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Executive Summary Safe, secure, clean, and affordable energy and transportation are essential to the social and economic vitality of the world. As we look to the future the next 50 years and beyond there will be many severe challenges for the energy and transportation systems of the world that must be met. The drivers will be created by population growth, economic growth, ever tightening environmental con- straints, increasing climate change issues and pressure for limits on carbon dioxide emissions, geopolitical impacts on energy availability and the energy market- place, a changing energy resource base, and a need for low emissions transporta- tion. Science and technology specifically chemistry and chemical engineering- will play critical, unique, and exciting roles in enabling the world to meet these challenges. As the second of six workshops held by the National Research Council for the study Challenges for the Chemical Sciences in the 21st Century, the Work- shop on Energy and Transportation sought to identify these key opportunities and challenges for the chemical sciences in the energy and transportation sectors. The workshop featured 12 keynote speakers who addressed the wide spectrum of challenges facing the chemical sciences in energy and transportation. Approxi- mately 100 chemists and chemical engineers from across the industrial, academic, and government research communities attended the workshop (participants are listed in Appendix E). The participants identified key challenges through a series of breakout sessions. The speakers and their presentation titles are listed below. Patricia A. Baisden Lawrence Livermore National Laboratory, "A Renaissance for Nuclear Power? 1

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2 ENERGY AND TRANSPORTATION Thomas R. Baker Los Alamos National Laboratory, "Opportunities for Catalysis Research in Energy and Jiri Janata James R. Katzer Transportation" Alexis T. Bell University of California, Berkeley, "Research Opportunities and Challenges in the Energy Sector" Georgia Institute of Technology, "Role of 21St Century Chemistry in Transportation and Energy" ExxonMobil, "Interface Challenges and Opportunities in Energy and Transportation" Nathan S. Lewis California Institute of Technology, "R&D Challenges in the Chemical Sciences to Enable Widespread Utilization of Renewable Energy Ralph P. Overend National Renewable Energy Laboratory, "Challenges for the Chemical Sciences in the 21st Century" Stephen W. Pacala Princeton University, "Could Carbon Sequestration Solve the Problem of Global Warming?" Venki Raman Air Products and Chemicals, "The Hydrogen Fuel Infrastructure for Fuel Cell Vehicles" Kathleen C. Taylor General Motors Corporation, and Anil Sachdev "Materials Technologies for Future Vehicles" John R. Wallace Ford Motor Company, "Fuel Cell Development Managing the Interfaces" Henry S. White University of Utah, "Nano- and Microscale Approaches to Energy Storage and Corrosion" Summaries of these presentations are presented in the main body of the report. A full agenda for the workshop may be found in Appendix D. The orga- nizing committee integrated the input from the presentations and breakout sessions to develop this report. In order to define the energy and transportation challenges and opportunities for the chemical sciences in the 21st century, the future needs can be divided into two time frames midterm (through 2025) and long term (2050 and beyond).) While these scenarios can be debated, the drives they create in the chemical sci- ences are not greatly affected by the severity of the scenarios. They do point to a iThese future needs were identified by the committee based on the Workshop presentations. For each need, the presentation from which it was identified is given in parentheses.

