Our Team

Optimal Energy has assembled a stellar team of energy efficiency and energy policy experts. We offer sound research methodologies, reliable analytics, and actionable recommendations to clients across the country. Our internal team is small enough to provide fast, personalized service to all our clients. We also bring in expertise from established external partners as needed to expand our resources on larger, more complex projects.

Over the years, Optimal has built a reputation based on solid results and satisfied clients. We hire professionals who are excellent communicators as well as top analysts and engineers. We complete projects on time and on (or under) budget. Please contact one of our partners, or any Optimal staff member to learn more about our consulting services.

We bring deep knowledge and proven analytics to the table, plus excellent communication skills, on behalf of regulators and other organizations.
We invite key partners from across the nation to join our project teams, which allows Optimal to develop programs and provide leading edge strategy beyond what any one company can deliver.


Philip Mosenthal

Ph: 802-482-5607


Phil co-founded Optimal in 1996 after acting as Chief Consultant for XENERGY’s (now DNV GL) Mid-Atlantic office. With over 25 years of experience in all aspects of energy efficiency, Phil specializes in program design and planning for the business, institutional and industrial sectors. Phil has directly implemented programs and assisted numerous clients throughout the U.S. and internationally to develop and analyze efficiency portfolios, design leading edge programs, analyze integrated efficiency and supply-side resources, develop strategic models for large scale efficiency delivery, and develop evaluation plans and oversee evaluation activities. Phil currently serves advisory roles for the Massachusetts Energy Efficiency Advisory Council and Rhode Island Energy Efficiency Resource Management Council, among others. Phil has an M.S. in Energy Management and Policy and a B.A. in Architecture, both from the University of Pennsylvania.

Eric Belliveau

Ph: 802-482-5606


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 in efficiency program design, implementation support, direct install program approaches, financing strategies, and customer account management. Eric’s clients have included dozens of Program Administrators and efficiency stakeholders in several states and international jurisdictions. Among his roles, Eric is the head consultant to the Massachusetts Energy Efficiency Advisory Council where he leads a team of national experts in advising the Council as it oversees implementation of one of the most advanced efficiency portfolios in the country. Eric has a B.A. in International Affairs with emphasis on Economics and German from the University of Maine, 1981. He is LEED accredited.

Managing Consultants

Mike Guerard

Ph: 802-482-5616


Mike joined Optimal in 2008. He has over 20 years of experience in the energy efficiency, green building and the renewable energy industry. He has developed and managed a wide-range of energy efficiency programs throughout New England and the Pacific Northwest; renewable energy and green building initiatives; and building science training and education forums. In addition to overseeing dozens of efficiency program staff, he has worked collaboratively with a wide range of stakeholders to achieve positive program results and significant energy savings. Working out of Optimal’s Rhode Island office, Mike provides critical cross-program development and implementation for a wide range of clients. He has a B.A from the University of Rhode Island.

Elizabeth Chant

Ph: 802-482-5626


Elizabeth joined Optimal Energy in 2018, bringing more than two decades of experience in low-income sustainable energy policy and programming. She was at Vermont Energy Investment Corporation (VEIC) from 2010 through 2018, most recently as a Principal Consultant. Major projects included leading the successful proposal development for VEIC’s DC Sustainable Energy Utility (DC SEU) in 2010 and again when the work was rebid in 2016. She was part of the team that launched the DC SEU in 2011, when she served as the first Low-Income Multifamily Program Manager. She also led the development of its recent five-year strategic plan and multiple annual plans.  Prior to returning to VEIC, Elizabeth served for eight years as Weatherization Director at Champlain Valley Weatherization, Vermont’s largest provider of low-income weatherization services. While there, she improved efficiency of operations by more than 40%, readying the agency for a doubling of production during the ARRA period. Prior to that, she was at VEIC, leading its award-winning multifamily programming. Elizabeth currently serves on the boards of directors of National Housing Trust and Three3 and has previously served on the boards of directors of the Home Performance Coalition Affordable Comfort, the National Energy and Utility Affordability Coalition, and the Vermont Low-Income Advocacy Council.

Senior Consultants

George Lawrence

Ph: 802-482-5630


George has over 12 years of renewable energy and energy efficiency sales and consulting experience. His efficiency experience includes performing investment grade audits; planning, and program design; efficiency and renewable energy potential studies; research on renewable energy and energy efficiency technologies; and the design and implementation of strategic energy management programs. He currently acts as the commercial and industrial technical consultant for the energy efficiency program advisory boards in Massachusetts, Rhode Island and Connecticut. George is a nationally recognized expert in snowmaking energy efficiency and has presented on this topic at many national conferences. He is also a Certified Practitioner of Energy Management Systems-Industrial, and is an expert in the implementation and maintenance of the ISO 50001 Energy Management standard. George graduated from Middlebury College with a degree in Physics (1989) and holds certifications as a Certified Energy Manager and a Certified Energy Auditor.

