David Gardiner
Principal, President

David Gardiner has more than 35 years of experience analyzing and shaping successful domestic and global clean energy and sustainability strategies in both the public and private sectors.  As principal of David Gardiner and Associates, he provides high-level strategic guidance to the corporate executives and non-profit leaders with whom the firm works. Among his principal areas of expertise are energy efficiency, clean air policy, sustainable transportation, and forest and land issues. David uses this knowledge, coupled with his strong ability to make sense of complicated issues, to help clients develop informed, thoughtful strategies to maximize bottom line impact.

Prior to founding DGA, David served as the Executive Director of the White House Climate Change Task Force during the Clinton Administration, where he participated in development of domestic policy and in international climate negotiations. As EPA’s Assistant Administrator for Policy, David led EPA’s climate change efforts, as well as programs to reinvent EPA’s approaches to key sectors such as transportation, agriculture, metal finishing and real estate development. Prior to joining the Clinton administration, David was Legislative Director for the Sierra Club in Washington, DC. David has a Bachelor of Arts with honors from Harvard College.

Contact David

david@dgardiner.com, 703.717.5590


Ryan Hodum
Vice President

Ryan Hodum has more than a decade of experience helping businesses and non-profit organizations understand complex sustainability challenges and capture opportunities, especially focused on energy policy, energy efficiency and renewable energy. Ryan leads DGA’s work with Chambers for Innovation and Clean Energy, a coalition of more than 400 local chambers of commerce supporting clean energy, and DGA’s work with Fortune 500 companies, who are purchasing renewable energy and cutting their greenhouse gas emissions. He is a co-author of DGA’s Power Forward report series, assessing the clean energy targets of Fortune 500 companies and has built partnerships and alliances to advance clean energy policy across dozens of states and at the federal level. Ryan’s strong strategy and communication skills have helped the Retail Industry Leaders Association launch its Retail Energy Management Program to transform the way the industry uses energy.

Prior to joining DGA, Ryan worked at the U.S. Department of State to expand renewable energy and energy efficiency in China and India. He helped the World Resources Institute identify global supply chain bottlenecks in the wind turbine industry. Ryan has a Bachelor of Arts in International Relations and Hispanic Studies from the College of William and Mary, and has earned Master of Arts in Global Environmental Policy from American University. He speaks fluent Spanish.

Contact Ryan

ryan@dgardiner.com, 703.717.5590


Jennifer Kefer
Vice President

Jennifer Kefer has nearly 15 years of experience providing legal and political expertise, strategic analysis, and advice to non-profits, corporations and cities on a range of projects related to climate, energy and other environmental issues. Her expertise in industrial efficiency, EPA regulations and compliance, alliance and partnership-building, and policy engagement guides her work leading DGA’s work for the Alliance for Industrial Efficiency – a coalition of business, labor, and non-profit groups supporting policies to advance Combined Heat and Power. Jennifer’s leadership and advocacy have helped the Alliance and other groups successfully press the Environmental Protection Agency to incorporate industrial efficiency and Combined Heat and Power into Clean Air Act rules, such as the carbon pollution New Source Performance Standards for new and existing power plants and the Industrial Boiler MACT. She has urged state Public Utility Commissions to adopt policies that encourage CHP. She also leads DGA’s work on Carbon Capture and Storage, and is coordinating a coalition of groups to advance policies to support it.

Jennifer’s previous experience includes grassroots education and outreach, federal advocacy, legal research and analysis, and environmental litigation working on behalf of a range of organizations, including Environmental Defense Fund, the Center on Budget and Policy Priorities, and Earthjustice. She earned a B.A. in environmental studies at Brandeis University, a Masters of Environmental Studies at the Yale School of Forestry and Environmental Studies and a J.D. at the Yale Law School.

Contact Jennifer

jennifer@dgardiner.com, 202.816.9302


Alexandra Rekkas
Senior Research Associate

Alexandra Rekkas has over six years of consulting experience in the energy efficiency and renewable energy fields. She comes to DGA from Booz Allen Hamilton, where she provided project management support for a federal energy client, the Advanced Research Projects Agency – Energy (ARPA-E). In this role, she coordinated activities related to the funding selection process for high-impact advanced energy research and development programs. Before joining Booz Allen Hamilton, Alexandra worked as an analyst for an environmental consulting firm, The Cadmus Group, where she specialized in energy efficiency program evaluation.

Alexandra earned a B.S. in Animal Science at Cornell University and dual Master’s degrees in Public Affairs and Environmental Science from Indiana University, with concentrations in Environmental Policy and Natural Resource Management and Applied Ecology.

Contact Alexandra

alexandra@dgardiner.com, 703.717.5590


Isabel Harrison
Research Associate

Isabel Harrison has a background in strategic communications and environmental policy, with a particular focus on water and climate policy. At DGA, Isabel is responsible for conducting research and providing operational support for the DGA team. She also manages the website and coordinates communications efforts related to renewable energy and industrial efficiency.

Isabel earned a B.A. in environmental studies with minors in political science and Africana studies from Dickinson College. During her time as an undergraduate, Isabel studied and conducted research in Yaoundé, Cameroon, and Copenhagen, Denmark, which propelled her interest in sustainability and clean energy into professional goals.

Contact Isabel

isabel@dgardiner.com, 703.717.5590