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EXECUTIVE SUMMARY 3 need to enhance the energy efficiency of fossil fuels in production and utilization, to develop a diverse set of new and carbon-neutral energy sources for the future, and to maintain a robust basic research program in the chemical sciences so that the technical breakthroughs will happen to enable this future. In the midterm: . World energy demand will increase approximately 50 percent above 2002 levels. (Alexis Bell) . Fossil fuels will remain abundant and available as well as continue to provide most of the world's energy. (Nathan Lewis) There will be a drive toward fuels with higher hydrogen/carbon ratio, but balanced against the need to utilize the extensive low hydrogen/carbon coal resource base in the United States. (Venki Raman, Nathan Lewis) . Tighter environmental constraints will be imposed. (Nathan Lewis) Government-mandated carbon dioxide limits will be initiated, leading to a need for carbon dioxide sequestration technology and/or the introduction of large amounts of carbon-neutral energy. (Stephen Pacala) A real but limited role will be found for wind and hydro energy sources. (Nathan Lewis) . Nuclear, solar, and biomass energy will play a growing role in the nation's energy mix. (Patricia Baisden, Jiri Janata) Cost-effective hydrogen fuel cell technology for transportation and power will be developed. (John Wallace, James Katzer) . A significant penetration of vehicles with new high-efficient clear power sources will be seen in the transportation market. (John Wallace, James Katzer) Most hydrogen will be produced from fossil fuels.2 In the long-term: . World energy demand will rise to approximately two and a half times the present energy usage. (Nathan Lewis) . Fossil fuels like coal and natural gas will remain abundant and available, but a serious limitation on their use will arise because of worldwide constraints on carbon dioxide emissions. (Nathan Lewis, Alexis Bell) There will be a need for significant carbon-neutral energy. (Most of the presenters) . Fully developed carbon dioxide sequestration technology will be one of the important approaches to solving the energy problem. (Stephen Pacala) Coal and nuclear energy will continue to play a significant role in meeting world power demands. (Nathan Lewis, Alexis Bell) 2Venki Raman, in his presentation to the Energy & Transportation Workshop, noted that presently eighty percent of the hydrogen produced is made from natural gas steam methane generation.

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4 ENERGY AND TRANSPORTATION . Renewable energy (wind, biomass, geothermal, photovoltaics, and direct photon conversion for example, solar photovoltaic water splitting) will play an increasingly important role. (Nathan Lewis, Ralph Overend) Most of world's vehicles will run on hydrogen from a carbon-free source or other fuels that are carbon-neutral. (John Wallace, James Katzer, Venki Raman) New cost-effective solar technology will be widely available. (Nathan Lewis, Ralph Overend) Hydrogen and distributed electricity will be produced by solar energy, either through photovoltaic electrolysis or by direct solar photoelectrolysis. (Nathan Lewis, Ralph Overend) Many of the issues discussed in this report, from increased energy efficiency from fossil fuels, to reduction of pollution, to sequestration of carbon dioxide, to development of new materials for vehicle fabrication, to new low-cost renewable energy technologies, if not wholly chemical in nature, contain significant chemi- cal science content. As chemical scientists seek to address these issues, the cross- cutting nature of many of these challenges should be recognized. Many of the challenges in energy and transportation will be met with technologies that have broad applications in a number of different fields. By working with scientists and engineers in other disciplines, such as materials scientists, bioscientists, geolo- gists, electrical engineers, information scientists, mechanical engineers, and others, a multidimensional approach to these challenges will be accomplished- and the likelihood for comprehensive new solutions will increase significantly. The path will not be straightforward, however, particularly in the United States. Interest in and appreciation of the importance of science and technology are decreasing. Fewer U.S. students are entering technical careers. Energy re- search is decreasing significantly in both the private and public sectors. While this workshop and report do not address these issues, they must be resolved or the United States will be in jeopardy of not being able to meet its future energy and transportation requirements. The following challenges were identified resulting from the presentations and discussions at the Workshop. Although these challenges were identified as a result of the Workshop, final responsibility for these statements rests with the organizing committee. ENERGY Fossil fuels will remain an abundant and affordable energy resource well into the 21st century. Since potential limitations on carbon dioxide emis- sions may restrict their utilization in the long term, it is imperative that chemical sciences research and engineering focus on making significant

