The renewable energy sector in Connecticut is a robust, thriving industry offering a variety of innovative and sustainable solutions. Companies in this diverse sector vary from clean energy generators to solar technology innovators. They offer an array of products and services such as solar racking systems, environmentally-friendly energy solutions, and clean energy itself. The industry is dynamic, constantly evolving to meet the ever-increasing demand for renewable, sustainable energy. It aims to make clean energy an accessible and affordable norm while conscientiously protecting our natural environment. This progressive direction is potentially paving the way for a green energy-fueled future.


Top 19 renewable energy companies in Connecticut

1. AVANGRID, Inc. (formerly UIL Holdings Corporation)

  • Website: avangrid.com
  • Headquarters: Orange, Connecticut, United States
  • Founded: 1852
  • Headcount: 5001-10000
  • LinkedIn

Avangrid is a leading clean energy company that generates and delivers energy from sustainable, renewable sources. They actively work to protect and enhance the natural environment.


2. GameChange Solar

  • Website: gamechangesolar.com
  • Headquarters: Norwalk, Connecticut, United States
  • Founded: 2012
  • Headcount: 51-200
  • Latest funding type: Series Unknown
  • LinkedIn

GameChange Solar is a company that is changing the world by making solar energy affordable. They offer innovative solar racking systems and solutions to maximize solar energy production.


3. Specialized Technology Resources, Inc.

  • Website: strsolar.com
  • Headquarters: Enfield, Connecticut, United States
  • Founded: 1944
  • Headcount: 201-500
  • Latest funding type: Ipo
  • LinkedIn

STR Holdings, Inc. is a global leader in solar panel encapsulation, offering environmentally-responsible solutions through research and innovation.


4. Louth Callan Renewables

Louth Callan Renewables develops, constructs, and maintains clean, renewable-energy projects in the United States, specializing in solar solutions. They offer workmanship warranties and operations and management agreements to ensure optimal functioning of the systems. LCR procures top-level equipment manufacturers and investment-grade panels for their projects.


5. Greenskies Clean Focus

  • Website: greenskies.com
  • Headquarters: North Haven, Connecticut, United States
  • Founded: 2009
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Greenskies is a vertically-integrated solar energy company offering decarbonization solutions like onsite and offsite solar, battery storage, microgrids, and CCHP. They are dedicated to quality and operational excellence and work with commercial, public sector, and utility energy users throughout the US. With a single delivery team, Greenskies originates, develops, constructs, and operates renewable energy facilities.


6. Altus Power, Inc.

  • Website: altuspower.com
  • Headquarters: Stamford, Connecticut, United States
  • Founded: 2009
  • Headcount: 51-200
  • Latest funding type: Post Ipo Debt
  • LinkedIn

Altus Power offers locally-sited solar generation, energy storage, and EV-charging stations to customers across the U.S. Find savings and reliable renewable energy for commercial, industrial, public sector, and Community Solar customers.


7. Greenworks Lending from Nuveen

  • Website: greenworkslending.com
  • Headquarters: Darien, Connecticut, United States
  • Founded: 2015
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Greenworks Lending is a company that offers financing solutions for energy efficiency projects. They specialize in C-PACE (Commercial Property Assessed Clean Energy) financing, which allows property owners to fund upgrades and improvements with no upfront costs. Their services include project types such as new construction, gut rehabs, energy efficient upgrades, solar and renewables, and recapitalization for recently completed projects. They also provide resources like case studies, available states, and FAQs. Greenworks Lending aims to make the world greener by providing loans for sustainable projects.


8. Steven Winter Associates

  • Website: swinter.com
  • Headquarters: Norwalk, Connecticut, United States
  • Founded: 1972
  • Headcount: 51-200
  • LinkedIn

SWA is a company that specializes in providing innovative energy efficiency, sustainability, and accessibility solutions for buildings. They offer services such as green building certification, energy optimization, and accessibility consulting for both residential and commercial construction projects. With a focus on improving the built environment, SWA has been in operation since 1972.


9. Budderfly

  • Website: budderfly.com
  • Headquarters: Shelton, Connecticut, United States
  • Founded: 2007
  • Headcount: 51-200
  • Latest funding type: Acquired
  • LinkedIn

Budderfly is an energy efficiency company that helps businesses modernize their facilities to be brighter, more comfortable, and more efficient. They offer a unique Energy Efficiency-as-a-Service solution, providing all the technology and investment in efficiency upgrades without any out-of-pocket costs. Their services include constant monitoring, maintenance, and upgrades such as LED lighting, HVAC systems, Budderfly IOT sensors, renewable energy sourcing, and more.


10. Green Street Power Partners

  • Website: gspp.com
  • Headquarters: Stamford, Connecticut, United States
  • Founded: 2000
  • Headcount: 11-50
  • LinkedIn

Green Street Power Partners (GSPP) is a company that focuses on acquiring, financing, and developing solar energy systems across the nation. They offer community solar solutions and aim to power tomorrow with clean and sustainable energy.


11. CTEC Solar

  • Website: ctecsolar.com
  • Headquarters: Windsor, Connecticut, United States
  • Founded: 2010
  • Headcount: 51-200
  • LinkedIn

CTEC Solar is a company that specializes in the development and installation of utility-scale solar projects in the Northeast. They offer a range of solutions for commercial and residential customers, including solar farms, rooftops, carports, and residential homes.


12. Savkat INC

  • Website: savkat.com
  • Headquarters: Bristol, Connecticut, United States
  • Founded: 1985
  • Headcount: 11-50
  • LinkedIn

SAVKAT is a solar energy provider that offers top quality products and services. They specialize in home solar systems and provide a comprehensive warranty that covers the entire system. SAVKAT is committed to customer satisfaction and offers financing options for convenience.


13. Evolutionary Home Energy Solutions

Evolutionary Home Energy is a provider of energy-efficient home improvement solutions and technologies, including solar energy systems and efficient home insulation.


14. Murphy International Development LLC

Murphy International Development is a global energy project development, management and financing company offering renewable and conventional power solutions including wind, solar, hydrogen, geothermal, and biomass.


15. Solomon Energy

Solomon Energy is an energy advisory firm that assists clients in implementing solar, wind, energy storage and supply projects to meet their sustainability goals and lower costs.


16. AltEnergy, LLC

AltEnergy LLC is an entrepreneurial investor in alternative energy projects.


17. SHR Energy Management

  • Website: shrenergy.com
  • Headquarters: Weston, Connecticut, United States
  • Founded: 2011
  • Headcount: 11-50
  • LinkedIn

SHR Energy Management is a consulting firm that provides solutions for solar energy development and infrastructure at utility-scale. They offer services for planning, designing, and implementing solar projects.


18. Catalyst Financial Group, Inc.

Catalyst Financial Group, Inc. offers customized funding solutions to assist clients in maximizing their financial objectives. The company provides fast innovative financing to renewable energy, energy efficiency, water and waste-water integrators and developers.


19. GoldenSet Capital Partners LLC

GoldenSet Capital is an investment firm specializing in sustainable infrastructure.


Want to find more renewable energy companies?


If you want to find more companies that offer innovative, sustainable energy solutions and solar technologies you can do so with Inven. This list was built with Inven and there are hundreds of companies like these globally.


With Inven you'll also get to know the company's:


  • Ownership: Which of these are private equity backed? Which are family-owned?
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...and a lot more!