biology to build a new U.S. bioenergy industry can benefit this nation’s energy security, economy, and environment in many different ways. Biofuels, especially ethanol from plant materials (biomass), have the potential to reduce our dependency on foreign oil in the transportation sector and diversify our energy-technology portfolio. As renewable alternatives that can be harvested on a recurring basis, bioenergy crops (e.g., poplar trees and switchgrass) and agricultural residues (e.g., corn stover and wheat straw) can provide American farmers with important new sources of revenue. Consumption of biofuels produces no net CO2 emissions, releases no sulfur, and has much lower particulate and toxic emissions than fossil fuels (Greene et al. 2004). In addition to ethanol, other biobased energy alternatives include biodiesel, methanol, hydrogen, and methane (see sidebar, Biological Energy Alternatives).
Biomass currently is used to meet only 3% of U.S. energy consumption (Annual Energy 2005). In 2004, the United States produced 4 billion gallons of ethanol from corn grain, enough to meet about 2% of U.S. gasoline consumption (Homegrown 2005; Mann 2004). Ethanol from biomass has promise for meeting a significantly larger portion of U.S. gasoline demand, but higher production costs, technical difficulties, and inefficiencies in biomass conversion currently prevent ethanol from being cost-competitive with gasoline.
Another concern has been the uncertainty in determining how much land must be dedicated to growing bioenergy crops to make a real difference in oil demand and how this would impact current agricultural and forestry practices. A recent report prepared for the U.S. Department of Agriculture and Department of Energy (DOE) has projected that relatively modest changes in the use of farmlands and forests could produce more than 1.3 billion dry tons of biomass per year, enough to reduce current oil demand by about one-third (Biomass as Feedstock 2005). As research improves efficiencies in both agricultural production and biomass conversion, land and sunlight availability in the United States should be sufficient to produce enough biofuels to meet domestic transportation-related demand without disrupting agricultural land use for food and fiber crops.
In addition to reducing our dependence on oil, biofuels also have great potential for decreasing greenhouse gas emissions associated with fossil-fuel consumption. Figure 1. Potential Role of Biotechnology in the Global Energy System presents the results of an economic analysis exploring conditions under which markets for commercial biofuels could develop (Edmonds et al. 2003). In this figure, two potential scenarios for global energy consumption in the 21st Century are compared: A reference case in which innovations in energy technology take place without constraints on CO2 emissions and a CO2-stabilization case in which emissions are limited. In the stabilization case, biomass becomes a major component of the energy-technology portfolio, and by 2100 biomass usage is greater than that of all current fossil fuels (oil, natural gas, and coal) combined. A transition to such large-scale use of biofuels and biotechnologies could create a new bioenergy industry potentially worth trillions of dollars over the 21st Century.
Before biomass and biotechnologies can compete successfully with established energy sources for market share, basic research is needed for a more complete understanding of the biological processes underlying biofuel production. Applying this understanding in innovative ways will enable the development of breakthrough technologies. Since it can take 30 to 50 years for an energy technology to go from research to large-scale commercial deployment, this basic research is needed today.
GTL’s Vision for Biological Energy Alternatives
GTL will provide a systems-level understanding of biological processes for developing and deploying larges-scale, environmentally sound biotechnologies to produce biofuels and other high-value chemical products that reduce dependence on foreign energy sources and enhance national economic prosperity.
A national vision for bioenergy and biobased products was defined by the Biomass R&D Technical Advisory Committee (BTAC): “By 2030, a well-established, economically viable bioenergy and biobased products industry will create new economic opportunities for rural America, protect and enhance our environment, strengthen U.S. energy independence, provide economic security, and deliver improved products to consumers” (Vision for Bioenergy 2002). BTAC, established as a result of the Biomass Research and Development Act, is responsible for advising the Secretary of Agriculture and the Secretary of Energy on issues relevant to biomass research and development. BTAC also coordinates partnerships among government agencies, industry, researchers, and other groups with interests in biomass R&D (U.S. Congress 2000).
GTL supports this national vision by providing a detailed understanding of the microbial processes that mediate the production of biofuels. Our limited understanding of many of these processes presents fundamental scientific challenges that must be overcome before we can develop and deploy successful bioenergy technologies. In addition to advancing biofuel production, the capabilities and understanding of microbial systems provided by GTL will be applicable to the biotechnological development of other commercial chemical processes. Techniques used to design microbial systems for biofuel production could be used to develop other microbial systems optimized to convert biomass to biodegradable plastics and other chemical products currently derived from fossil fuels. Insights from GTL research could benefit several research areas supported by DOE’s Office of Energy Efficency and Renewable Energy (EERE).
Text adapted from Genomics:GTL Roadmap: Systems Biology for Energy and Environment, U.S. Department of Energy Office of Science, August 2005. DOE/SC-0090.