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EXECUTIVE SUMMARY s increases in the energy efficiency and chemical specificity of fossil fuel utilization.3 Professor Bell identified new multifunctional highly selective catalysts and membranes and corresponding process technologies as the key research areas where opportunities will exist for major steps forward. These new catalysts and materials will allow much greater process efficiency (reduced carbon dioxide) through operations at lower temperatures and pressures and also by combining multiple process functions (i.e., shape selectivity and oxidation) in a single cata- lyst particle, thus reducing the number of process units in a plant. These new materials and processes will increase the efficiency and environ- mental cleanliness of hydrocarbon production and refining and also enable refin- eries to produce chemically designed fuels for future vehicle power trains. These chemically designed fuels will play a key role in new power trains. These engines will require fuels that can optimize the efficiency of the entire power cycle while at the same time produce essentially no harmful exhaust. The best way to accom- plish this is by designing the engine and fuel interactively, and this will lead to more chemical specificity requirements on the fuel. Natural gas has tremendous potential for meeting the energy needs of the future because it has a high hydrogen/carbon ratio and can be con- verted to H2 and environmentally clean liquid fuels.4 Current technology for converting natural gas to liquid fuels is by Fischer- Tropsch Technology, which converts methane to syngas (CO and H2) and the syngas to liquids (the Fischer-Tropsch step). While there have been major advances in the technology in the past decade, it is much less energy efficient than today's refining processes. New catalysts, membranes, and processes are needed which will convert methane directly to H2 and liquid fuels without going through syngas. This would tremendously increase the energy efficiency of methane conversion. Liquid products from these processes are chemically pure, containing no heteroatoms (i.e., sulfur, nitrogen, metals) Management of atmospheric carbon dioxide levels will require seques- tration of carbon dioxide. Research and development into methods to cost effectively capture and geologically sequester carbon dioxide is required in the next 10 to 20 years.5 3Alexis T. Bell, University of California, Berkeley, presentation at the Workshop on Energy and Transportation. 4Alexis T. Bell, University of California, Berkeley, Nathan Lewis, California Institute of Tech- nology, presentations at the Workshop on Energy and Transportation. Stephen W. Pacala, Princeton University, presentation at the Workshop on Energy and Transpor- tation.

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6 ENERGY AND TRANSPORTATION As noted in Professor Pacala's presentation, effective management of the increasing anthropogenic output of carbon dioxide into the atmosphere will be a significant challenge for the chemical sciences and engineering over the next century. Development of sequestration technology to address this issue will require a thorough understanding of carbon dioxide chemistry and geochemistry along with an elaboration of the mechanisms involved in carbon dioxide absorp- tion, adsorption, and gas separation. Also, effective sequestration will require new engineering knowledge to capture and transport the carbon dioxide to the sequestration site most likely a geological reservoir. A more thorough under- standing of the geochem~cal, geological, and geophysical nature of the sequestra- tion site will be required to ensure that carbon dioxide does not escape over centuries of storage. Biomass has the potential to provide appreciable levels of fuels and elec- tric power, but an exceptionally large increase in field efficiency6 is needed to realize the huge potential of energy from biomass.7 Biologically based strategies for providing renewable energy can be grouped into two major categories: (1) those that use features of biological systems to convert sunlight into useful forms (e.g., power, fuels) but do not involve whole living plants, and (2) those involving growth of plants and processing of plant components into fuels and/or power. Both are very important. Long-term im- provements can be expected in the development of both biomass resources and the conversion technologies required to produce electric power, fuels, chemicals, materials, and other big-based products. As molecular genetics matures over the next several decades, for example, its application to biomass energy resources can be expected to significantly improve the economics of all forms of big-energy. Improvements in economics, in turn, will likely lead to increased efforts to develop new technologies for the integrated production of ethanol, electricity, and chemical products from specialized biomass resources. Near-term markets exist for corn-ethanol and the co-firing of coal-fired power plants. By the middle of the 21st century, global energy consumption will more than double from the present rate. To meet this demand under potential worldwide limits on carbon dioxide emissions, cost-effective solar energy must be developed.8 sin agriculture, field efficiency is the ratio of effective field capacity and theoretical field capacity. 7Alexis T. Bell, University of California, Berkeley, Nathan Lewis, California Institute of Technol- ogy, Ralph P. Overend, National Renewable Energy Laboratory, presentations at the Workshop on Energy and Transportation. Alexis T. Bell, University of California, Berkeley, Nathan Lewis, California Institute of Technol- ogy, Ralph P. Overend, National Renewable Energy Laboratory, presentations at the Workshop on Energy and Transportation.

