Energy Efficiency Thought Leaders
This page honors innovators and experts who have helped shape the field of energy efficiency. The Pioneers category recognizes individuals we view as having had some of the most significant impacts. Our Trailblazers are also recognized leaders in the field with focus areas ranging from clean energy policy to energy efficient utilities to bringing appliance efficiency standards to China. We invite you to explore their contributions, insights, and impacts.
Pioneers
Art Rosenfeld (b.1926 - d.2017) — Former Commissioner, California Energy Commission
Widely known as the “Godfather of Energy Efficiency,” Art built the field of energy efficiency from the ground up. In the wake of the 1970s oil crisis, Art—trained as a physicist under Enrico Fermi—founded and led the Center for Building Science at the Lawrence Berkeley National Lab where he and his team developed several energy-efficient technologies that became the backbone of modern efficiency standards: low-emissivity windows, electronic ballasts, appliance efficiency standards, and modeling tools for energy use in buildings. The work of Art and his team at Berkeley Lab directly informed California’s Title 24 building code (adopted in 1978) and helped lay the foundation for national energy efficiency standards. These policies have collectively avoided the need for dozens of power plants and prevented billions of tons of CO₂ emissions.
Physicists who knew Art coined the term “Rosenfeld Effect” to describe the decoupling of energy use from economic growth and proposed the “Rosenfeld” as a unit for electricity savings—equal to 3 billion kWh per year, or the output of one coal plant avoided. Art served ten years as a California Energy Commissioner and was awarded the National Medal of Technology and Innovation in 2012. His legacy lives on in the policies, technologies, and institutions that continue to reduce energy waste worldwide.
Amory Lovins — Cofounder, Chair Emeritus, Former CEO and Chief Scientist, and 43-year Trustee of RMI (founded as Rocky Mountain Institute)
A renowned energy visionary, Amory’s revolutionary ideas about energy efficiency, renewable energy, and a world without fossil fuels have shaped public energy discourse for more than five decades. He has advised major firms and governments in more than 70 countries. A prolific lecturer and author, Amory has largely or wholly written more than 900 papers and 32 books, including the groundbreaking works Natural Capitalism and Reinventing Fire. Learn more about Amory and his rich body of work on our dedicated Amory Lovins page.
David Goldstein (b.1951 - d.2024) — Co-Founder, New Buildings Institute; former Senior Scientist, Natural Resources Defense Council
As a mentee of Art Rosenfeld, David built on Art’s legacy across his career, providing visionary leadership in efforts to make energy efficiency an integral part of mitigating climate change. During his 43 years at the Natural Resources Defense Council, David developed national appliance standards (such as those for refrigerators and air conditioners), programs to decouple utility profits from energy sales, and building codes. These efforts have saved consumers billions and avoided hundreds of millions of tons of CO₂. David co-founded the New Buildings Institute, Institute for Market Transformation, and Consortium for Energy Efficiency to scale these strategies across sectors and regions. His work helped launch Energy Star and cut energy use in commercial buildings by 50% or more.
Ralph Cavanagh — Energy Program Co-Director and Senior Attorney (retired), Natural Resources Defense Council (NRDC)
Ralph spent 44 years at NRDC focusing on removing barriers to cost-effective energy efficiency and promoting the role of utilities in leading the clean energy transition by rewarding saving energy over selling it. His success in persuading regulators of the merits of this unconventional approach helped prove that utility regulatory reform is viable and yields substantial environmental gains. Although recently retired, Ralph remains active in the clean energy space, serving as Chair of the Board of Advisors for the UC Davis Energy and Efficiency Institute and as a board member for the Bonneville Environmental Foundation. He received the Lifetime Achievement in Energy Efficiency Award from California’s Flex Your Power campaign.
Gilbert Masters — Professor Emeritus, Civil and Environmental Engineering, Stanford University
Gil’s 50+ year career has focused on energy efficiency and renewable energy systems as essential keys to enhancing energy security and improving conditions in underserved, rural communities. A beloved professor since the mid-1970s, he’s taught more than 10,000 students at Stanford University, offering courses like "Energy-Efficient Buildings" and "Electric Power: Renewables and Efficiency." He is also the author or co-author of ten books, including Renewable and Efficient Electric Power Systems, an essential resource for engineers and practitioners in the climate and energy field.
