Lighting the Way: Toward a Sustainable Energy Future

  • AuthorInterAcademies Council
  • Release Date1 October 2007
  • Copyright2007
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Commissioned by the governments of Brazil and China, this report identifies a scientific consensus framework for directing global energy development.  It lays out the science, technology and policy roadmap for developing energy resources to drive economic growth in both industrialized and developing countries while also securing climate protection and global development goals.  The report was produced by a study panel of 15 world-renowned energy experts, co-chaired by Nobel Laureate Steven Chu, Director of the Lawrence Berkeley National Lab in the United States, and José Goldemberg, former Secretary of State for the Environment for the State of São Paulo, Brazil.

Lighting the way establishes the best practices for a global transition to a clean, affordable and sustainable energy supply in both developing and developed countries. The report addresses incentives that can accelerate the development of innovative solutions, provides recommendations for financial investments in research and development and explores other transition pathways that can transform the landscape of energy supply and demand around the globe.

In addressing mitigation of the environmental impacts of energy generation and use, Lighting the way informs global action on climate change, such as implementation of the Kyoto Protocol, agenda setting for the Asia-Pacific Partnership on Clean Development and Climate, and ongoing multinational talks on future global action to reduce greenhouse emissions.

Lighting the way also confronts the unequal access to energy experienced by the one-third of the world’s population without access to basic energy services, and makes recommendations for addressing this disparity as well as for promoting national and global energy security.

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As recognized in 1997 by the Kyoto Protocol, achieving a sustainable energy future presents an urgent challenge for the 21st century. Current patterns of energy resources and energy usage are proving detrimental to the long-term welfare of humanity. The integrity of essential natural systems is already at risk from climate change caused by the atmospheric emissions of greenhouse gases. At the same time, basic energy services are currently unavailable to a third of the world’s people, and more energy will be essential for equitable, worldwide sustainable development. The national and global energy security risks are further exacerbated by an escalating energy cost and by the competition for unevenly distributed energy resources.

This global problem requires global solutions. Thus far, insufficient advantage has been taken of the world’s leading scientists and their major institutions, even though these institutions are a powerful resource for communicating across national boundaries and for reaching agreement on rational approaches to long-term problems of this kind. The world’s academies of science and of engineering—whose judgments are based on objective evidence and analysis—have the respect of their national governments but are not government-controlled. Thus, for example, scientists everywhere can generally agree even when their governments have different agendas. Many political leaders recognize the value of basing their decisions on the best scientific and technological advice, and they are increasingly calling upon their own academies of sciences and engineering to provide this advice for their nation. But the possibility and value of such advice at the international level—from an analogous source based on associations of academies—is a more recent development. In fact, only with the establishment of the InterAcademy Council (IAC) in 2000 did accessing such advice become a straightforward matter. Thus far, three major reports have been released by the InterAcademy Council: on institutional capacity building in every nation for science and technology (S&T), on African agriculture, and on women for science.

At the request of the Governments of China and Brazil, and with strong support from United Nations Secretary-General, Mr. Kofi Annan, the IAC Board has now harnessed the expertise of scientists and engineers throughout the world to produce Lighting the Way: Toward a Sustainable Energy Future. Here, we call special attention to three of the report’s important messages.

First, science and engineering provide critical guiding principles for achieving a sustainable energy future. As the report states, ‘science provides the basis for a rational discourse about trade-offs and risks, for selecting research and development (R&D) priorities, and for identifying new opportunities—openness is one of its dominant values. Engineering, through the relentless optimization of the most promising technologies, can deliver solutions—learning by doing is among its dominant values. Better results will be achieved if many avenues are explored in parallel, if outcomes are evaluated with actual performance measures, if results are reported widely and fully, and if strategies are open to revision and adaptation.’

Second, achieving a sustainable energy future will require an intensive effort at capacity building, as well as the participation of a broad array of institutions and constituencies. The report emphasizes that ‘critical to the success of all the tasks ahead are the abilities of individuals and institutions to effect changes in energy resources and usage. Capacity building of individual expertise and institutional effectiveness must become an urgent priority of all principal actors—multinational organizations, governments, corporations, educational institutions, non-profit organizations, and the media. Above all, the general public must be provided with sound information about the choices ahead and the actions required for achieving a sustainable energy future.’

Third, although achieving a sustainable energy future requires long-range approaches, given the dire prospect of global climate change, the Study Panel urges that the following be done expeditiously and simultaneously:

    Concerted efforts should be mounted for improving energy efficiency and reducing the carbon intensity of the world economy, including the worldwide introduction of price signals for carbon emissions with consideration of different economic and energy systems in individual countries.
    Technologies should be developed and deployed for capturing and sequestering carbon from fossil fuels, particularly coal.
    Development and deployment of renewable energy technologies should be accelerated in an environmentally responsible way.

Also urgent as a moral, social, and economic imperative, the poorest people on this planet—who primarily reside in developing countries—should be supplied with modern, efficient, environmentally friendly and sustainable energy services. The scientific, engineering, and medical academies of the world, in partnership with the United Nations and many other concerned institutions and individuals, are poised to work together to help meet this urgent challenge.

We thank all of the Study Panel members, reviewers, and the two distinguished review monitors who contributed to the successful completion of this report. Special appreciation is due to the Study Panel Co-Chairs and staff who put so much time and devotion into ensuring that the final product would make a difference.

The InterAcademy Council gratefully acknowledges the leadership exhibited by the Government of China, the Government of Brazil, the William and Flora Hewlett Foundation, the Energy Foundation, the German Research Foundation (DFG), and the United Nations Foundation, which provided the financial support for the conduct of the study and the printing and distribution of this report. We are also grateful to the following organizations for their contributions in hosting regional IAC energy workshops: the Brazilian Academy of Sciences, the Chinese Academy of Sciences, the French Academy of Sciences, the Indian National Science Academy, and the Science Council of Japan.

Past President, U.S. National Academy of Sciences
Co-Chair, InterAcademy Council

LU Yongxiang
President, Chinese Academy of Sciences
Co-Chair, InterAcademy Council


 Study Panel

United States), Director, Lawrence Berkeley National Laboratory & Professor of Physics and Professor of Molecular and Cellular Biology University of California, Berkeley, California, USA
José GOLDEMBERG (Brazil), Professor, University of São Paulo, São Paulo, Brazil

Shem ARUNGU OLENDE (Kenya), Secretary-General, African Academy of Sciences & Chairman and Chief Executive Officer, Quecosult Ltd., Nairobi, Kenya
Mohamed EL-ASHRY (Egypt), Senior Fellow, UN Foundation, Washington D.C., USA
Ged DAVIS (United Kingdom), Co-President, Global Energy Assessment, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria
Thomas JOHANSSON (Sweden), Professor of Energy Systems Analysis and Director, International Institute for Industrial Environmental Economics (IIIEE), University of Lund, Sweden
David KEITH (Canada), Director, ISEEE Energy and Environmental Systems Group, and Professor and Canada Research Chair of Energy and the Environment, University of Calgary, Canada
LI Jinghai (China), Vice President, Chinese Academy of Sciences, Beijing, China
Nebosja NAKICENOVIC (Austria), Professor of Energy Economics, Vienna University of Technology, Vienna, Austria & Leader of Energy and Technology Programs, IIASA (International Institute for Applied Systems Analysis), Laxenburg, Austria
Rajendra PACHAURI (India), Director-General, The Energy & Resources Institute, New Delhi, India & Chairman, Intergovernmental Panel on Climate Change
Majid SHAFIE-POUR (Iran), Professor and Board member, Faculty of Environment, University of Tehran, Iran
Evald SHPILRAIN (Russia), Head, Department of Energy and Energy Technology, Institute for High Temperatures, Russian Academy of Sciences, Moscow, Russian Federation
Robert SOCOLOW (United States), Professor of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA
Kenji YAMAJI (Japan), Professor of Electrical Engineering, University of Tokyo, Member of Science Council of Japan, Vice-Chair of IIASA Council, Chairman of the Green Power Certification Council of Japan, Tokyo, Japan
YAN Luguang (China), Chairman, Scientific Committee of Institute of Electrical Engineering, Chinese Academy of Sciences & Honorary President, Ningbo University, Beijing, China

Jos van RENSWOUDE, Study Director
Dilip AHUJA, Consultant
Marika TATSUTANI, Writer/Editor
Stéphanie A. JACOMETTI, Communications Coordinator



Human prosperity has been intimately tied to our ability to capture, collect, and harness energy. The control of fire and the domestication of plants and animals were two of the essential factors that allowed our ancestors to transition from a harsh, nomadic existence into stable, rooted societies that could generate the collective wealth needed to spawn civili­zations. For millennia, energy in the form of biomass and fossilized biomass was used for cook­ing and heating, and for the creation of materials that ranged from bricks to bronze. Despite these developments, relative wealth in virtually all civiliza­tions was fundamentally defined by access to and control over energy, as measured by the number of animal and humans that served at the beck and call of a particular individual.

The Industrial Revolution and all that followed have propelled an increasingly larger fraction of humanity into a dramatically different era. We go to the local market in automobiles that generate the pull of hundreds of horses, and we fly around the world with the power of a hundred thousand horses. Growing numbers of people around the world can take for granted that their homes will be warm in the winter, cool in the summer, and lit at night. The widespread use of energy is a fundamental reason why hundreds of millions of people enjoy a standard of living today that would have been unimaginable to most of humanity a mere century ago.

What has made all this possible is our ability to use energy with ever increasing dexterity. Science an technology have given us the means to obtain and exploit sources of energy, primarily fossil fuel, so that the power consumption of the world today is the equivalent of over seventeen billion horses working 24 hours per day, 7 days per week, 365 days a year. Put another way, the amount of energy needed to keep a human being alive varies between 2,000 and 3,000 kilocalories per day. By contrast, average per capita energy consumption in the United States is approxi­mately 350 billion joules per year, or 230,000 kilocal­ories per day. Thus, the average American consumes enough energy to meet the biological needs of 100 people, while the average citizen in OECD countries uses the energy required to sustain approximately 50 people. By comparison, China and India currently consume approximately 9–30 times less energy per person than the United States. The worldwide consumption of energy has nearly doubled between 1971 and 2004, and is expected to grow another 50 percent by 2030, as developing countries move—in a business-as-usual scenario—toward an economic prosperity deeply rooted in increased energy use.

The path the world is currently taking is not sustainable: there are costs associated with the inten­sive use of energy. Heavy reliance on fossil fuels is causing environmental degradation at the local, regional, and global levels. Climate change, in particular, poses global risks and challenges that are perhaps unprecedented in their magnitude, complexity, and difficulty. At the same time, secur­ing access to vital energy resources, particularly oil and natural gas, has become a powerful driver in geo-political alignments and strategies. Finally, if current trends continue, inequitable access to energy, particularly for people in rural areas of devel­oping countries, and the eventual exhaustion of inex­pensive oil supplies could have profound impacts on international security and economic prosperity.

While the current energy outlook is very sobering we believe that there are sustainable solutions to the energy problem. A combination of local, national, and international fiscal and regulatory polices can greatly accelerate efficiency improvements, which remain in many cases the most cost-effective and readily implemented part of the solution. Significant efficiency gains were achieved in recent years and more can be obtained with policy changes that encourage the development and deployment of better technologies. For developing countries with rapidly growing energy consumption, ‘leapfrogging’ past the wasteful energy trajectory historically followed by today’s industrialized countries is in their best economic and societal interests. Providing assistance to these countries aimed at promoting the introduction of efficient and environmentally friendly energy technologies as early as possible should therefore be an urgent priority for the inter­national community.