Matthew Socks

Ph: 802-482-5614


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 and characterization, he has developed standardized methodologies for determining savings from efficiency measures and programs in more than a dozen states. Matt has served as a primary contributor to numerous energy efficiency potential analyses, many of which have formed the foundation for jurisdictional efficiency savings targets. An experienced analyst, he has led targeted market research efforts on both building segments and efficient technologies. Matt holds a B.S. in Mechanical Engineering from the Massachusetts Institute of Technology and is a licensed Professional Engineer in the State of Vermont.

Mark Kravetz, Senior Consultant

Ph: 802-482-5638


Mark joined Optimal Energy in 2016. He has experience in the areas of low-income energy efficiency programs, building sciences, non-energy benefits, green job workforce development, healthy housing, public health and social service systems optimization.   Mark has demonstrated success with developing and managing complex housing initiatives focused on creating government efficiency and program cost savings by integrating and streamlining energy efficiency, healthy housing and health related services with a proven multi-sector bottom line return on investment. These initiatives have honed Mark’s project management and coalition building skills to deliver data driven outcomes among a diverse array of stakeholders including federal, state and municipal government, utilities, community action agencies, housing contactors, higher education, hospitals, FQHCs, philanthropy and non-profits. Mark works out of Optimal’s Rhode Island office and holds a B.A. in Public & Community Service Studies from Providence College.


Cliff McDonald

Ph: 802-482-5618


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 screenings, cash flow analysis, M&V protocol development, and implementation support. Recent projects at Optimal include completing reports on performance incentives and Pennsylvania’s Act 129; working on program design and PUC filings for New York, Washington D.C., and Rhode Island; analyzing the electric-sector GHG emission reductions under the NY State Climate Action Plan; and working on a potential analysis for NYPA. Cliff has a B.S. in Physics from Middlebury College.

Gretchen Calcagni head shot

Ph: 802-482-5615


Gretchen joined Optimal 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 particular, Gretchen provides on-going planning and analysis support to the Massachusetts Energy Efficiency Advisory Council. While in graduate school, she interned at Rocky Mountain Institute to help develop strategies for improving energy efficiency in the affordable housing sector. Gretchen received a Master of Public Policy from Duke University with a focus on energy and environmental policy and a B.A. in Sociology from the University of Virginia.

Sam Ross

Ph: 802-482-5631


Sam joined Optimal 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 work at Optimal Energy, and provides support to core analytical tools within the energy efficiency potential assessment framework. His prior work experience includes four years as a data scientist and programmer, during which he worked at a proprietary trading firm specializing in energy markets, and a non-profit company focused on promoting data access and transparency in seniors housing real estate markets. Sam particularly enjoys working in R, SQL, ArcGIS and MATLAB, which he employed during his recent MSc as well as during his undergraduate education at Dartmouth College, where he graduated Magna Cum Laude in 2012.

Adam Jacobs

Ph: 802-482-5645


Adam is an experienced energy professional with a background in environmental analysis, economics, and energy engineering. Adam recently came to Optimal Energy from his position as Energy Manager for the City of Boston, where he led Boston’s successful efforts to maintain the top position as #1 in the ACEEE City Energy Efficiency Scorecard. Prior to that, Adam was an Energy Analyst at Johnson Controls, serving as the primary measurement and verification specialist on a multi-million dollar energy savings performance contract.  As an intern while at school, Adam also gained experience with Boston-based organizations EnerNOC and Ceres.  Adam has an M.S. in Energy Systems from Northeastern University (with a Certificate in Energy Leadership) and B.A. in Environmental Analysis and Policy from Boston University.

Senior Analysts

Craig Johnson

Ph: 802-482-5629


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 doing so, he researches and analyzes energy efficiency and renewable technologies, programs, and evaluations to support strategic planning and implementation. Craig also provides technical and analytical support in the form of screening projects for cost-effectiveness and drafting communications pieces. Prior to joining Optimal Energy, Craig interned with Acadia Center (f.k.a. Environment Northeast), where he helped to support many of the organizations core programs, including its sustainable transportation team. He received his M.S. in Climate Science and Policy from Bard College’s Center for Environmental Policy, where he wrote his thesis on the modeled lifetime private costs of electric vehicle ownership. Craig also has a B.S. in Atmospheric Sciences from Lyndon State College.


Caesar - Headshot for website - July 2019

Ph: 802-482-5640


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 in statistical modeling and data analysis, Adrian supports project work across the Optimal portfolio, including cleaning and analyzing data from Rhode Island and Massachusetts efficiency programs.  Adrian received his B.A. in the Business, Entrepreneurship, and Organizations Economics track from Brown University.

Office Manager

April Clodgo

Ph: 802-482-5621

April provides Optimal and its clients with coordination, editing, presentation, bookkeeping and computer support.