John Holdren — Heinz Research Professor of Environmental Policy, Harvard Kennedy School
John has been a leading voice in energy policy for over five decades. As President Obama’s top science advisor and Director of the White House Office of Science and Technology Policy (2009-2017), John helped shape national policy on climate change, clean energy, and energy efficiency. Earlier, at UC Berkeley, he co-founded UC Berkeley’s Energy and Resources Group and later led Harvard’s Program on Science, Technology, and Public Policy. A physicist and policy expert, John’s work has shaped how science informs energy and environmental decision-making around the world.
Trailblazers
Peter Bradford — Adjunct professor, Vermont Law School
Peter Bradford has played a key role in shaping U.S. nuclear and utility policy for over 50 years. As an NRC Commissioner after the Three Mile Island accident, he helped lead critical reforms in nuclear safety and regulation. He later chaired state utility commissions in Maine and New York, advancing energy efficiency, competitive markets, and environmental protection. Internationally, he has advised over 20 countries on electricity regulation and nuclear policy.
Marilyn Brown — Regents' and Brook Byers Professor of Sustainable Systems, Georgia Institute of Technology
After 22 years at Oak Ridge National Lab, Marilyn Brown founded Georgia Tech’s Climate and Energy Policy Lab where she continues to shape national policy through research on carbon reduction and utility business models. As a board director (2010-2018) for the Tennessee Valley Authority, Marilyn led efforts to cut emissions in half, integrate a “virtual power plant,” and bring a new nuclear reactor online.
Keep up with Marilyn on LinkedIn →
Kateri Callahan — Founder and Principal, Dynamic Energy Strategies; Former President, Alliance to Save Energy
Kateri is a leading national voice for energy efficiency policy and advocacy. As President of the Alliance to Save Energy from 2004 to 2018, she led campaigns that helped shape appliance and vehicle efficiency standards, building codes, and federal programs like Energy Star—returning billions in energy savings to consumers and businesses. Kateri grew the Alliance to be a globally respected force through policy leadership, public outreach, and its flagship EE Global Forum. Today, she continues advancing clean energy as founder of Dynamic Energy Strategies and as advisor to top universities, nonprofits, and industry.
Sheryl Carter — Senior Strategist, Power Sector, Natural Resources Defense Council (NRDC)
Sheryl has played a pivotal role in clean energy transformation, overseeing NRDC’s work to modernize the U.S. power sector for greater equity, affordability, and environmental benefit. At NRDC, she leads strategies to scale energy efficiency and electrification while ensuring energy benefits reach all communities. With over 20 years of national leadership, she has shaped state policies, advised utilities, and served on the Electric Power Research Institute’s Advisory Council.
Sue Coakley — Founder and Executive Director (retired), Northeast Energy Efficiency Partnerships (NEEP)
In 1996, Sue founded NEEP, the U.S.'s first Regional Energy Efficiency Organization. Under her leadership, NEEP helped states adopt leading efficiency policies, advance building performance standards, and reduce per capita energy use. A longtime advocate and policy expert, Sue also served at the Massachusetts Department of Public Utilities and worked as a consultant before launching NEEP. She retired in 2020 after more than 30 years of advancing clean energy.
Richard Cowart — Principal, Regulatory Assistance Project (RAP)
Rich has spent his career improving how electricity systems are planned, regulated, and made more sustainable. He chaired the Vermont Public Service Board (1986–1999), leading electric industry reforms in the U.S. and advising the DOE on grid policy. At RAP, Rich led international work in the EU, China, and the U.S. to support cleaner, more efficient power markets.
Tom Eckman — Director of Power Planning (retired), Northwest Power and Conservation Council
Over a 30+ year career at the Council, Tom co-authored all seven regional power plans, establishing the region as a national model for utility-scale energy efficiency. As Power Division Director, he assessed energy efficiency as a resource and led the creation of the Regional Technical Forum, which he chaired for 16 years. He also helped launch the Northwest Energy Efficiency Alliance, which later named its Lifetime Achievement Award in his honor.