A timely transition to sustainable energy systems also requires policies that drive toward optimal soci­etal choices, taking into account both the short- and long-term consequences of energy use. Discharging raw sewage into a river will always be less expensive at a micro-economic level than first treating the waste, especially for ‘up-stream’ polluters. At a macro scale, however, where the long-term costs to human health, quality of life, and the environment are folded into the calculation, sewage treatment clearly becomes the low-cost option for society as a whole. In the case of climate change, the predicted conse­quences of continued warming include a massive reduction of water supplies in some parts of the world, especially those that rely on the steady run-off of water from glaciers; the spread of malaria, chol­era, and other diseases whose vectors or pathogens are temperature- and moisture-dependent; increased devastation from extreme weather events such as floods, droughts, wildfires, typhoons, and hurri­canes; permanent displacement of tens to hundreds of millions of people due to rising sea levels; and significant loss of biodiversity.

Meanwhile, other types of emissions associated with common forms of energy use today impose significant adverse health impacts on large numbers of people around the world—creating risks and costs that are often not captured in energy market choices or policy decisions. Thus, it becomes critical to consider the additional costs of mitigating these impacts when attempting to assess the true low-cost option in any long-term, macro-economic analysis of energy use and production. The cost of carbon emis­sions and other adverse impacts of current modes of energy use must be factored into market and policy decisions.

In addition to extensive energy efficiency enhance­ments and rapid deployment of low-carbon technolo­gies, including advanced fossil-fuel systems with carbon capture and sequestration and nuclear energy, a sustainable energy future will be more readily attainable if renewable energy sources become a significant part of the energy supply port­folio. Science and technology are again essential to delivering this part of the solution. Significant improvements in our ability to convert solar energy into electricity are needed, as are economical, large-scale technologies for storing energy and transmit­ting it across long distances. Improved storage and transmission technologies would allow intermittent renewable sources to play a greater role in supplying the world’s electricity needs. At the same time, effi­cient methods of converting cellulosic biomass into high-quality liquid fuels could greatly reduce the carbon footprint of the world’s rapidly growing trans­portation sector and relieve current supply pressures on increasingly precious petroleum fuels.

At this point, much has been written about the sustainable energy problem and its potential solu­tions. The defining feature of this report by the InterAcademy Council (IAC) is that it was developed by a study panel that brought together experts nomi­nated by over ninety national academies of science around the world. Members of the panel in turn drew upon the expertise of colleagues within and outside their own countries, so that the resulting report—which was further informed by a series of workshops held in different parts of the world and by numerous commissioned studies—represents a uniquely international and diverse perspective. It is our hope that the conclusions and actionable recom­mendations contained in Chapter 5, The Case for Immediate Action, will provide a useful roadmap for navigating the energy challenges we confront this century. Effecting a successful transition to sustain­able energy systems will require the active and informed participation of all for whom this report is intended, from citizens and policymakers to scien­tists, business leaders, and entrepreneurs—in indus­trialized and developing countries alike.

It has also become evident to us, in surveying the current energy situation from multiple vantage points and through different country lenses, that it will be critical to expand and improve the capacity of international institutions and actors to respond effectively to global challenges and opportunities. Accordingly, we have personally recommended that the UN Secretary General appoint a small committee of experts who can advise him and member nations on implementing successful technologies and strate­gies for promoting sustainable energy outcomes. By identifying promising options and recommending modifications, where necessary, to suit different country contexts, this committee could accelerate the global dissemination of sustainable energy solu­tions. At the same time, it could promote a dialogue with industrial stakeholders and policymakers to identify the most effective incentives, policies, and regulations that would lead to the implementation of those solutions. Appropriately designed changes in government policy can, like the rudder of a ship, be used to steer a shift in direction that produce enor­mous course changes over time. We have seen examples where relatively modest government poli­cies in our own countries have led to great successes—from California’s success in holding constant the electricity consumption per capita over the last thirty years (at a time when electricity use in the rest of the United States had grown by sixty percent) to Brazil’s success in nurturing a pioneering biofuels industry that has leapt ahead of far more economically developed countries.

In sum, we believe that aggressive support of energy science and technology, coupled with incen­tives that accelerate the concurrent development and deployment of innovative solutions, can transform the entire landscape of energy demand and supply. This transformation will make it possible, both tech­nically and economically, to elevate the living condi­tions of most of humanity to the level now enjoyed by a large middle class in industrialized countries while substantially reducing the environmental and energy-security risks associated with current patterns of energy production and use. What the world does in the coming decade will have enormous consequences that will last for centuries; it is impera­tive that we begin without further delay On December 10, 1950, William Faulkner, the Nobel Laureate in Literature, spoke at the Nobel Banquet in Stockholm:

… I believe that man will not merely endure: he will prevail. He is immortal, not because he alone among creatures has an inexhaustible voice, but because he has a soul, a spirit capable of compas­sion and sacrifice and endurance.

With these virtues, the world can and will prevail over this great energy challenge.

Steven CHU
Study Panel Co-Chair

Study Panel Co-Chair


3 - These and other impacts are predicted with a high level of confidence in Climate Change 2007: Impacts, Adaptation and Vulnerability.
Contribution of the Working Group II to the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom and New York, NY: Cambridge University Press, 2007.


 Report review

This report was externally reviewed in draft form by 15 internationally renowned experts chosen for their diverse perspectives, technical knowledge, and geographical representation, in accordance with procedures approved by the IAC Board. The purpose of this independent review was to provide candid and critical comments that would help the IAC to produce a sound report that met the IAC standards for objectivity, evidence, and responsiveness to the study charge. The review procedure and draft manuscript remain confidential to protect the integrity of the deliberative process. The IAC wishes to thank the following individuals for their review of this report:
Eric ASH, former Rector, Imperial College, London,UK
Rangan BANERJEE, Professor, Energy Systems Engineering, Indian Institute of Technology-Bombay, Mumbai, India
Edouard BRÉZIN, Professor of Physics, Ecole Normale Supérieure, Paris, France; and former President, French Academy of Sciences
CHENG Yong, Director and Professor, Guangzhou Institute of Energy Conversion, Guangdong, China
Adinarayantampi GOPALAKRISHNAN, Professor of Energy & Security, ASCI, Hyderabad, India
Jack JACOMETTI, Vice President, Shell Oil Corporation, London, UK
Steven KOONIN, Chief Scientist, British Petroleum P.L.C., London, UK
LEE Yee Cheong, Member, Energy Commission of Malaysia, Kuala Lumpur; and former President, World Federation of Engineering Organizations
Isaias C. MACEDO, Interdisciplinary Center for Energy Planning, State University of Campinas, São Paulo, Brazil
Maurice STRONG, former Under-Secretary General of the United Nations; Secretary General, 1992 UN Conference on Environment and Development
Maurício TOLMASQUIM, President, Energy Research Company (EPE), Rio de Janeiro, Brazil
Engin TURE, Associate Director, International Centre for Hydrogen Energy Technologies-UNIDO, Istanbul, Turkey
Hermann-Josef WAGNER, Professor of Engineering, Ruhr-University Bochum, Germany
Dietrich H. WELTE, former Professor of Geology, RWTH Aachen University; Founder, IES GmBH Integrated Exploration Systems, Aachen, Germany
Jacques L. WILLEMS, Professor Emeritus, Faculty of Engineering, Ghent University, Ghent, Belgium

Although the reviewers listed above provided many constructive comments and suggestions, they were not asked to endorse the conclusions and recommendations, nor did they see the final draft of the report before its release.

The review of this report was overseen by two review monitors:
Ralph J. CICERONE, President, United States National Academy of Sciences, Washington, DC, USA
R. A. MASHELKAR, President, Indian National Science Academy; and Bhatnagar Fellow, National Chemical Laboratory, Pune, India

Appointed by the IAC Co-Chairs, the review monitors were responsible for ascertaining that the independent examination of this report was carried out in accordance with IAC procedures and that all review comments were carefully considered. However, responsibility for the final content of this report rests entirely with the authoring Study Panel and the InterAcademy Council.



The Study Panel is grateful to the participants in the seven consultative workshops held during the course of this project. These workshop participants provided valuable insights that enabled the identification of the major strategic challenges and opportunities, which effectively helped the Study Panel in guiding its deliberations and in drafting this report.

The workshop participants include:

    Durban Workshop. Robert Baeta, Douglas Banks, Abdelfattah Barhdadi, Osman Benchikh, MosadElmissiry, Joseph Essandoh-Yeddu, Moses Haimbodi, Manfred Hellberg, I.P. Jain, Dirk Knoesen, Isaias C. Macedo, Cédric Philibert, Youba Sokona,Samir Succar, Annick Suzor-Weiner, and Brian Williams;Beijing Workshop. Paul Alivisatos, Bojie Fu, E. Michael Campbell, Chongyu Sun, Charles Christopher, Dadi Zhou, Fuqiang Yang, Hao Wen, Hin Mu, Hu Min, Kazunari Domen, Kebin He,Luguang Yan, Shuanshi Fan, Jack Siegel, Peng Chen, Qingshan Zhu, Xiu Yang, Xudong Yang, Wei Qin, Wenzhi Zhao, Yi Jiang, Yu Joe Huang, Zheng Li, Zhenyu Liu, and Zhihong Xu;

    Berkeley Workshop. Paul Alivisatos, E. Michael Campbell, Mildred Dresselhaus, Kazunari Domen, Jeffrey Greenblatt, Adam Heller, Robert Hill, Martin Hoffert, Marcelo Janssen, Jay Keasling, Richard Klausner, Banwari Larl, Nathan S. Lewis, Jane Long, Stephen Long, Amory Lovins, Thomas A. Moore, Daniel Nocera, Melvin Simon, Christopher Somerville, John Turner, Craig Venter, and Zhongxian Zhao
    Rio de Janeiro Workshop. Alfesio L. Braga, Kamala Ernest, André Faaij, Patrícia Guardabassi, Afonso Henriques, Gilberto Jannuzzi, Henry Josephy, Jr., Eric D. Larson, Lee Lynd, José R. Moreira, Marcelo Poppe, Fernando Reinach, Paulo Saldiva, Alfred Szwarc, Suani Coelho Teixeira, Boris Utria, Arnaldo Walter, and Brian Williams;
    New Delhi Workshop. Alok Adholeya, Shoibal Chakravarty, P. Chellapandi, Ananth Chikkatur,K. L.Chopra, S.P.Gon Choudhury, Piyali Das, Sunil Dhingra, I. V. Dulera, H. P. Garg, A. N. Goswami, H. B. Goyal, R.B. Grover, A. C. Jain, S. P. Kale, Ashok Khosla, L. S. Kothari, Sameer Maithel, Dinesh Mohan, J. Nanda, C. S. R. Prasad, S. Z. Qasim, Baldev Raj, Baldev Raj, Surya P. Sethi, M. P. Sharma, R. P. Sharma, R. R. Sonde, S. Sriramachari, G. P. Talwar, A. R. Verma, R. Vijayashree, and Amit Walia;
    Paris Workshop. Edouard Brézin, Bernard Bigot, Leonid A. Bolshov, Alain Bucaille, Ayse Erzan,Harold A. Feiveson, Sergei Filippov, Karsten Neuhoff, Lars Nilsson, Martin Patel, Peter Pearson, Jim Platts, Mark Radka, Hans-Holger Rogner, Oliver Schaefer, and Bent Sorensen; and the
    Tokyo Workshop. Akira Fujishima, Hiromichi Fukui, Hideomi Koinuma, Kiyoshi Kurokawa,Takehiko Mikami, Chikashi Nishimura, Zempachi Ogumi, Ken-ichiro Ota, G. R. Narasimha Rao, and Ayao Tsuge, and Harumi Yokokawa.