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EXECUTIVE SUMMARY 7 At present consumption levels, the supply of carbon-based fuels will be suf- ficient to meet our energy needs for well over a century. However, as noted in both Professor Bell's and Professor Lewis' presentations, the anticipated growth in energy demand over the next century, combined with climate change concerns, will drive the increased use of alternative sources of carbon-neutral energy. While a number of potential sources of renewable energy show promise for meeting part of this increased demand, including wind, biomass, geothermal, and expanded use of hydroelectric sources, cost-effective solar power will likely be required to meet the largest portion of this demand. However, in order for use of solar power to increase substantially over the 21st century, new discoveries in photovoltaic and photochemical energy technologies must be made to reduce costs, increase conversion efficiency, and extend operating life. Advanced materials such as organic semiconductors and semiconducting polymers are needed to reduce energy costs from photovoltaics and make them competitive for electric power and hydrogen generation. Current silicon-based photovoltaics are highly efficient, but also very expensive. New technologies are needed to bring costs down. New photovoltaic materials and structures with very low cost-to-efficiency ratios are needed to produce a step change in the use of photovoltaic technology. For example, the use of grain boundary passivation with polycrystalline semiconduc- tor materials might lead to the replacement of expensive single crystal-based tech- nologies. The development of new, inexpensive, and durable materials for photoelectrochemical systems for direct production of hydrogen and electricity generation will be one of the main factors that will enable broad application of solar power to meet future energy needs. Widespread use of new, renewable, and carbon-neutral energy sources will require major breakthroughs in energy storage technologies.9 Development of these technologies is dependent, in part, on breakthroughs in the design of energy storage systems due to the intermittent nature of many forms of renewables. Batteries, whose basic design has remained relatively unchanged for over a century, need to be fundamentally reexamined, as they will play an important role in meeting future energy needs. For example, advances in nanotechnology and its use in three-dimensional electrochemical cells offer the possibility of increased energy density compared to conventional batteries, but these advances are still in the early stages of development. In addition, funda- mental research breakthroughs are needed on thin-film electrolytes in order to develop high-power-density batteries and fuel cells.l 9Nathan Lewis, California Institute of Technology, Henry S. White, University of Utah, presenta- tions to the Workshop on Energy and Transportation. that present fuel cell systems are being piloted for distributed generation backup power. This may provide another source of energy storage.

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8 ENERGY AND TRANSPORTATION For full public acceptance of nuclear power, issues such as waste disposal, reactor safety, economics, and nonproliferation must be addressed. Future energy consumption trends indicate the need for additional sources of carbon-neutral energy. No one source of power will be sufficient to meet all of the projected increase in future power needs. Dr. Baisden in her presentation noted that nuclear power offers a plentiful supply of energy that is free from local emissions and produces no carbon-based greenhouse gases. However, nuclear power is unique in that political considerations are as important as technical chal- lenges. One of the main technical challenges is waste management and disposal. Significant amounts of uranium can be reprocessed and reused in reactors, but this technology comes with significant concerns about nuclear proliferation and safety. Particularly in light of recent terrorist actions in the United States, the development of safe nuclear waste forms that not only will survive long-term repository storage but also allow secure transit to a repository remains an impor- tant priority. Another significant issue facing the U.S. is the growing shortage of nuclear technical expertise. This threatens the management of the United States' cur- rently installed nuclear capacity and certainly the development of the science and engineering needed to expand nuclear energy use in the future. The training situ- ation is dire in nuclear chemistry, radiochemistry, and nuclear engineering. To address this shortage reinvestment in the education system will be required. TRANSPORTATION Vehicle mass reduction, changes in basic vehicle architecture, and im- provements in power trains are key to improved vehicle efficiency. The development and use of new materials are crucial to improved fuel efficiency. Dr. Sachdev noted in his presentation that reductions in the body mass of passenger vehicles will depend to a great extent on the successful integration of new lightweight materials. The dual needs in these applications for materials that are both lightweight and strong continue to present challenges and oppor- tunities in the chemical sciences. The development of new polymers and nanocomposite materials will play an increasing role in vehicle mass reduction. The combination of high strength and light weight makes them ideal for many of these applications. Along with new Patricia A. Baisden, Lawrence Livermore National Laboratory, Jiri Janata, Georgia Institute of Technology, presentations to the Workshop on Energy and Transportation. i2James R. Katzer, ExxonMobil, Kathleen C. Taylor and Anil Sachdev, General Motors Corpora- tion, presentations to the Workshop on Energy and Transportation.