Ashok Gadgil — Distinguished Professor Emeritus, University of California, Berkeley
Ashok has used energy efficiency to improve the lives of millions of low-income communities around the world. During his four-decade career at Lawrence Berkeley National Lab and UC Berkeley, he led a research team to develop and implement efficient lighting appliances for underserved households, fuel-saving stoves for refugee camps (Berkeley-Darfur Stove), and low-cost technologies for clean drinking water (UV Waterworks and ECAR). In 2023, Ashok was awarded the National Medal of Technology and Innovation for his life-saving innovations.
Keep up with Ashok on LinkedIn →
Margie Gardner — Vice President and Senior Advisor, Resource Innovations
As the founding Executive Director of Northwest Energy Efficiency, Margie launched 30+ award-winning programs that continue to generate regionwide savings—enough to power over 670,000 homes annually. Earlier, at the Natural Resources Defence Council, Margie co-authored the Northwest's first least-cost plan, helping to avert unnecessary fossil and nuclear infrastructure. Today, she helps lead California’s new Market Transformation Administrator (CalMTA), focusing on equity-centered efficiency solutions.
Keep up with Margie on LinkedIn →
Howard Geller — Founder, Board Member, Senior Policy Advisor, and former Executive Director, Southwest Energy Efficiency Project (SWEEP); Former Executive Director, American Council for an Energy-Efficient Economy (ACEEE)
Howard has been a driving force behind U.S. energy efficiency policy for over four decades. He founded SWEEP in 2001 and led it for 20 years, shaping efficiency and clean transportation policies across six western states. Before SWEEP, he served as Executive Director of ACEEE where he built the organization’s national influence on energy standards, programs, and legislation. Geller played a key role in advancing federal efficiency laws, including the National Appliance Energy Conservation Act (1987) and the Energy Policy Act (1992), and has advised utilities, federal agencies, and international bodies. His global impact includes helping launch Brazil’s national energy efficiency program, PROCEL.
Meg Gottstein — Principal (retired), The Regulatory Assistance Project (RAP)
Meg has been contributing to the energy efficiency field since the 1970s. As a U.S. DOE regional program manager serving under the Carter Administration, she was responsible for scaling up a pilot program to commercialize renewable and energy efficiency technologies for region-wide implementation. Meg also worked as a consultant to the National Governors Association on renewable energy and energy efficiency before joining the California Public Utilities Commission (CPUC) as an Administrative Law Judge. During her 20-year tenure at the CPUC, she became known as a key architect of the Commission’s energy efficiency and climate change policy decisions. Meg joined RAP in 2008, where she worked on projects in the U.S., Chile, and Europe, with a particular focus on European power market reform.
Blair Hamilton (b.1949-d.2011) — Co-Founder, Vermont Energy Investment Corporation (VEIC)
Blair co-founded VEIC in 1986 and was the visionary behind Efficiency Vermont, the first "energy efficiency utility" in the United States. A passionate advocate for treating efficiency as a resource, Blair promoted that the cheapest energy is the energy we don’t use. His legacy includes pioneering work in utility-funded demand-side programs, heat recovery ventilation research, and integrated planning approaches that have reshaped how utilities and governments deliver energy benefits.
Jeff Harris — Chief Transformation Officer, Northwest Energy Efficiency Alliance (NEEA)
Jeff has led energy efficiency programs across commercial, residential, and industrial sectors for decades at NEEA. His earlier roles at the Bonneville Power Administration and the Northwest Power and Conservation Council helped shape energy codes and regional power plans. As a co-founder of the Northwest Building Commissioning Collaborative and New Buildings Institute (NBI), Jeff has advanced national leadership in building performance and energy-efficient design.