The Study Panel is also grateful to the Brazilian Academy of Sciences, the Chinese Academy of Sciences, the French Academy of Sciences, the Indian National Science Academy, and the Science Council of Japan for their contributions in hosting the regional IAC energy workshops.

The Study Panel appreciates the contribution of authors who prepared background papers that, together with the consultative workshops, provided the essential building blocks for the report. Those involved were John Ahearne, Robert U. Ayres, Isaias de Carvalho Macedo, Vibha Dhawan, J. B. Greenblatt, Jiang Yi, Liu Zhen Yu, Amory B. Lovins, Cedric Philibert, K. Ramanathan, Jack Siegel, Xu Zhihong, Qingshan Zhu, and Roberto Zilles.

The Study Panel is most grateful for the extraordinary contributions of Jos van Renswoude, Study Director, for organizing the entire study panel process, and along with Dilip Ahuja, Consultant, and Marika Tatsutani, Writer/Editor, for the successful completion of the report writing process.

The InterAcademy Council (IAC) Secretariat and the Royal Netherlands Academy of Arts and Sciences (KNAW) in Amsterdam, where IAC is headquartered, provided guidance and support for this study. In this regard, special mention is made of the assistance provided by John P. Campbell, IAC Executive Director; Albert W. Koers, IAC General Counsel; Stéphanie Jacometti, Communications Coordinator; and Margreet Haverkamp, Shu-Hui Tan, Floor van den Born, Ruud de Jong, and Henrietta Beers of the IAC Secretariat. Ellen Bouma, Publication Designer, and Sheldon I. Lippman, Editorial Consultant, prepared the final manuscript for publication.

The Study Panel gratefully acknowledges the leadership exhibited by the Government of China, the Government of Brazil, the William and Flora Hewlett Foundation, the Energy Foundation, the German Research Foundation (DFG), and the United Nations Foundation, which provided the financial support for the conduct of the study and the printing and distribution of this report.

Last but by no means least, the Study Panel thanks the InterAcademy Council Board and especially Bruce Alberts and Lu Yongxiang, IAC Co-Chairs, for providing the opportunity to undertake this important study.


 Executive Summary

Making the transition to a sustainable energy future is one of the central challenges humankind faces in this century. The concept of energy sustainability encompasses not only the imperative of securing adequate energy to meet future needs, but doing so in a way that (a) is compatible with preserving the underlying integrity of essential natural systems, including averting dangerous climate change; (b) extends basic energy services to the more than 2 billion people worldwide who currently lack access to modern forms of energy; and (c) reduces the security risks and potential for geopolitical conflict that could otherwise arise from an escalating competition for unevenly distributed energy resources.

The Sustainable Energy Challenge

The task is as daunting as it is complex. Its dimensions are at once social, technological, economic, and political. They are also global. People everywhere around the world play a role in shaping the energy future through their behavior, lifestyle choices, and preferences. And all share a significant stake in achieving sustainable outcomes.

The momentum behind current energy trends is enormous and will be difficult to check in the context of high levels of existing consumption in many industrialized countries; continued population growth; rapid industrialization in developing countries; an entrenched, capital-intensive and long-lived energy infrastructure; and rising demand for energy-related services and amenities around the world. Although wide disparities exist in per capita energy consumption at the country level, relatively wealthy households everywhere tend to acquire similar energy-using devices. Therefore, the challenge and the opportunity exists—in industrialized and developing countries alike—to address resulting energy needs in a sustainable manner through effective demand- and supply-side solutions.

The prospects for success depend to a significant extent on whether nations can work together to ensure that the necessary financial resources, technical expertise, and political will are directed to accelerating the deployment of cleaner and more efficient technologies in the world’s rapidly industrializing economies. At the same time, current inequities that leave a large portion of the world’s population without access to modern forms of energy and therefore deprived of basic opportunities for human and economic development must also be addressed.

This could be achieved without compromising other sustainability objectives, particularly if simultaneous progress is achieved toward introducing new technologies and reducing energy intensity elsewhere throughout the world economy. The process of shifting away from a business-as-usual trajectory will necessarily be gradual and iterative: because essential elements of the energy infrastructure have an expected life on the order of one to several decades, dramatic changes in the macroscopic energy landscape will take time. The inevitable lag in the system, however, also creates grounds for great urgency. In light of growing environmental and energy security risks, significant global efforts to transit to a different landscape must begin within the next ten years. Delay only increases the difficulty of managing problems created by the world’s current energy systems, as well as the likelihood that more disruptive and costly adjustments will need to be made later.

The case for urgent action is underscored when the ecological realities, economic imperatives, and resource limitations that must be managed over the coming century are viewed in the context of present world energy trends. To take just two dimensions of the challenge—oil security and climate change—current forecasts by the International Energy Agency in its 2006 World Energy Outlook suggest that a continuation of business-as-usual trends will produce a nearly 40 percent increase in world oil consumption (compared to 2005 levels) and a 55 percent increase in carbon dioxide emissions (compared to 2004 levels) over the next quarter century (that is, by 2030). In light of the widely held expectation that relatively cheap and readily accessible reserves of conventional petroleum will peak over the next few decades and mounting evidence that the responsible mitigation of climate-change risks will require significant reductions in global greenhouse gas emissions within the same timeframe, the scale of the mismatch between today’s energy trends and tomorrow’s sustainability needs speaks for itself.

For this report, the Study Panel examined the various technology and resource options that are likely to play a role in the transition to a sustainable energy future, along with some of the policy options and research and development priorities that are appropriate to the challenges at hand. Its principal findingsin each of these areas are summarized below followed by nine major conclusions with actionable recommendations reached by the Study Panel.

Energy Demand and Efficiency

Achieving sustainability objectives will require changes not only in the way energy is supplied, but in the way it is used. Reducing the amount of energy required to deliver various goods, services, or amenities is one way to address the negative externalities associated with current energy systems and provides an essential complement to efforts aimed at changing the mix of energy supply technologies and resources. Opportunities for improvement on the demand side of the energy equation are as rich and diverse as those on the supply side, and frequently offer significant near-term and long-term economic benefits. Widely varying per capita or per gross domestic product (GDP) levels of energy consumption across countries with comparable living standards—though certainly partly attributable to geographic, structural, and other factors—suggest that the potential to reduce energy consumption in many countries is substantial and can be achieved while simultaneously achieving significant quality-of-life improvements for the world’s poorest citizens. For example, if measures of social welfare, such as the Human Development Index (HDI), are plotted against per capita consumption of modern forms of energy, such as electricity, one finds that some nations have achieved relatively high levels of wellbeing with much lower rates of energy consumption than other countries with a similar HDI, which is composed of health, education, and income indicators. From a sustainability perspective then, it is both possible and desirable to maximize progress toward improved social well-being while minimizing concomitant growth in energy consumption.

In most countries, energy intensity—that is, the ratio of energy consumed to goods and services provided—has been declining, albeit not at a rate sufficient to offset overall economic growth and reduce energy consumption in absolute terms. Boosting this rate of intensity decline should be a broadly held, public policy priority. From a purely technological standpoint, the potential for improvement is clearly enormous: cutting-edge advances in engineering, materials, and system design have made it possible to construct buildings that demonstrate zero-net energy consumption and vehicles that achieve radically lower gasoline consumption per unit of distance traveled. The challenge, of course, is to reduce the cost of these new technologies while overcoming a host of other real-world obstacles—from lack of information and split incentives to consumer preferences for product attributes at odds with maximizing energy efficiency—that often hamper the widespread adoption of these technologies by the marketplace.

Experience points to the availability of policy instruments for overcoming barriers to investments in improved efficiency even when such investments, based on energy and cost considerations alone, are highly cost-effective. The improvements in refrigerator technology that occurred as a result of appliance efficiency standards in the United States provide a compelling example of how public policy intervention can spur innovation, making it possible to achieve substantial efficiency gains while maintaining or improving the quality of the product or service being provided. Other examples can be found in efficiency standards for buildings, vehicles, and equipment; in addition to information and technical programs and financial incentive mechanisms.

Energy Supply

The world’s energy supply mix is currently dominated by fossil fuels. Now, coal, petroleum, and natural gas together supply roughly 80 percent of global primary energy demand. Traditional biomass, nuclear energy, and large-scale hydropower account largely for the remainder. Modern forms of renewable energy play only a relatively small role at present (on the order of a few percent of the world’s current supply mix). Energy security concerns—particularly related to the availability of relatively cheap, conventional supplies of petroleum and, to a lesser extent, of natural gas—continue to be important drivers of national energy policy in many countries and a potent source of ongoing geopolitical tensions and economic vulnerability. Nevertheless, environmental limits, rather than supply constraints, seem likely to emerge as the more fundamental challenge associated with continued reliance on fossil fuels. World coal reserves alone are adequate to fuel several centuries of continued consumption at current levels and could provide a source of petroleum alternatives in the future. Without some means of addressing carbon emissions, however, continued reliance on coal for a large share of the world’s future energy mix would pose unacceptable climate-change risks.

Achieving sustainability objectives will require significant shifts in the current mix of supply resources toward a much larger role for low-carbon technologies and renewable energy sources, including advanced biofuels. The planet’s untapped renewable energy potential, in particular, is enormous and widely distributed in industrialized and developing countries alike. In many settings, exploiting this potential offers unique opportunities to advance both environmental and economic development objectives.

Recent developments, including substantial policy commitments, dramatic cost declines, and strong growth in many renewable energy industries are promising. However, significant technological and market hurdles remain and must be overcome for renewable energy to play a significantly larger role in the world’s energy mix. Advances in energy storage and conversion technologies and in enhancing long-distance electric transmission capability could do much to expand the resource base and reduce the costs associated with renewable energy development. Meanwhile, it is important to note that recent substantial growth in installed renewable capacity worldwide has been largely driven by the introduction of aggressive policies and incentives in a handful of countries. The expansion of similar commitments to other countries would further accelerate current rates of deployment and spur additional investment in continued technology improvements.

In addition to renewable means of producing electricity, such as wind, solar, and hydropower, biomassbased fuels represent an important area of opportunity for displacing conventional petroleum-based transportation fuels. Ethanol from sugar cane is already an attractive option, provided reasonable environmental safeguards are applied. To further develop the world’s biofuels potential, intensive research and development efforts to advance a new generation of fuels based on the efficient conversion of lignocellulosic plant material are needed. At the same time, advances in molecular and systems biology show great promise for generating improved biomass feedstocks and much less energy-intensive methods of converting plant material into liquid fuel, such as through direct microbial production of fuels like butanol.

