Prepublication Copy – Subject to Further Editorial Correction Accelerating Decarbonization of the U.S. Energy System ADVANCE COPY NOT FOR PUBLIC RELEASE BEFORE February 2, 2021 at 11:00 a.m. ___________________________________________________________________________________ PLEASE CITE AS A REPORT OF THE NATIONAL ACADEMIES OF SCIENCES, ENGINEERING, AND MEDICINE Committee on Accelerating Decarbonization in the United States Board on Energy and Environmental Systems Division on Engineering and Physical Sciences A Consensus Study Report of PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION THE NATIONAL ACADEMIES PRESS 500 Fifth Street, NW Washington, DC 20001 This activity was supported by the Alfred P. Sloan Foundation, Heising-Simons Foundation, Quadrivium Foundation, Gates Ventures, ClearPath Foundation, and Incite Labs, with support from the National Academy of Sciences Thomas Lincoln Casey Fund, National Academy of Sciences Arthur L. Day Fund, and National Academy of Sciences Andrew W. Mellon Foundation Fund. Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of any organization or agency that provided support for the project. International Standard Book Number-13: 978-0-309-XXXXX-X International Standard Book Number-10: 0-309-XXXXX-X Digital Object Identifier: https://doi.org/10.17226/25932 Additional copies of this publication are available for sale from the National Academies Press, 500 Fifth Street, NW, Keck 360, Washington, DC 20001; (800) 624-6242 or (202) 334-3313; http://www.nap.edu. Copyright 2021 by the National Academy of Sciences. All rights reserved. Printed in the United States of America Suggested citation: National Academies of Sciences, Engineering, and Medicine. 2021. Accelerating Decarbonization of the U.S. Energy System. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/25932. PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org. PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION Consensus Study Reports published by the National Academies of Sciences, Engineering, and Medicine document the evidence-based consensus on the study’s statement of task by an authoring committee of experts. Reports typically include findings, conclusions, and recommendations based on information gathered by the committee and the committee’s deliberations. Each report has been subjected to a rigorous and independent peer-review process and it represents the position of the National Academies on the statement of task. Proceedings published by the National Academies of Sciences, Engineering, and Medicine chronicle the presentations and discussions at a workshop, symposium, or other event convened by the National Academies. The statements and opinions contained in proceedings are those of the participants and are not endorsed by other participants, the planning committee, or the National Academies. For information about other products and activities of the National Academies, please visit www.nationalacademies.org/about/whatwedo. PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION COMMITTEE ON ACCELERATING DECARBONIZATION IN THE UNITED STATES: TECHNOLOGY, POLICY, AND SOCIETAL DIMENSIONS STEPHEN W. PACALA, NAS,1 Princeton University, Chair COLIN CUNLIFF, Information Technology and Innovation Foundation DANIELLE DEANE-RYAN, Libra Foundation KELLY SIMS GALLAGHER, Tufts University Fletcher School JULIA HAGGERTY, Montana State University, Bozeman CHRISTOPHER T. HENDRICKSON, NAE,2 Carnegie Mellon University JESSE D. JENKINS, Princeton University ROXANNE JOHNSON, BlueGreen Alliance TIMOTHY C. LIEUWEN, NAE, Georgia Institute of Technology VIVIAN LOFTNESS, Carnegie Mellon University CLARK A. MILLER, Arizona State University, Tempe WILLIAM A. PIZER, Duke University VARUN RAI, University of Texas, Austin ED RIGHTOR, American Council for an Energy-Efficient Economy ESTHER TAKEUCHI, NAE, Stony Brook University SUSAN F. TIERNEY, Analysis Group JENNIFER WILCOX, Worcester Polytechnic Institute Staff K. JOHN HOLMES, Study Director, Board Director/Scholar, Board on Energy and Environmental Systems ELIZABETH ZEITLER, Senior Program Officer, Board on Energy and Environmental Systems BRENT HEARD, Associate Program Officer, Board on Energy and Environmental Systems KASIA KORNECKI, Associate Program Officer, Board on Energy and Environmental Systems CATHERINE WISE, Associate Program Officer, Board on Energy and Environmental Systems MICHAELA KERXHALLI-KLEINFIELD, Research Associate, Board on Energy and Environmental Systems REBECCA DEBOER, Research Assistant, Board on Energy and Environmental Systems HEATHER LOZOWSKI, Financial Business Partner, Board on Energy and Environmental Systems CYNDI TRANG, Research Associate, Board on Health Care Services RANDY ATKINS, Director, Communications/Media, National Academy of Engineering (until July 2020) JENELL WALSH-THOMAS, Program Officer, Board on Environmental Change and Society MICAH HIMMEL, Senior Program Officer, Transportation Research Board DAVID BUTLER, Holloman Scholar, National Academy of Engineering NOTE: See Appendix B, Disclosure of Conflict(s) of Interest. 1 Member, National Academy of Sciences. 2 Member, National Academy of Engineering. PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION v BOARD ON ENERGY AND ENVIRONMENTAL SYSTEMS JARED COHON, NAE,1 Carnegie Mellon University, Chair VICKY BAILEY, Anderson Stratton Enterprises CARLA BAILO, Center for Automotive Research W. TERRY BOSTON, NAE, GridLiance GP, LLC, and Grid Protection Alliance DEEPAKRAJ DIVAN, NAE, Georgia Institute of Technology MARCIUS EXTAVOUR, XPRIZE KELLY SIMS GALLAGHER, Tufts University Fletcher School T.J. GLAUTHIER, TJ Glauthier Associates, LLC NAT GOLDHABER, Claremont Creek Ventures DENISE GRAY, LG Chem Michigan, Inc. JOHN KASSAKIAN, NAE, Massachusetts Institute of Technology BARBARA KATES-GARNICK, Tufts University DOROTHY ROBYN, Boston University JOSÉ SANTIESTEBAN, NAE, ExxonMobil Research and Engineering Company ALEXANDER SLOCUM, NAE, Massachusetts Institute of Technology JOHN WALL, NAE, Cummins, Inc. (retired) ROBERT WEISENMILLER, California Energy Commission (former) Staff K. JOHN HOLMES, Director/Scholar ELIZABETH ZEITLER, Senior Program Officer BRENT HEARD, Associate Program Officer KASIA KORNECKI, Associate Program Officer CATHERINE WISE, Associate Program Officer MICHAELA KERXHALLI-KLEINFIELD, Research Associate REBECCA DEBOER, Research Assistant HEATHER LOZOWSKI, Financial Manager JAMES ZUCCHETTO, Senior Scientist 1 Member, National Academy of Engineering. PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION vi Preface Over the past two decades, increased understanding of the severity of impending climate change has coincided with rapid development of non-emitting energy technologies, including significant reductions in their costs. As a result, many nations, states, cities, and companies have recently indicated goals and are developing plans to transition to an energy system that emits zero net anthropogenic greenhouse gases (GHGs), usually by midcentury. This timetable would allow the transition to take advantage of the natural turnover of long-lived capital stock (i.e., the 30-year lifetime of a gas power plant) and is consistent, if adopted globally, with limiting the global temperature increase to substantially less than 2 degrees Celsius. Because the energy system impacts so many aspects of society, a transition to net zero would have profound implications well beyond climate and energy, including economic competitiveness, increased employment, and improved human health. If done right, a transition to net zero might provide more and better-quality jobs, and economic benefits that exceed costs. A transition might also provide an opportunity to eliminate injustices that permeate our current energy system, such as the disproportionate exposure of historically marginalized groups to toxic fossil pollutants. Public support for a decades-long transition could be maintained only by fairly distributing