Keep up with Jeff on LinkedIn →
Hal Harvey — Founder Emeritus, Energy Innovation
Hal has spent more than three decades designing policy and infrastructure to mitigate climate change, with a focus on systems-level levers that deliver wide-scale results. His work has influenced fuel economy standards, utility regulation, and building energy use, enabling billions of tons of CO₂ abatement. Hal founded Energy Innovation in 2012 to promote effective and equitable energy policies focused on the world’s largest emitting countries and economic sectors. Prior to that, he founded and led the Energy Foundation and ClimateWorks, philanthropies supporting energy and climate policy and solutions. Hal has also published hundreds of papers and four books, including Designing Climate Solutions: A Policy Guide for Low-Carbon Energy.
Nancy Hirsh — Executive Director, Northwest (NW) Energy Coalition
For nearly 30 years, Nancy has advanced regulatory and legislative energy efficiency policies and programs in the Northwest. At the NW Energy Coalition, she directs efforts to enhance investments in energy efficiency, renewable resources, and low-income energy services across the region by working closely with utilities, regulators, advocates, and lawmakers. Before joining the Coalition, Nancy spent over a decade in Washington, D.C. advancing national energy policy with the Environmental Action Foundation and the National Wildlife Federation.
Keep up with Nancy on LinkedIn →
Mark Levine — Senior Staff Scientist, Lawrence Berkeley National Laboratory (LBNL)
Mark is a pioneer in energy efficiency policy and analysis. As Director of LBNL’s Environmental Division (1996-2006), Mark led over 400 staff in advancing research on building energy efficiency, indoor air quality, and clean energy technologies. In 1988, Mark founded LBNL's China Energy Group, launching a decades-long U.S.-China collaboration that helped bring appliance efficiency standards to China—saving more energy than five times the output of the Three Gorges Dam. He also co-authored the 2007 Intergovernmental Panel on Climate Change (IPCC) Assessment Report, which shared the Nobel Peace Prize.
Paul MacCready (b.1925—d.2007) — Founder, AeroVironment
Paul's 50+ years-long career laid the foundation for today’s solar, electric, and ultra-light transportation systems. In 1977, Paul designed the Gossamer Condor, the world’s first successful human-powered aircraft, and in 1979, the Gossamer Albatross, which crossed the English Channel on pedal power alone. Paul founded AeroVironment in 1971 to develop clean transportation technologies, and his team later built the Solar Challenger, the first solar-powered aircraft to complete a long-distance flight. Paul and his team also developed Helios, a high-altitude solar drone. On land, MacCready led the development of the GM Sunraycer, which won the 1987 World Solar Challenge, and the GM Impact, an early electric vehicle.
Alan Meier — Adjunct Professor, University of California, Davis; Senior Scientist, Lawrence Berkeley National Laboratory
Alan’s pioneering research has transformed how the world thinks about appliance energy use. He led the global charge against “vampire power,” launching the G8-endorsed 1-Watt Initiative to reduce standby energy losses—responsible for about 1% of global CO₂ emissions. As founding editor of the Home Energy journal and author of Saving Electricity in a Hurry, Alan has influenced international policy, utility programs, and consumer behavior. His ongoing research at UC Davis focuses on behavior, equipment performance, and rapid-response efficiency strategies.
Harvey Michaels — Lecturer at MIT Sloan
Harvey has spent decades bridging energy innovation, policy, and community action. At MIT, he teaches Energy Management Innovation and leads research on clean heat systems and climate-resilient cities. A former CEO of energy analytics firms Xenergy and Aclara, Harvey helped shape smart grid technologies and energy efficiency programs nationwide. He also played a key role in major MIT studies on the future of the electric grid and community energy systems. Today, he advises cities, states, and federal agencies on how to integrate clean energy into everyday life.
Keep up with Harvey on LinkedIn →
Steven Nadel — Executive Director, American Council for an Energy-Efficient Economy (ACEEE)
For over two decades, Steve led ACEEE to grow from a small team to a national powerhouse for research and advocacy. He helped shape nearly every major federal efficiency policy in the U.S. such as appliance standards, tax incentives, and low-carbon technologies, including a $6 billion Inflation Reduction Act industrial decarbonization program. Steve personally helped negotiate efficiency standards for over 25 types of products and led efforts to make efficiency programs more equitable, using tools like state scorecards and programs that make clean technologies easier to adopt. His work helped keep U.S. energy use flat for years, even as the economy and population grew.