Integrated bio-refineries could, in the future, allow for the efficient co-production of electric power, liquid fuels, and other valuable co-products from sustainably managed biomass resources. Greatly expanded reliance on biofuels will, however, require further progress in reducing production costs; minimizing land, water, and fertilizer use; and addressing potential impacts on biodiversity. Biofuels options based on the conversion of lignocellulose rather than starches appear more promising in terms of minimizing competition between growing food and producing energy and in terms of maximizing the environmental benefits associated with biomass-based transportation fuels.

It will be equally important to hasten the development and deployment of a less carbon-intensive mix of fossil fuel-based technologies. Natural gas, in particular, has a critical role to play as a bridge fuel in the transition to more sustainable energy systems. Assuring access to adequate supplies of this relatively clean resource and promoting the diffusion of efficient gas technologies in a variety of applications is therefore an important public policy priority for the near to medium term.

Simultaneously, great urgency must be given to developing and commercializing technologies that would allow for the continued use of coal—the world’s most abundant fossil-fuel resource—in a manner that does not pose intolerable environmental risks. Despite increased scientific certainty and growing concern about climate change, the construction of long-lived, conventional, coal-fired power plants has continued and even accelerated in recent years. The substantial expansion of coal capacity that is now underway around the world may pose the single greatest challenge to future efforts aimed at stabilizing carbon dioxide levels in the atmosphere. Managing the greenhouse gas ‘footprint’ of this existing capital stock, while making the transition to advanced conversion technologies that incorporate carbon capture and storage, thus represents a critical technological and economic challenge.

Nuclear technology could continue to contribute to future low-carbon energy supplies, provided significant concerns in terms of weapons proliferation, waste disposal, cost, and public safety (including vulnerability to acts of terrorism) can be—and are—addressed.



The Role of Government and the Contribution of Science and Technology

Because markets will not produce desired outcomes unless the right incentives and price signals are in place, governments have a vital role to play in creating the conditions necessary to promote optimal results and support long-term investments in new energy infrastructure, energy research and development, and high-risk/high-payoff technologies. Where the political will exists to create the conditions for a sustainable energy transition, a wide variety of policy instruments are available, from market incentives such as a price or cap on carbon emissions (which can be especially effective in influencing long-term capital investment decisions) to efficiency standards and building codes, which may be more effective than price signals in bringing about change on the end-use side of the equation. Longer term, important policy opportunities also exist at the level of city and land-use planning, including improved delivery systems for energy, water, and other services, as well as advanced mobility systems.

Science and technology (S&T) clearly have a major role to play in maximizing the potential and reducing the cost of existing energy options while also developing new technologies that will expand the menu of future options. To make good on this promise, the S&T community must have access to the resources needed to pursue already promising research areas and to explore more distant possibilities. Current worldwide investment in energy research and development is widely considered to be inadequate to the challenges at hand.

Accordingly, a substantial increase—on the order of at least a doubling of current expenditures—in the public and private resources directed to advancing critical energy technology priorities is needed. Cutting subsidies to established energy industries could provide some of the resources needed while simultaneously reducing incentives for excess consumption and other distortions that remain common to energy markets in many parts of the world. It will be necessary to ensure that public expenditures in the future are directed and applied more effectively, both to address well-defined priorities and targets for research and development in critical energy technologies and to pursue needed advances in basic science. At the same time, it will be important to enhance collaboration, cooperation, and coordination across institutions and national boundaries in the effort to deploy improved technologies.


The Case for Immediate Action

Overwhelming scientific evidence shows that current energy trends are unsustainable. Significant ecological, human health and development, and energy security needs require immediate action to effect change. Aggressive changes in policy are needed to accelerate the deployment of superior technologies. With a combination of such policies at the local, national, and international level, it should be possible—both technically and economically—to elevate the living conditions of most of humanity while simultaneously addressing the risks posed by climate change and other forms of energy-related environmental degradation and reducing the geopolitical tensions and economic vulnerabilities generated by existing patterns of dependence on predominantly fossil-fuel resources.

The Study Panel reached nine major conclusions, along with actionable recommendations. These conclusions and recommendations have been formulated within a holistic approach to the transition toward a sustainable energy future. This implies that not a single one of them can be successfully pursued without proper attention to the others. Prioritization of the recommendations is thus intrinsically difficult.  Nonetheless, the Study Panel believes that, given the dire prospect of climate change, the following three recommendations should be acted upon without delay and simultaneously:

    Concerted efforts should be mounted to improve energy efficiency and reduce the carbon intensity of the world economy, including the worldwide introduction of price signals for carbon emissions, with consideration of different economic and energy systems in individual countries.
    Technologies should be developed and deployed for capturing and sequestering carbon from fossil fuels, particularly coal.
    Development and deployment of renewable energy technologies should be accelerated in an environmentally responsible way.

Taking into account the three urgent recommendations above, another recommendation stands out by itself as a moral and social imperative and should be pursued with all means available:

    The poorest people on this planet should be supplied with basic, modern energy services.

Achieving a sustainable energy future requires the participation of all. But there is a division of labor in implementing the various recommendations of this report. The Study Panel has identified the following principal ‘actors’ that must take responsibility for achieving results:

    Multi-national organizations (e.g., United Nations, World Bank, regional development banks)
    Governments (national, regional, and local)
    S&T community (and academia)
    Private sector (businesses, industry, foundations)
    Nongovernmental organizations (NGOs)
    General public

Conclusions, recommendations, actions
Based on the key points developed in this report, the Study Panel offers these conclusions with recommendations and respective actions by the principal actors.


Conclusion 1

Meeting the basic energy needs of the poorest people on this planet is a moral and social imperative that can and must be pursued in concert with sustainability objectives. Today, an estimated 2.4 billion people use coal, charcoal, firewood, agricultural residues, or dung as their primary cooking fuel. Roughly 1.6 billion people worldwide live without electricity. Vast numbers of people, especially women and girls, are deprived of economic and educational opportunities without access to affordable, basic labor-saving devices or adequate lighting, added to the time each day spent gathering fuel and water. The indoor air pollution caused by traditional cooking fuels exposes millions of families to substantial health risks. Providing modern forms of energy to the world’s poor could generate multiple benefits, easing the day-to-day struggle to secure basic means of survival; reducing substantial pollution-related health risks; freeing up scarce capital and human resources; facilitating the delivery of essential services, including basic medical care; and mitigating local environmental degradation. Receiving increased international attention, these linkages were a major focus of the 2002 World Summit for Sustainable Development in Johannesburg, which recognized the importance of expanded access to reliable and affordable energy services as a prerequisite for achieving the United Nation’s Millennium Development Goals.


    Place priority on achieving much greater access of the world's poor to clean, affordable, high-quality fuels and electricity. The challenge of expanding access to modern forms of energy revolves primarily around issues of social equity and distribution—the fundamental problem is not one of inadequate global resources, unacceptable environmental damage, or unavailable technologies. Addressing the basic energy needs of the world’s poor is clearly central to the larger goal of sustainable development and must be a top priority for the international community if some dent is to be made in reducing current inequities.
    Formulate policy at all levels, from global to village scale, with greater awareness of the substantial inequalities in access to energy services that now exist, not only between countries but between populations within the same country and even between households within the same town or village. In many developing countries, a small elite uses energy in much the same way as in the industrialized world, while most of the rest of the population relies on traditional, often poor-quality and highly polluting forms of energy. In other developing countries, energy consumption by a growing middle class is contributing significantly to global energy demand growth and is substantially raising national per capita consumption rates, despite little change in the consumption patterns of the very poor. The reality that billions of people suffer from limited access to electricity and clean cooking fuels must not be lost in per capita statistics.


    Given the international dimension of the problem, multinational organizations like the United Nations and the World Bank should take the initiative to draw up a plan for eliminating the energy poverty of the world’s poor. As a first step, governments and NGOs can assist by supplying data on the extent of the problem in their countries.
    The private sector and the S&T community can help promote the transfer of appropriate technologies. The private sector can, in addition, help by making appropriate investments.
    The media should make the general public aware of the enormity of the problem.



Conclusion 2

Concerted efforts must be made to improve energy efficiency and reduce the carbon intensity of the world economy.Economic competitiveness, energy security, and environmental considerations all argue for pursuing cost-effective, end-use efficiency opportunities. Such opportunities may be found throughout industry, transportation, and the built environment. To maximize efficiency gains and minimize costs, improvements should be incorporated in a holistic manner and from the ground up wherever possible, especially where long-lived infrastructure is involved. At the same time, it will be important to avoid underestimating the difficulty of achieving nominal energy efficiency gains, as frequently happens when analyses assume that reduced energy use is an end in itself rather than an objective regularly traded against other desired attributes.


    Promote the enhanced dissemination of technology improvement and innovation between industrialized and developing countries. It will be especially important for all nations to work together to ensure that developing countries adopt cleaner and more efficient technologies as they industrialize.
    Align economic incentives—especially for durable capital investments—with long-run sustainability objectives and cost considerations. Incentives for regulated energy service providers should be structured to encourage co-investment in cost-effective efficiency improvements, and profits should be delinked from energy sales.
    Adopt policies aimed at accelerating the worldwide rate of decline in the carbon intensity of the global economy, where carbon intensity is measured as carbon dioxide equivalent emissions divided by gross world product, a crude measure of global well-being. Specifically, the Study Panel recommends immediate policy action to introduce meaningful price signals for avoided greenhouse gas emissions. Less important than the initial prices is that clear expectations be established concerning a predictable escalation of those prices over time. Merely holding carbon dioxide emissions constant over the next several decades implies that the carbon intensity of the world economy needs to decline at roughly the same rate as gross world product grows—achieving the absolute reductions in global emissions needed to stabilize atmospheric concentrations of greenhouse gases will require the worldwide rate of decline in carbon intensity to begin outpacing worldwide economic growth.
    Enlist cities as a major driving force for the rapid implementation of practical steps to improve energy efficiency.
    Inform consumers about the energy-use characteristics of products through labeling and implement mandatory minimum efficiency standards for appliances and equipment. Standards should be regularly updated and must be effectively enforced.


    Governments, in a dialogue with the private sector and the S&T community, should develop and implement (further) policies and regulations aimed at achieving greater energy efficiency and lower energy intensity for a great variety of processes, services, and products.
    The general public must be made aware, by governments, the media, and NGOs of the meaning and necessity of such policies and regulations.
    The S&T community should step up its efforts to research and develop new, low-energy technologies.
    Governments, united in intergovernmental organizations, should agree on realistic price signals for carbon emissions—recognizing that the economies and energy systems of different countries will result in different individual strategies and trajectories—and make these price signals key components of further actions on reducing the carbon emissions.
    The private sector and the general public should insist that governments issue clear carbon price signals.
Conclusion 3

CONCLUSION 3. Technologies for capturing and sequestering carbon from fossil fuels, particularly coal, can play a major role in the cost-effective management of global carbon dioxide emissions.  As the world’s most abundant fossil fuel, coal will continue to play a large role in the world’s energy mix. It is also the most carbon-intensive conventional fuel in use, generating almost twice as much carbon dioxide per unit of energy supplied than natural gas. Today, new coal-fired power plants—most of which can be expected to last more than half a century—are being constructed at an unprecedented rate. Moreover, the carbon contribution from coal could expand further if nations with large coal reserves like the United States, China, and India turn to coal to address energy security concerns and develop alternatives to petroleum.


