Worcester Business Journal

30 Worcester Business Journal | Book of Lists 2026 | wbjournal.com Largest clean energy companies Ranked by number of local employees Company Local employees/ companywide Type of business Products and services Top executive(s)/ year founded 1 Babcock Power Services, Babcock Power Environmental 26 Forest St., Suite 300, Marlborough 01752 508-852-7100 • babcockpower.com 500 (1) N/A Technology, equipment and engineering services Solar, biomass and waste-to-energy Wade Shephard president & CEO, Babcock Power Services & Babcock Power Environmental Michael Leclair president & CEO, Babcock Power Inc. 1913 1 Milton CAT 100 Quarry Drive, Milford 01757 508-634-3400 • miltoncat.com 500 (1) N/A Caterpillar machines for power generation and energy storage Includes MC2 Renewable Energy Services, a full- service renewable energy division within Milton CAT Chris Milton president & CEO 1960 3 Commonwealth Fusion Systems (CFS) 117 Hospital Road, Devens 01434 781-606-1233 • cfs.energy 330 (2) 1,000 (3) Fusion energy systems Alcator C-Mod compact, high-magnetic field tokamak, high-temperature superconducting (HTS) magnets for fusion energy generation Bob Mumgaard CEO 2018 4 Aspen Aerogels Inc. 30 Forbes Road, Northborough 01532 508-691-1111 • aerogel.com 189 1,124 Development and manufacturing of aerogels for clean energy and electrification Solutions to thermal runaway challenges in electric vehicle market Don Young president & CEO 2001 5 LG Energy Solution Vertech Inc. 155 Flanders Road, Westborough 01581 508-497-7319 • lgensol-vt.com 172 356 Energy storage systems integration Battery energy storage systems with software & services Jaehong Park CEO 2014 (4) 6 Electric Hydrogen 33 Jackson Road, Devens 01434 N/A • eh2.com 150 (5) 300 (6) Hydrogen Electrolyzer technologies to enable abundant, low- cost, and clean hydrogen with gigafactory in Devens Raffi Garabedian CEO & co-founder 2020 7 Ameresco Inc. 111 Speen St., Suite 410, Framingham 01701 866-263-7372 • ameresco.com 144 1,597 Energy infrastructure solutions Smart energy efficiency solutions, infrastructure upgrades, and development, construction & operation of distributed energy resources George Sakellaris president & CEO Michael Bakas president, renewable fuels 2000 8 Solect Energy 87 Hayden Rowe St., Hopkinton 01748 508-598-3511 • solect.com 120 N/A Commercial solar development & operations, with more than 910 installations, 730 current customers & 185 MW of solar energy installed Commercial solar & storage solutions John Bodt president & CEO 2009 9 Ostrow Electric Co. 9 Mason St., Worcester 01609 508-754-2641 • ostrowelectric.com 107 165 Electrical infrastructure from bidding to design-build and engineering Photovoltaic systems for rooftop & large-scale ground mount, wind turbine generators Matthew Ostrow president 1939 10 AMSC 114 E. Main St., Ayer 01432 978-842-3000 • amsc.com 100 (7) 1,195 Technologies for grid and wind segments Wind turbine system designs licensed under Windtec Solutions with products & services for wind turbine manufacturers Daniel McGahn president & CEO 1987 11 Ascend Elements (8) 133 Flanders Road, Westborough 01581 508-936-7701 • ascendelements.com 95 (9) 300 (9) Battery materials manufacturing & recycling Custom lithium-ion battery materials, cathode precursor (pCAM) and lithium carbonate, from recycled batteries & manufacturing scrap; lithium-ion battery recycling services to manufacturers & electric vehicle OEM's Linh Austin president & CEO 2015 12 Endless Energy New England Inc. 261 Cedar Hill St., Suite 100, Marlborough 01752 508-357-2354 • goendlessenergy.com 73 73 HVAC systems installation & service, Mass Save contractor, insulation, plumbing, electrical Home energy assessments, weatherization & insulation, electrical service upgrades, e-vehicle charging stations Matt Kidd president Amanda Perkins chief operating officer 1980 13 Donahue & Sons 123 Cut Off Road, Barre 01005 508-380-2082 • donahuesons.com 65 65 Operation and maintenance of solar installations Vegetation management, solar panel washing, solar panel snow removal, critical infrastructure repair Tom Donahue president 2010 14 Modern Energy 24 Rockdale St., Worcester 01606 508-449-0449 • modernenergynow.com 40 40 Renewable energy and electrification design & installation Commercial variable refrigerant flow (VRF) heat pumps, residential mini split heat pumps; insulation, solar photovoltaic, roofing & LED lighting upgrades John Pitcavage Jeff Vlk co-founders 2017 15 NORESCO (10) One Research Drive, Suite 400C, Westborough 01581 508-614-1000 • noresco.com 40 425 Energy and water infrastructure, sustainability consulting, decarbonization Distributed & renewable energy, storage, savings performance contracting, microgrids, engineering, integration, operations and maintenance, codes & standards, procurement, commissioning, retrofits Troy Walters president & CEO 1984 16 ThinkLite Air LLC 117 West Central St., Suite 201, Natick 01760 617-500-6689 • thinklite.com 34 (9) N/A Indoor air monitoring and purification solutions Indoor air quality monitor with automated alerts, LED light panel and medical-grade air purifier, large space portable medical-grade air purifier Dinesh Wadhwani founder & CEO 2009 17 New England Clean Energy Inc. 577 Main St., Suite 430, Hudson 01749 978-567-6527 • newenglandcleanenergy.com 32 (9) N/A Solar panel and battery installation and service Solar panels and batteries for small to midsized commercial & residential systems Evan Vana CEO Mark Durrenberger (11) founder & president 2006 18 SolarFlair Energy Inc. 289 Elm St., Suite 203, Marlborough 01752 508-293-4293 • solarflair.com 23 (12) N/A Solar contractor Installation and service Jeffrey Constantine president 2007 19 CLEAResult Inc. 112 Turnpike Road, Suite 111, Westborough 01581 888-812-6146 • clearesult.com 21 2,940 Energy efficiency, transition and sustainability services in North America Energy efficiency, transition, consulting, analytics and sustainability services Rich McBee president & CEO Vic Pisani chief operating officer 2003 Source: Each company via survey as of Q2 2026. Note: Marlborough's Ambri was liquidated in November 2025. N/A=not available. (1) Local employee count falls within a range of 500 to 999, according to Mass. Executive Office of Labor and Workforce Development. (2) From cfs.energy/devens-campus/overview (3) From WBJ's 2026 Power 100 questionnaire (4) Founding year for NEC Energy Solutions (5) Estimate based on press releases and news reports (6) As of Q3 2025 (7) Local employee count falls within a range of 100 to 249, according to Mass. Executive Office of Labor and Workforce Development. (8) In April 2026, filed for Chapter 11 bankruptcy, with no plans to close Westborough R&D facility, nor conduct layoffs as of filing (9) From WBJ's 2025 survey (10) Part of Carrier Global Corp. (NYSE: CARR) (11) Also, Evan Vana, chief operating officer (12) From WBJ's 2024 survey -Compiled by: Stephanie R. Meagher, research@nebusinessmedia.com F O C U S P R O F E S S I O N A L S E R V I C E S

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