Danny Parker — Principal Research Scientist, Florida Solar Energy Center (FSEC), University of Central Florida
Danny has spent decades studying how homes use energy and how to use a lot less of it. He holds 30+ patents and led dozens of field studies on home energy use, producing retrofit strategies to cut household energy consumption by 40% or more. Danny invented the Gossamer Wind® ceiling fan, saving U.S. users over $40M annually in electricity, and now in nearly 2 million homes. Danny also developed the solar-powered Anywhere Fan for off-grid cooling and disaster relief. His work has helped make energy efficiency more practical and powerful, especially in hot, humid climates like Florida.
Gene Rodrigues — Former Assistant Secretary for Electricity, U.S. Department of Energy (DOE)
Gene is a nationally recognized leader in electricity policy, energy efficiency, and public service. From 2023 to 2025, he served as Assistant Secretary for Electricity at the U.S. DOE, overseeing efforts to modernize the U.S. power grid and improve electric reliability. Before his Senate-confirmed appointment, Gene led market development at ICF and spent over two decades at Southern California Edison, where he directed demand-side programs benefiting more than 15 million customers. Gene has shaped state and national energy policy through roles on the boards of ACEEE, the California Efficiency & Demand Management Council, and the Consortium for Energy Efficiency, among others. His work has advanced low-income energy access, equitable electrification, and cross-sector climate action.
Keep up with Gene on LinkedIn →
Peter Rumsey — President and Founder, Decarbonization Strategies, Inc.; Former CEO and Founder, Point Energy Innovations; Adjunct Lecturer, Civil and Environmental Engineering, Stanford University
Peter is widely recognized as an innovator and leader in low energy buildings and building decarbonization. He has designed some of the U.S.'s most innovative mechanical, electrical, and plumbing (MEP) systems and pioneered the use of radiant cooling in office buildings. In his 40+-year career, Peter has designed more LEED Platinum, Zero Energy, and radiant cooled buildings than any other engineer in the U.S. Peter also values educating others about energy efficient buildings. He founded the Stanford Building Decarbonization Learning Accelerator, which provides curated teaching materials (for free!) to college educators so they can teach the next generation of architects, engineers, and construction managers about building decarbonization. Peter is a registered professional engineer (PE) in 10 states, a certified energy manager, and an ASHRAE fellow.
Keep up with Peter on LinkedIn →
Dan Sperling — Founding Director, UC Davis Institute of Transportation Studies
Dan is a global leader in low-carbon transportation policy. As founding director of the UC Davis Institute of Transportation Studies, he built one of the world’s foremost research centers on clean mobility. During 16 years on the California Air Resources Board, Dan shaped landmark policies including the Low Carbon Fuel Standard and regulations promoting electric vehicles and efficient fuels. He chaired the World Economic Forum’s Future of Transportation Council, testified to Congress eight times, authored 250+ papers and 13 books, and served on more than a dozen National Academies committees on energy and transport. Dan was elected to the National Academy of Engineering in 2022.
Joel Swisher — Former Managing Director, RMI (formerly Rocky Mountain Institute); Adjunct Professor, Civil and Environmental Engineering, Stanford University; Director Emeritus, Institute for Energy Studies, Western Washington University
With more than 40 years’ experience in clean energy technology, Joel is an expert in energy efficiency technology and policy, carbon offsets and climate change mitigation, and electric utility resource planning and economics. He has consulted with numerous utilities, manufacturers and technology companies on resource planning, energy efficiency, vehicle electrification and clean energy deployment strategies. As RMI’s former managing director of research and consulting, Joel led teams that used whole-systems thinking to help companies around the world achieve ambitious energy efficiency targets. Joel is also an innovator in energy-focused training for engineers. He designed the curriculum for Western Washington University’s Institute for Energy Studies, one of the nation’s first interdisciplinary energy programs for undergraduates, and currently teaches Extreme Energy Efficiency with Amory Lovins at Stanford.