    Accelerate the development and deployment of advanced coal technologies. Without policy interventions the vast majority of the coal-fired power plants constructed in the next two decades will be conventional, pulverized coal plants. Present technologies for capturing carbon dioxide emissions from pulverized coal plants on a retrofit basis are expensive and energy intensive. Where new coal plants without capture must be constructed, the most efficient technologies should be used. In addition, priority should be given to minimize the costs of future retrofits for carbon capture by developing at least some elements of carbon capture technology at every new plant. Active efforts to develop such technologies for different types of base plants are currently underway and should be encouraged by promoting the construction of full-scale plants that utilize the latest technology advances.
    Aggressively pursue efforts to commercialize carbon capture and storage. Moving forward with full-scale demonstration projects is critical, as is continued study and experimentation to reduce costs, improve reliability, and address concerns about leakage, public safety, and other issues. For capture and sequestration to be widely implemented, it will be necessary to develop regulations and to introduce price signals for carbon emissions. Based on current cost estimates, the Study Panel believes price signals on the order of US$100–150 per avoided metric ton of carbon equivalent (US$27–41 per ton of carbon dioxide equivalent) will be required to induce the widespread adoption of carbon capture and storage. Price signals at this level would also give impetus to the accelerated deployment of biomass and other renewable energy technologies.
    Explore potential retrofit technologies for post-combustion carbon capture suitable for the large and rapidly growing population of existing pulverized coal plants. In the near term, efficiency improvements and advanced pollution control technologies should be applied to existing coal plants as a means of mitigating their immediate climate change and public health impacts.
    Pursue carbon capture and storage with systems that co-fire coal and biomass. This technology combination provides an opportunity to achieve net negative greenhouse gas emissions—effectively removing carbon dioxide from the atmosphere.


    The private sector and the S&T community should join forces to further investigate the possibilities for carbon capture and sequestration and develop adequate technologies for demonstration.
    Governments should facilitate the development of these technologies by making available funds and opportunities (such as test sites).
    The general public needs to be thoroughly informed about the advantages of carbon sequestration and about the relative manageability of associated risks. The media can assist with this.
Conclusion 4

Competition for oil and natural gas supplies has the potential to become a source of growing geopolitical tension and economic vulnerability for many nations in the decades ahead. In many developing countries, expenditures for energy imports also divert scarce resources from other urgent public health, education, and infrastructure development needs. The transport sector accounts for just 25 percent of primary energy consumption worldwide, but the lack of fuel diversity in this sector makes transport fuels especially valuable.


    Introduce policies and regulations that promote reduced energy consumption in the transport sector by (a) improving the energy efficiency of automobiles and other modes of transport and (b) improving the efficiency of transport systems (e.g., through investments in mass transit, better land-use and city planning, etc.).
    Develop alternatives to petroleum to meet the energy needs of the transport sector, including biomass fuels, plug-in hybrids, and compressed natural gas, as well as—in the longer run— advanced alternatives, such as hydrogen fuel cells.
    Implement policies to ensure that the development of petroleum alternatives is pursued in a manner that is compatible with other sustainability objectives. Current methods for liquefying coal and extracting oil from unconventional sources, such as tar sands and shale oil, generate substantially higher levels of carbon dioxide and other pollutant emissions compared to conventional petroleum consumption. Even with carbon capture and sequestration, a liquid fuel derived from coal will at best produce emissions of carbon dioxide roughly equivalent to those of conventional petroleum at the point of combustion. If carbon emissions from the conversion process are not captured and stored, total fuel-cycle emissions for this energy pathway as much as double. The conversion of natural gas to liquids is less carbon intensive than coal to liquids, but biomass remains the only near-term feedstock that has the potential to be truly carbon-neutral and sustainable on a long-term basis. In all cases, full fuel-cycle impacts depend critically on the feedstock being used and on the specific extraction or conversion methods being employed.


    Governments should introduce (further) policies and regulations aimed at reducing energy consumption and developing petroleum alternatives for use in the transport sector.
    The private sector and the S&T community should continue developing technologies adequate to that end.
    The general public’s awareness of sustainability issues related to transportation energy use should be significantly increased. The media can play an important role in this effort.
Conclusion 5

As a low-carbon resource, nuclear power can continue to make a significant contribution to the world’s energy portfolio in the future, but only if major concerns related to capital cost, safety, and weapons proliferation are addressed. Nuclear power plants generate no carbon dioxide or conventional air pollutant emissions during operation, use a relatively abundant fuel feedstock, and involve orders-of-magnitude smaller mass flows, relative to fossil fuels. Nuclear’s potential, however, is currently limited by concerns related to cost, waste management, proliferation risks, and plant safety (including concerns about vulnerability to acts of terrorism and concerns about the impact of neutron damage on plant materials in the case of life extensions). A sustained role for nuclear power will require addressing these hurdles.


    Replace the current fleet of aging reactors with plants that incorporate improved intrinsic (passive) safety features.
    Address cost issues by pursuing the development of standardized reactor designs.
    Understand the impact of long-term aging on nuclear reactor systems (e.g., neutron damage to materials) and provide for the safe and economic decommissioning of existing plants.
    Develop safe, retrievable waste management solutions based on dry cask storage as longer-term disposal options are explored. While long-term disposal in stable geological repositories is technically feasible, finding socially acceptable pathways to implement this solution remains a significant challenge.
    Address the risk that civilian nuclear materials and knowledge will be diverted to weapons applications (a) through continued research on proliferation-resistant uranium enrichment and fuel-recycling capability and on safe, fast neutron reactors that can burn down waste generated from thermal neutron reactors and (b) through efforts to remedy shortcomings in existing international frameworks and governance mechanisms.
    Undertake a transparent and objective re-examination of the issues surrounding nuclear power and their potential solutions. The results of such a reexamination should be used to educate the public and policymakers.


    Given the controversy over the future of nuclear power worldwide, the United Nations should commission—as soon as possible—a transparent and objective re-examination of the issues that surround nuclear power and their potential solutions. It is essential that the general public be informed about the outcome of this re-examination.
    The private sector and the S&T community should continue research and development efforts targeted at improving reactor safety and developing safe waste management solutions.
    Governments should facilitate the replacement of the current fleet of aging reactors with modern, safer plants. Governments and intergovernmental organizations should enhance their efforts to remedy shortcomings in existing international frameworks and governance mechanisms.
Conclusion 6

Renewable energy in its many forms offers immense opportunities for technological progress and innovation.

Over the next 30–60 years, sustained efforts must be directed toward realizing these opportunities as part of a comprehensive strategy that supports a diversity of resource options over the next century. The fundamental challenge for most renewable options involves cost-effectively tapping inherently diffuse and in some cases intermittent resources. Sustained, long-term support—in various forms—is needed to overcome these hurdles. Renewable energy development can provide important benefits in underdeveloped and developing countries because oil, gas, and other fuels are hard cash commodities.


    Implement policies—including policies that generate price signals for avoided carbon emissions—to ensure that the environmental benefits of renewable resources relative to non-renewable resources will be systematically recognized in the marketplace.
    Provide subsidies and other forms of public support for the early deployment of new renewable technologies. Subsidies should be targeted to promising but not-yet-commercial technologies and decline gradually over time.
    Explore alternate policy mechanisms to nurture renewable energy technologies, such as renewable portfolio standards (which set specific goals for renewable energy deployment) and ‘reverse auctions’ (in which renewable energy developers bid for a share of limited public funds on the basis of the minimum subsidy they require on a per kilowatt-hour basis).
    Invest in research and development on more transformational technologies, such as new classes of solar cells that can be made with thin-film, continuous fabrication processes. (See also biofuels recommendations #7.)
    Conduct sustained research to assess and mitigate any negative environmental impacts associated with the large-scale deployment of renewable energy technologies. Although these technologies offer many environmental benefits, they may also pose new environmental risks as a result of their low power density and the consequently large land area required for large-scale deployment.


    Governments should substantially facilitate the use—in an environmentally sustainable way—of renewable energy resources through adequate policies and subsidies. A major policy step in this direction would include implementing clear price signals for avoided greenhouse gas emissions.
    Governments should also promote research and development in renewable energy technologies by supplying significantly more public funding.
    The private sector, aided by government subsidies, should seek entrepreneurial opportunities in the growing renewable energy market.
    The S&T community should devote more attention to overcoming the cost and technology barriers that currently limit the contribution of renewable energy sources.
    NGOs can assist in promoting the use of renewable energy sources in developing countries.
    The media can play an essential role in heightening the general public’s awareness of issues related to renewable energy.
Conclusion 7

Biofuels hold great promise for simultaneously addressing climate-change and energy-security concerns.

Improvements in agriculture will allow for food production adequate to support a predicted peak world population on the order of 9 billion people with excess capacity for growing energy crops. Maximizing the potential contribution of biofuels requires commercializing methods for producing fuels from lignocellulosic feedstocks (including agricultural residues and wastes), which have the potential to generate five to ten times more fuel than processes that use starches from feedstocks, such as sugar cane and corn. Recent advances in molecular and systems biology show great promise in developing improved feedstocks and much less energy-intensive means of converting plant material into liquid fuel. In addition, intrinsically more efficient conversion of sunlight, water, and nutrients into chemical energy may be possible with microbes.


    Conduct intensive research into the production of biofuels based on lignocellulose conversion.
    Invest in research and development on direct microbial production of butanol or other forms of biofuels that may be superior to ethanol.
    Implement strict regulations to insure that the cultivation of biofuels feedstocks accords with sustainable agricultural practices and promotes biodiversity, habitat protection, and other land management objectives.
    Develop advanced bio-refineries that use biomass feedstocks to self-generate power and extract higher-value co-products. Such refineries have the potential to maximize economic and environmental gains from the use of biomass resources.
    Develop improved biofuels feedstocks through genetic selection and/or molecular engineering, including drought resistant and self-fertilizing plants that require minimal tillage and fertilizer or chemical inputs.
    Mount a concerted effort to collect and analyze data on current uses of biomass by type and technology (both direct and for conversion to other fuels), including traditional uses of biomass.
    Conduct sustained research to assess and mitigate any adverse environmental or ecosystem impacts associated with the large-scale cultivation of biomass energy feedstocks, including impacts related to competition with other land uses (including uses for habitat preservation and food production), water needs, etc.


    The S&T community and the private sector should greatly augment their research and development (and deployment) efforts toward more efficient, environmentally sustainable technologies and processes for the production of modern biofuels.
    Governments can help by stepping up public research and development funding and by adapting existing subsidy and fiscal policies so as to favor the use of biofuels over that of fossil fuels, especially in the transport sector.
    Governments should pay appropriate attention to promoting sustainable means of biofuels production and to avoiding conflicts between biofuel production and food production.
Conclusion 8 

The development of cost-effective energy storage technologies, new energy carriers, and improved transmission infrastructure could substantially reduce costs and expand the contribution from a variety of energy supply options.

Such technology improvements and infrastructure investments are particularly important to tap the full potential of intermittent renewable resources, especially in cases where some of the most abundant and cost-effective resource opportunities exist far from load centers. Improved storage technologies, new energy carriers, and enhanced transmission and distribution infrastructure will also facilitate the delivery of modern energy services to the world’s poor—especially in rural areas.