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EXECUTIVE SUMMARY 9 materials, manufacturing and recycling processes will have to be developed that are both cost-effective and environmentally effective. As with the development of new catalysts, effective new materials benefit from a thorough understanding of structure/property relationships. This involves multiscale modeling and experimental efforts in surface science, including morphology. Enabling the use of new materials will also require extensive devel- opment of new nano- and microfabrication techniques, including biodirected or self-assembly syntheses. Cost remains one of the main factors that determine both the need and the acceptance of new materials for applications in energy and transportation. In addition, passenger safety, which may be affected by the development of more lightweight vehicles, must also be taken into consideration. The imperative of low-cost, high-performance materials in the automotive industry will be driven by future environmental and corporate average fuel economy (CAFE) standards. Reduced material cost is key to widespread use of the proton exchange membrane (PEM) fuel celled As with other materials challenges, selective and energy-efficient separa- tions are a highly desirable characteristic in many areas of energy and transporta- tion research and engineering. Development of low-temperature, corrosion- resistant, thin membranes will further PEM development. However, development of new catalytic materials to replace the very expensive platinum in today's design is the most critical need.~4 Low-cost materials in fuel cells will be one of the key deciding factors in whether the United States readily transitions to a hydrogen economy. The lack of hydrogen generation, transportation, and storage infrastruc- ture presents one of the main challenges to introducing hydrogen into the mass market as a transportation fuel and energy carriers Effective hydrogen management and creation of the needed infrastructure will both be key to widespread adoption of hydrogen fuel cells to meet the nation' s energy needs for transportation and power. The challenges are great. New- generation technology is needed in the short- to midterm for hydro-carbon based local refueling sites. In the long term, science and technology will have to be developed to generate hydrogen from carbon-free sources such as water, or at a minimum from carbon neutral sources. Whether this new energy source is based i3John R. Wallace, Ford Motor Company, presentation to the Workshop on Energy and Transpor- tation. i4A complementary goal to replacing expensive Pt in today's design is to develop catalysts with reduced Pt loading. i5Venki Raman, Air Products and Chemicals, presentation to the Workshop on Energy and Transportation.

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10 ENERGY AND TRANSPORTATION on nuclear, solar, or something that remains undiscovered, it will be one of the largest technical challenges the chemical sciences has ever undertaken. Another significant challenge to effective hydrogen management is the devel- opment of efficient hydrogen storage, both onboard the vehicle and at a hydrogen generation facility. As with many other challenges, effective hydrogen storage is a crosscutting one that will require breakthroughs in a number of research areas. Progress is being made with metal hydrides and carbon nanotubes but a com- mercial solution is a long way off. New materials will be key. These technical challenges regarding hydrogen presently hinder widespread commercial use of hydrogen fuel cell technology for transportation and power. Until these challenges are met, it is unlikely that fuel-cell-powered vehicles will ever make up a significant portion of the passenger vehicle market. CROSSCUTTING Development of new, less expensive, more selective chemical catalysts is essential to achieving many challenges in both energy and transportation. Catalysts are expected to play a role in virtually every challenge where chemi- cal transformations are a key component, as evidenced by the fact that virtually every presenter at the workshop mentioned catalysis. The development of new catalysts to solve challenges in energy and transportation will require the ability to design catalysts for specific needs. Utilization of new materials, nanotech- nology, new analytical tools, and advanced understanding of structure/property relationships will create major catalytic advances. One of the major areas where these advances are needed is in controlling nitrogen oxide emissions from lean- burn engines and nitrogen oxide from coal power plants. Others are increased energy efficiency of fossil fuel processes, delivery of chemically designed fuels to new vehicle power systems, and direct conversion of natural gas into liquid fuels and hydrogen. Another is the discovery of less expensive catalysts for the electroreduction of oxygen and the oxidation of fuels that can play an important role in fuel cells. Catalysts for promoting oxygen and hydrogen evolution from water are also important in the design of photoelectrochemical systems. Because this report is based only on a two-day workshop, details of chemical science research and engineering programs need to be further developed for each finding. The workshop's organizing committee suggests that the National Re- search Council pursue development of these detailed programs because of the importance of energy and transportation to the nation.