Our Team

Optimal Energy is a highly respected team of energy efficiency and energy policy experts. We offer sound research methods, reliable analyses, and actionable recommendations to clients across the country. We keep our core group small and nimble, then expand resources as needed with top-tier external partners. Please contact any Optimal Energy staff member to learn more about our consulting services.

When needed, we invite key specialized partners from across the nation to form dedicated project teams that deliver strategies and results beyond what any one company can deliver.


Eric has been a Partner since 2000. He brings over thirty years of development, sales, operations and management experience in the energy, agricultural, construction and manufacturing industries to his work in energy efficiency. He specializes…

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ADRIAN CAESAR Senior Analyst

Adrian joined Optimal Energy in 2019, working from our Rhode Island office. He provides analysis for the full range of Optimal Energy’s work, including potential studies, program planning and implementation oversight, and EM&V. With experience…

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Gretchen joined Optimal Energy in 2012. She provides research and analytical support for clients on a range of projects including advisory council, technical services, potential studies, white papers and policy reports, and expert testimony. In…

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DOUGLAS GILMAN Senior Consultant

Doug joined Optimal Energy in 2022. Doug provides energy efficiency consulting in the multiple forms of program design, implementation, and evaluation for energy efficiency programs for states and utilities in the region. He advises clients…

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MAT HIMMELEIN State Technical Program Monitor

Mat joined Optimal Energy in 2018 as the State Technical Program Monitor for the Delaware Weatherization Assistance Program (WAP). Mat is a Building Performance Institute certified Quality Control Inspector under WAP protocols and also holds…

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Craig joined Optimal Energy in 2014 as an Analyst. Since joining the team, he has provided core analytical and technical support for many of Optimal Energy’s efforts to promote energy efficiency and renewable energy. In…

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Griff joined Optimal Energy in 2020, working from our Vermont office. He provides analysis for the full range of Optimal Energy’s work, including potential studies, program planning and implementation oversight, and EM&V. With experience in…

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MICHELLE KELLER Senior Consultant

Michelle joined Optimal in 2021.   She has over thirty years of experience in the commercial & industrial sector and combines her knowledge of energy efficiency programs to advocate for the needs and sustainability goals of…

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Cliff first joined Optimal Energy in 2006. He has experience with various policy and technical issues relating to energy efficiency, renewable energy, and LEED certification. His energy experience includes potential studies, program design, cost effectiveness…

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Samartha works on data modeling and analysis on a wide variety of projects. By way of background, he has worked on researching energy policy issues, studying emissions regulations, and designing solar rooftop systems. The diversity…

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Phil co-founded Optimal Energy in 1996. With over 35 years of experience in all aspects of energy efficiency, he specializes in efficiency and distributed energy policy, innovative program administration models, integrated energy resource planning, cost-benefit…

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SAM ROSS Senior Consultant

Sam joined Optimal Energy in 2017 upon graduating from the London School of Economics with Distinction in his Master of Science in Environmental Economics and Climate Change. Sam is involved in a wide range of…

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GEORGE SAKELARIS Regional Sales Manager

George has over twenty-five years of experience in management, Business Development, Sales, Marketing, Financial Planning, Solution Selling, Start-Up Experience and Business Management. He has expertise in many facets of business management, new business development, partner…

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MATTHEW SOCKS Senior Consultant

Matt joined Optimal Energy in 2007 and serves a leading role in efficiency program design, engineering, economic analysis, and implementation support for clients across North America. With expertise in the field of efficiency measure research…

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