    Continue long-term research and development into potential new energy carriers for the future, such as hydrogen. Hydrogen can be directly combusted or used to power a fuel cell and has a variety of potential applications, including as an energy source for generating electricity or in other stationary applications and as an alternative to petroleum fuels for aviation and road transport. Cost and infrastructure constraints, however, are likely to delay widespread commercial viability until mid-century or later.
    Develop improved energy storage technologies, either physical (e.g., compressed air or elevated water storage) or chemical (e.g., batteries, hydrogen, or hydrocarbon fuel produced from the reduction of carbon dioxide) that could significantly improve the market prospects of intermittent renewable resources, such as wind and solar power.
    Pursue continued improvements and cost reductions in technologies for transmitting electricity over long distances. High-voltage, direct-current transmission lines, in particular, could be decisive in making remote areas accessible for renewable energy development, improving grid reliability, and maximizing the contribution from a variety of low-carbon electricity sources. In addition, it will be important to improve overall grid management and performance through the development and application of advanced or ‘smart’ grid technologies that could greatly enhance the responsiveness and reliability of electricity transmission and distribution networks.


    The S&T community, together with the private sector, should have focus on research and development in this area.
    Governments can assist by increasing public funding for research and development and by facilitating needed infrastructure investments.
Conclusion 9

The S&T community—together with the general public—has a critical role to play in advancing sustainable energy solutions and must be effectively engaged.

As noted repeatedly in the foregoing recommendations, the energy challenges of this century and beyond demand sustained progress in developing, demonstrating, and deploying new and improved energy technologies. These advances will need to come from the S&T community, motivated and supported by appropriate policies, incentives, and market drivers.


    Provide increased funding for public investments in sustainable energy research and development, along with incentives and market signals to promote increased private-sector investments.
    Effect greater coordination of technology efforts internationally, along with efforts to focus universities and research institutions on the sustainability challenge.
    Conduct rigorous analysis and scenario development to identify possible combinations of energy resources and end-use and supply technologies that have the potential to simultaneously address the multiple sustainability challenges linked to energy.
    Stimulate efforts to identify and assess specific changes in institutions, regulations, market incentives, and policy that would most effectively advance sustainable energy solutions.
    Create an increased focus on specifically energy-relevant awareness, education, and training across all professional fields with a role to play in the sustainable energy transition.
    Initiate concerted efforts to inform and educate the public about important aspects of the sustainable energy challenge, such as the connection between current patterns of energy production and use and critical environmental and security risks.

    Begin enhanced data collection efforts to support better decision-making in important policy areas that are currently characterized by a lack of reliable information (large cities in many developing countries, for example, lack the basic data needed to plan effectively for transportation needs).


    The S&T community must strive for better international coordination of energy research and development efforts, partly in collaboration with the private sector. It should seek to articulate a focused, collaborative agenda aimed at addressing key obstacles to a sustainable energy future.

    Governments (and intergovernmental organizations) must make more public funding available to not only boost the existing contribution from the S&T community but also to attract more scientists and engineers to working on sustainable energy problems.

    The why and how of energy research and development should be made transparent to the general public to build support for the significant and sustained investments that will be needed to address long-term sustainability needs.

    The S&T community itself, intergovernmental organizations, governments, NGOs, the media, and—to a lesser extent—the private sector should be actively engaged in educating the public about the need for these investments.


Lighting the Way

While the current energy outlook is very sobering, the Study Panel believes that there are sustainable solutions to the energy problem. Aggressive support of energy science and technology must be coupled with incentives that accelerate the concurrent development and deployment of innovative solutions that can transform the entire landscape of energy demand and supply. Opportunities to substitute superior supply-side and end-use technologies exist throughout the world’s energy systems, but current investment flows generally do not reflect these opportunities.

Science and engineering provide guiding principles for the sustainability agenda. Science provides the basis for a rational discourse about trade-offs and risks, for selecting research and development priorities, and for identifying new opportunities—openness is one of its dominant values. Engineering, through the relentless optimization of the most promising technologies, can deliver solutions—learning by doing is among its dominant values. Better results will be achieved if many avenues are explored in parallel, if outcomes are evaluated with actual performance measures, if results are reported widely and fully, and if strategies are open to revision and adaptation.

Long-term energy research and development is thus an essential component of the pursuit of sustainability. Significant progress can be achieved with existing technology but the scale of the long-term challenge will demand new solutions. The research community must have the means to pursue promising technology pathways that are already in view and some that may still be over the horizon.

The transition to sustainable energy systems also requires that market incentives be aligned with sustainability objectives. In particular, robust price signals for avoided carbon emissions are critical to spur the development and deployment of low-carbon energy technologies. Such price signals can be phased in gradually, but expectations about how they will change over time must be established in advance and communicated clearly so that businesses can plan with confidence and optimize their long-term capital investments.

Critical to the success of all the tasks ahead are the abilities of individuals and institutions to effect changes in energy resources and usage. Capacity building, both in terms of investments in individual expertise and institutional effectiveness, must become an urgent priority of all principal actors: multi-national organizations, governments, corporations, educational institutions, non-profit organizations, and the media. Above all, the general public must be provided with sound information about the choices ahead and the actions required for achieving a sustainable energy future.


 1. The Sustainable Energy Challenge

Humankind has faced daunting problems in every age, but today’s generation confronts a unique set of challenges. The environmental systems on which all life depends are being threatened locally, regionally, and at a planetary level by human actions. And even as great numbers of people enjoy unprecedented levels of material prosperity, a greater number remains mired in chronic poverty, without access to the most basic of modern services and amenities and with minimal opportunities for social (e.g., educational) and economic advancement. At the same time, instability and conflict in many parts of the world have created profound new security risks.

Energy is critical to human development and connects in fundamental ways to all of these challenges. As a result, the transition to sustainable energy resources and systems provides an opportunity to address multiple environmental, economic, and development needs. From an environmental perspective, it is becoming increasingly clear that humanity’s current energy habits must change to reduce significant public health risks, avoid placing intolerable stresses on critical natural systems, and, in particular, to manage the substantial risks posed by global climate change. By spurring the development of alternatives to today’s conventional fuels, a sustainable energy transition could also help to address the energy security concerns that are again at the forefront of many nations’ domestic and foreign policy agendas, thereby reducing the likelihood that competition for finite and unevenly distributed oil and gas resources will fuel growing geopolitical tensions in the decades ahead. Finally, increased access to clean, affordable, high-quality fuels and electricity could generate multiple benefits for the world’s poor, easing the day-to-day struggle to secure basic means of survival; enhancing educational opportunities; reducing substantial pollution-related health risks; freeing up scarce capital and human resources; facilitating the delivery of essential services, including basic medical care; and mitigating local environmental degradation.

Energy, in short, is central to the challenge of sustainability in all its dimensions: social, economic, and environmental. To this generation falls the task of charting a new course. Now and in the decades ahead no policy objective is more urgent than that of finding ways to produce and use energy that limit environmental degradation, preserve the integrity of underlying natural systems, and support rather than undermine progress toward a more stable, peaceful, equitable, and humane world. Many of the insights, knowledge, and tools needed to accomplish this transition already exist but more will almost certainly be needed. At bottom the decisive question comes down to this: Can we humans collectively grasp the magnitude of the problem and muster the leadership, endurance, and will to get the job done?


 1.1 The scope of the challenge

Linkages between energy use and environmental quality have always been apparent, from the deforestation caused by fuelwood use even in early societies to the high levels of local air and water pollution that have commonly accompanied the early phases of industrialization. In recent decades, advances in scientific understanding and in monitoring and measurement capabilities have brought increased awareness of the more subtle environmental and human-health effects associated with energy production, conversion, and use. Fossil-fuel combustion is now known to be responsible for substantial emissions of air pollutants—including sulfur, nitrogen oxides, hydrocarbons, and soot—that play a major role in the formation of fine particulate matter, ground-level ozone, and acid rain; energy use is also a major contributor to the release of long-lived heavy metals, such as lead and mercury, and other hazardous materials into the environment. Energy-related air pollution (including poor indoor air quality from the use of solid fuels for cooking and heating) not only creates substantial public health risks, especially where emission controls are limited or nonexistent, it harms ecosystems, degrades materials and structures, and impairs agricultural productivity. In addition, the extraction, transport, and processing of primary energy sources such as coal, oil, and uranium are associated with a variety of damages or risks to land, water, and ecosystems while the wastes generated by some fuel cycles—notably nuclear electricity production—present additional disposal issues.

Although the most obvious environmental impacts from energy production and use have always been local, significant impacts—including the long-range transport of certain pollutants in the atmosphere—are now known to occur on regional, continental, and even transcontinental scales. And at a global level, climate change is emerging as the most consequential and most difficult energy-environment linkage of all. The production and use of energy contributes more than any other human activity to the change in radiative forcing that is currently occurring in the atmosphere; in fact, fossil-fuel combustion alone currently accounts for well over half of total greenhouse gas emissions worldwide (after accounting for different gases’ carbon dioxide equivalent warming potential). Since the dawn of the industrial era, carbon dioxide levels in the atmosphere have increased by about 40 percent; going forward, trends in energy production, conversion, and use—more than any other factor within human control—are likely to determine how quickly those levels continue to rise, and how far. The precise implications of the current trajectory remain unknown, but there is less and less doubt that the risks are large and more and more evidence that human-induced global warming is already underway. In its recent, Fourth Assessment report, for example, the Intergovernmental Panel on Climate Change (IPCC) concluded that evidence for the warming of the Earth’s climate system was now ‘unequivocal’ and identified a number of potential adverse impacts associated with continued warming, including increased risks to coasts, ecosystems, fresh-water resources, and human health (IPCC, 2007a: p. 5; and 2007b) . In this context, making the transition to lower-carbon energy options is widely acknowledged as a central imperative in the effort to reduce climate-change risks.

Another issue that will continue to dominate regional, national, and international energy policy debates over the next several decades is energy security. Defined as access to adequate supplies of energy when needed, in the form needed, and at affordable prices, energy security remains a central priority for all nations concerned with promoting healthy economic growth and maintaining internal as well as external stability. In the near to medium term, energy security concerns are almost certain to focus on oil and, to a lesser extent, on natural gas. As demand for these resources grows and as reserves of relatively cheap and readily accessible supplies decline in many parts of the world, the potential for supply disruptions, trade conflicts, and price shocks is likely to increase. Already, there is concern that the current environment of tight supplies and high and volatile prices is exacerbating trade imbalances, slowing global economic growth, and directly or indirectly complicating efforts to promote international peace and security. The problem is particularly acute for many developing countries that devote a large fraction of their foreign exchange earnings to oil imports, thus reducing the resources available to support investments needed for economic growth and social development.

Box 1.1 Energy and the Millennium Development Goals

Energy services can play a variety of direct and indirect roles in helping to achieve the Millennium Development Goals:

To halve extreme poverty. Access to energy services facilitates economic development – micro-enterprise, livelihood activities beyond daylight hours, locally owned businesses, which will create employment – and assists in bridging the ‘digital divide. ’

To reduce hunger and improve access to safe drinking water. Energy services can improve access to pumped drinking water and provide fuel for cooking the 95 percent of staple foods that need cooking before they can be eaten.

To reduce child and maternal mortality; and to reduce diseases. Energy is a key component of a functioning health system, contributing, for example, to lighting operating theatres, refrigerating vaccines and other medicines, sterilizing equipment, and providing transport to health clinics.

To achieve universal primary education, and to promote gender equality and empowerment of women. Energy services reduce the time spent by women and children (especially girls) on basic survival activities (gathering firewood, fetching water, cooking, etc.); lighting permits home study, increases security, and enables the use of educational media and communications in schools, including information and communication technologies.

To ensure environmental sustainability. Improved energy efficiency and use of cleaner alternatives can help to achieve sustainable use of natural resources, as well as reduce emissions, which protects the local and global environment.

Providing the energy services needed to sustain economic growth and, conversely, avoiding a situation where lack of access to such services constrains growth and development, remains a central policy objective for all nations, and an especially important challenge for developing nations given the substantial resource and capital investments that will be required. Within that larger context, a third important set of issues (in addition to the environmental and energy-security issues noted above) concerns the specific linkages between access to energy services, poverty alleviation, and human development. These linkages have recently drawn increased international attention and were a major focus of the 2002 World Summit for Sustainable Development in Johannesburg, which recognized the importance of expanded access to reliable and affordable energy services as a prerequisite for achieving the United Nation’s Millennium Development Goals. These linkages are discussed in detail in other reports (notably in the 2000 and 2004 World Energy Assessments undertaken by the United Nations Development Programme, United Nations Department of Economic and Social Affairs, and World Energy Council) and summarized in Box 1.1 (DFID, 2002).

In brief, substantial inequalities in access to energy services now exist, not only between countries but between populations within the same country and even between households within the same town or village. In many developing countries, a small elite uses energy in much the same way as in the industrialized world, while most of the rest of the population relies on traditional, often poor-quality and highly polluting forms of energy. It is estimated that today roughly 2.4 billion people use charcoal, firewood, agricultural residues, or dung as their primary cooking fuel, while some 1.6 billion people worldwide live without electricity. Without access to affordable, basic labor-saving devices or adequate lighting and compelled to spend hours each day gathering fuel and water, vast numbers of people, especially women and girls, are deprived of economic and educational opportunities; in addition, millions are exposed to substantial health risks from indoor air pollution caused by traditional cooking fuels. The challenge of expanding access to energy services revolves primarily around issues of social equity and distribution—the fundamental problem is not one of inadequate global resources or of a lack of available technologies. Addressing the basic energy needs of the world’s poor is clearly central to the larger goal of sustainable development and must be a top priority for developing countries in the years ahead if some dent is to be made in reducing current inequities.

 1.2 The scale of the challenge

The scale of the sustainable energy challenge is illustrated by a quick review of current consumption patterns and of the historic linkages between energy use, population, and economic growth. Human development to the end of the 18th century was marked by only modest rates of growth in population, per capita income, and energy use. As the Industrial Revolution gathered pace, this began to change. Over the last century alone, world population grew 3.8 times, from 1.6 to 6.1 billion people; worldwide average per capita income increased nine-fold (to around US$8,000 per person in 2000) ; annual primary energy use rose by a similar amount (ten-fold) to 430 exajoules (EJ); and fossil-fuel use alone increased twenty-fold.

Throughout this period, energy use in many countries followed a common pattern. As societies began to modernize and shift from traditional forms of energy (such as wood, crop residues, and dung) to commercial forms of energy (liquid or gaseous fuels and electricity), their energy consumption per capita and per unit of economic output (gross domestic product) often grew rapidly. At a later stage of development, however, further growth in energy consumption typically slowed as the market for energy-using devices reached a point of saturation and as wealthier economies shifted away from more energy-intensive manufacturing and toward a greater role for the less energy-intensive service sector. The rate of growth in energy consumption also diminished in some industrialized countries as a result of concerted energy efficiency and conservation programs that were launched in the wake of sharp oil price increases in the early 1970s. Figure 1.1 shows declining energy intensity trends for OECD and non-OECD countries over the last 18 years.

In recent years, the energy intensity of the world’s industrialized economies has been declining at an average annual rate of 1.1 percent per year, while the energy intensity of the non-OECD economies has been declining, on average, even faster (presumably because these economies start from a base of higher intensity and lower efficiency). Because the rate of decline in energy intensity has generally not been sufficient to offset GDP growth, total energy consumption has continued to grow in industrialized countries and is growing even faster in many developing countries.














Figure 1.1 Energy intensity versus time, 1985-2005
TPES is total primary energy supply; GDP is gross domestic product; PPP is purchasing power parity; toe is ton oil equivalent.
Source: IEA, 2005

Looking ahead, current projections suggest that the world’s population will grow by another 50 percent over the first half of this century (to approximately 9 billion by 2050), world income will roughly quadruple, and energy consumption will either double or triple, depending on the pace of future reductions in energy intensity. But projections are notoriously unreliable: patterns of development, structural economic shifts, population growth, and lifestyle choices will all have a profound impact on future trends. As discussed later in this report, even small changes in average year-to-year growth or in the rate of intensity reductions can produce very different energy and emissions outcomes over the course of several decades. Simply boosting the historical rate of decline in energy intensity from 1 percent per year to 2 percent per year on a global average basis, for example, would reduce energy demand in 2030 by 26 percent below the business-as-usual base case. Numerous engineering analyses suggest that intensity reductions of this magnitude could be achieved by concerted investments in energy efficiency over the next half century, but even seemingly modest changes in annual average rates of improvement can be difficult to sustain in practice, especially over long periods of time, and may require significant policy commitments.

Confronted with the near certainty of continued growth in overall energy demand, even with concerted efforts to further improve efficiency, reduce energy intensity, and promote a more equitable distribution of resources, the scale of the sustainability challenge becomes more daunting still when one considers the current mix of resources used to meet human energy needs. Figure 1.2 shows total primary energy consumption for the OECD countries, developing countries, and transition economies (where the latter category chiefly includes Eastern European countries and the former Soviet Union), while Figures 1.3 and 1.4 show global primary energy consumption and global electricity production, broken down by fuel source.

Non-renewable, carbon-emitting fossil fuels (coal, oil, and natural gas) account for approximately 80 percent of world primary energy consumption (Figure 1.3). Traditional biomass comprises the next largest share (10 percent) while nuclear, hydropower, and other renewable resources (including modern biomass, wind, and solar power), respectively, account for 6, 2, and 1 percent of the total. Figure 1.4 shows the mix of fuels used to generate electricity worldwide. Again, fossil fuels—primarily coal and











Figure 1.2 Regional shares in world primary energy demand, including business-as-usual projections
1 megaton oil equivalent(Mtoe) equals 41.9 petajoules.
Source: IEA, 2006

natural gas—dominate the resource mix, accounting for two-thirds of global electricity production. The nuclear and hydropower contributions are roughly equal at 16 percent of the total, while non-hydro renewables account for approximately 2 percent of global production.

Most projections indicate that fossil fuels will continue to dominate the world’s energy mix for decades to come, with overall demand for these fuels and resulting carbon emissions rising accordingly.

Table 1.1 shows a reference case projection for future energy demand developed by the International Energy Agency (IEA) based largely on business-as-usual assumptions. It must be emphasized that these projections










Figure 1.3 World primary energy consumption by fuel, 2004
Note: Total world primary energy consumption in 2004 was 11,204 megatons oil equivalent (or 448 exajoules).
Source: IEA, 2006












Figure 1.4 World electricity production by energy source, 2004
Note: Total world electricity production in 2004 was 17,408 terawatt-hours (or 63 exajoules).
Source: IEA, 2006.









Note: 1 million ton oil equivalent equals 41.9 petajoules.
Source: IEA 2006

do not incorporate sustainability constraints (such as mitigation measures that might be necessary to manage climate risks)—as such, they are not intended to portray an inevitable future, much less a desirable one. Rather the usefulness of such projections lies in their ability to illuminate the consequences of allowing current trends to continue. For example, IEA’s reference case projections assume moderate growth in the use of renewable energy technologies. But since non-hydro renewables accounted for only 2 percent of world electricity production in 2004, fossil-fuel consumption and global carbon emissions continue to grow strongly by 2030. Indeed current forecasts suggest that a continuation of business-as-usual trends will produce a roughly 55 percent increase in carbon dioxide emissions over the next two decades.

The implications of these projections, from a climate perspective alone, are sobering. If the trends projected by IEA for the next quarter century continue beyond 2030, the concentration of carbon dioxide in the atmosphere would be on track to reach 540–970 parts per million by 2100—anywhere from two to three times the pre-industrial concentration of 280 parts per million. By contrast, it is increasingly evident that the responsible mitigation of climate-change risks will require significant reductions in global greenhouse gas emissions by mid-century. As part of its Fourth Assessment Report, the IPCC has identified numerous adverse impacts on water supplies, ecosystems, agriculture, coasts, and public health that would be predicted (with ‘high’ or ‘very high’ confidence) to accompany continued warming. Moreover, the current IPCC assessment places the onset for several of these ‘key impacts’ at a global mean temperature change of 2–3 degrees Celsius (IPCC, 2007a: p 13). The IPCC further estimates that limiting global warming to a 2–3 degrees Celsius change will require stabilizing atmospheric concentrations of greenhouse gases somewhere in the range of 450–550 parts per million in carbon dioxide equivalent terms. Based on numerous IPCC-developed scenarios, achieving stabilization within this range could require absolute reductions in global emissions of as much as 30–85 percent compared to 2000 levels by mid-century (IPCC 2007b: p 23-5). Hence, a major goal of this report is to offer recommendations for shifting the world’s current energy trajectory through the accelerated deployment of more efficient technologies and sustainable, low-carbon energy sources.

The consequences of current trends are also troubling, however, from an energy security perspective given the longer-term outlook for conventional oil supplies and given the energy expenditures and environmental impacts it implies, for countries struggling to meet basic social and economic-development needs. Recent forecasts suggest that a continuation of business-as-usual trends will produce a nearly 40 percent increase in world oil consumption by 2030, at a time when many experts predict that production of readily accessible, relatively cheap conventional oil will be rapidly approaching (or may have already reached) its peak. Moreover, IEA reference case projections, though they anticipate a substantial increase in energy consumption by developing countries, assume only modest progress over the next several decades toward reducing the large energy inequities that now characterize different parts of the world. This is perhaps not surprising insofar as the IEA projections are based on extrapolating past trends into the future; as such they do not account for the possibility that developing countries might follow a different trajectory than industrialized countries.


 1.3 The need for holistic approaches

Beyond the scope and scale of the issues involved, the challenge of moving to sustainable energy systems is complicated by several additional factors. First is the fact that different policy objectives can be in tension (or even at odds), especially if approached in isolation. For example, efforts to improve energy security—if they led to a massive expansion of coal use without concurrent carbon sequestration—could significantly exacerbate climate risks. Similarly, emulating historic patterns of industrialization in developing countries could, in a 21st century context, create substantial environmental and energy-security liabilities. Achieving sustainability almost certainly requires a holistic approach in which development needs, social inequities, environmental limits, and energy security are addressed—even if they cannot always be resolved at the same time. Priorities should be set, by region and by country.

Extending basic energy services to the billions of people who now lack access to electricity and clean cooking fuels, for example, could be accomplished in ways that would have only minimal impact on current levels of petroleum consumption and carbon dioxide emissions. Indeed, closer examination of the relationship between energy consumption and human well-being suggests that a more equitable distribution of access to energy services is entirely compatible with accelerated progress toward addressing energy-security and climate-change risks. Figure 1.6 compares per capita consumption of electricity in different countries in terms of their Human Development Index (HDI) — a composite measure of wellbeing that takes into account life expectancy, education, and GDP. The figure indicates that while a certain minimum level of electricity services is required to support human development, further consumption above that threshold is not necessarily linked to a higher HDI. Put another way, the figure indicates that a relatively high HDI (0.8 and above) has been achieved in countries where per capita levels of electricity consumption differ by as much as six-fold.

Box 1.2 A focus on cooking in the developing world

Clean, efficient stoves represent a major opportunity to extend energy and public health benefits to the billions of people who rely on traditional fuels for their household cooking needs.

Household energy ladder. Over 2.4 billion people in developing countries still rely on solid biomass fuels for their cooking needs. This number increases to 3 billion when the use of various types of coal for cooking is included. In fact, the use of solid biomass fuels for cooking accounts for as much as 30–90 percent of primary energy consumption in some developing countries. As incomes rise, people generally upgrade from dirtier fuels (animal dung, crop residues, wood, charcoal, and coal) to liquid fuels (kerosene) to gaseous fuels (liquid petroleum gas, natural gas, and biogas) and finally, sometimes, to electricity. Conversely, when prices of liquid and gaseous petroleum-based fuels rise, people tend to downgrade again to solid fuels—at least for certain tasks. As households move up the energy ladder, the fuels and stoves they use tend to become cleaner, more efficient, and easier to control—but also more costly. Because solid-fuel combustion for cooking is often inefficient and poorly controlled, the cost per meal prepared is generally not a simple function of the cost of the fuel or stove technology used.

Health and environmental impacts. The use of traditional fuels for cooking, often under poorly ventilated conditions, is a significant public health issue in many developing counties (Figure 1.5). Globally, exposure to smoke from household fuel combustion is estimated to be responsible for 1.6 million deaths annually, a death toll almost as high as that from malaria. Small children are disproportionately affected: they account for roughly 1 million of these deaths each year, usually from acute lower respiratory infections. Women are the next most affected group: they account for most of the remaining deaths, primarily from chronic pulmonary obstructive diseases (WHO, 2002).In addition to generating high levels of air pollution, extensive reliance on some traditional solid fuels—notably wood—can lead to unsustainable harvesting practices that in turn contribute to deforestation and generate other adverse impacts on local ecosystems. Moreover, some recent research suggests that biomass fuels used in cooking, even when they are harvested renewably (as crop residues and animal dung invariably are), can generate even higher overall greenhouse gas emissions than petroleum-fuel alternatives when emissions of non-carbon dioxide pollutants from incomplete combustion are accounted for (Smith and others, 2005).

Saving energy and saving lives. Several strategies have been tried in various places around the world to reduce the adverse impacts of cooking with solid fuels. Typically they combine simultaneous efforts to address three areas of opportunity: reducing exposure, reducing emissions, and using cleaner fuels. Options for reducing exposure include increasing ventilation, providing stoves with hoods or chimneys, and changing behavior. Options for reducing emissions include improving combustion efficiency, improving heat transfer efficiency, or preferably both. Fuel upgrades can involve switching to briquettes or charcoal (which creates problems of its own) and biogas. Several countries have subsidized shifts to kerosene and liquid petroleum gas in an effort to help poor households ‘leapfrog’ up the energy ladder. Smith (2002) has shown that if even a billion people switched from solid biomass cooking fuels to liquid petroleum gas, this would increase global emissions of carbon dioxide from fossil fuels by less than 1 percent. Emissions of greenhouse gases on an equivalent basis might actually decrease. Subsidizing cleaner fuels, however, suffers from several important drawbacks: it is expensive (India’s expenditures for liquid petroleum gas subsidies exceed all its expenditures for education); it is inefficient (government subsidies often end up benefiting households that do not need them); and it can actually increase household spending on energy as subsidized fuels get diverted to other uses (for example, kerosene and liquid petroleum gasare often diverted to transportation uses). Some countries, notably China, have implemented very successful programs to replace traditional cookstoves with cleaner models. Elsewhere, as in India, such programs have had mixed results.

In fact, U.S. citizens now consume electricity at a rate of roughly 14,000 kilowawtt hour per person per year while Europeans enjoy similar standards of living using, on average, only 7,000 kilowatt-hours per person per year.10 Improvements in energy efficiency represent one obvious opportunity to leverage multiple policy goals, but there are others — most notably, of course, changing the energy supply mix. To take an extreme example: if the resources used to meet energy needs were characterized by zero or near-zero greenhouse gas emissions, it would be possible to address climate-change risks without any reductions in consumption per se. In









Figure 1.5 The energy ladder: Relative pollutant emissions per meal
Note: Health-damaging pollutants per unit energy delivered: ratio of emissions to liquid petroleum gas (LPG). Using a log scale in Figure 1.5, the values are shown as grams per megajoule (g/MJ-d) delivered to the cooking pot.
Source: Smith and others, 2005.
















Figure 1.6 Relationship between human development index (HDI) and per capita electricity consumption, 2003 – 2004

Note: World average HDI equals 0.741. World average per capita annual electricity consumption, at 2,490 kWh per person.year, translates to approximately 9 gigajoules (GJ)/person.year [10,000 kilowatts (kWh) = 36 GJ]

Source: UNDP, 2006.

reality, of course, some combination of demand reductions and changes in the supply mix will almost certainly be necessary to meet the sustainability challenges of the coming century. Meanwhile, deploying renewable and other advanced, decentralized energy technologies can improve environmental quality, reduce greenhouse gas emissions, stimulate local economic development, reduce outlays for fuel imports, and make it more feasible to extend energy services to poor households, especially in remote rural areas.

Other factors complicate the sustainable energy challenge and further underscore the need for holistic policy approaches. A high degree of inertia characterizes not only the Earth atmosphere climate system but also much of the energy infrastructure that drives energy-usage patterns, as well as the social and political institutions that shape market and regulatory conditions. Because the residence times of carbon dioxide and other greenhouse gases in the atmosphere are on the order of decades to centuries, atmospheric concentrations of greenhouse gases cannot be reduced quickly, even with dramatic cuts in emissions. Similarly, the momentum behind current energy consumption and emissions trends is enormous: the average automobile lasts more than ten years; power plants and buildings can last 50 years or longer; and major roads and railways can remain in place for centuries. The growth that has recently occurred in worldwide wind and solar energy capacity is heartening, but there are very few examples of new energy forms penetrating the market by indefinitely sustaining growth rates of more than 20 percent per year. Fundamental changes in the world’s energy systems will take time, especially when one considers that new risks and obstacles almost always arise with the scaling up the deployment of new technologies, even if these risks and obstacles are hardly present when the technologies are first introduced. As a result, the process of transition is bound to be iterative and shaped by future developments and scientific advances that cannot yet be foreseen.

Precisely because there are unlikely to be any ‘silver-bullet’ solutions to the world’s energy problems, it will be necessary to look beyond primary energy resources and production processes to the broader systems in which they are embedded. Improving the overall sustainability of these systems requires not only appropriate market signals—including prices that capture climate change impacts and other externalities associated with energy use—but may also demand higher levels of energy-related investment and new institutions. Most current estimates of energy sector investment go only so far as delivered energy, but investments in the devices and systems that use energy—including investments in buildings, cars or airplanes, boilers or air conditioners—will arguably matter as much, if not more.11 In all likelihood, much of the required investment can be taken up in normal capital replacement processes. With estimated world income in 2005 of US$60 trillion (based on purchasing power parity) and an average capital investment rate close to US$1 trillion per month, there should be substantial scope to accelerate the deployment of improved technologies.

 1.4 Summary points

The multiple linkages between energy, the environment, economic and social development, and national security complicate the task of achieving sustainable outcomes on the one hand and create potentially promising synergies on the other.

    The scope and scale of the sustainable energy challenge require innovative, systemic solutions as well as new investments in infrastructure and technology. Much of the infrastructure investment will need to happen anyway, but in most places the market and regulatory environment is not currently providing the feedback signals necessary to achieve a substantial shift in business-as-usual patterns. And by several measures, current worldwide investment in basic energy research and development is not adequate to the task at hand.12
    Change will not come overnight. Essential elements of the energy infrastructure have expected life of the order of one to several decades. That means the energy landscape of 2025 may not look that different from the energy landscape of today. Nevertheless, it will be necessary within the next decade to initiate a transition such that by 2020 new policies are in place, consumer habits are changing, and new technologies are gaining substantial market share.
    The problem of unequal access to modern energy services is fundamentally a problem of distribution, not of inadequate resources or environmental limits. It is possible to meet the needs of the 2 billion-plus people that today lack access to essential modern forms of energy (i.e., either electricity or clean cooking fuels) while only minimally changing the parameters of the task for everyone else. For example, it has been estimated that it would cost only US$50 billion to ensure that all households have access to liquid petroleum gas for cooking. Moreover, the resulting impact on global carbon dioxide emissions from fossil-fuel use would be on the order of 1or 2 percent (IEA, 2004; 2006). Reducing current inequities is a moral and social imperative and can be accomplished in ways that advance other policy objectives.
    A substantial course correction cannot be accomplished in the timeframe needed to avoid significant environmental and energy-security risks if developing countries follow the historic energy trajectory of already industrialized countries. Rich countries, which have consumed more than their share of the world’s endowment of resources and of the absorptive capacity of the planet’s natural systems, have the ability and obligation to assist developing countries in ‘leapfrogging’ to cleaner and more efficient technologies.
    To succeed, the quest for sustainable energy systems cannot be limited to finding petroleum alternatives for the transport sector and low-carbon means of generating electricity—it must also include a set of responsible and responsive demand-side solutions. Those solutions must address opportunities at the city level (with special focus on the use of energy and water), new energy-industrial models (incorporating modern understanding of industrial ecology), and advanced mobility systems. In addition, it will be necessary to focus on opportunities at the point of end-use (cars, appliances, buildings, etc.) to implement the widest range of energy-saving options available. Most of the institutions that frame energy policy today have a strong supply-side focus. The needs of the 21st century call for stronger demand-side institutions with greater country coverage than is, for example, provided by the IEA with its largely industrialized country membership.
    Given the complexity of the task at hand and the existence of substantial unknowns, there is value in iterative approaches that allow for experimentation, trying out new technologies at a small scale and developing new options. Science and engineering have a vital role to play in this process and are indispensable tools for finding humane, safe, affordable, and environmentally responsible solutions. At the same time, today’s energy challenges present a unique opportunity for motivating and training a new generation of scientists and engineers.
    The experience of the 20th century has demonstrated the power of markets for creating prosperous economies. Market forces alone however will not create solutions to shared-resource problems that fall under the ‘tragedy-of-the-commons’ paradigm (current examples include international fishing, water and air pollution, and global warming emissions). 13 Governments have a vital role to play in defining the incentives, price signals, regulations, and other conditions that will allow the market to deliver optimal results. Government support is also essential where markets would otherwise fail to make investments that are in society’s long-term best interest; examples include certain types of infrastructure, basic research and development, and high-risk, high-payoff technologies.


DFID (Department for International Development). 2002. Energy for the Poor: Underpinning the Millennium Development GoalsLondon, United Kingdom.

IEA (International Energy Agency). 2006. World Energy Outlook 2006. Paris.
——. 2005. Energy Balances of Non-OECD Countries 2002-2003. International Energy Agency, Paris.

IPCC (Intergovernmental Panel on Climate Change). 2007a. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change. Cambridge University Press:Cambridge, United Kingdom and New York, NY, USA.