Sara Mattern

Washington, DC

At Foley Hoag, we are focused on the mission of fighting climate change through innovation and collaboration.

Sara Mattern guides emerging companies, investors and renewable energy companies on financings and strategic development. She works with clients in the clean energy, climate, sustainability, bluetech and technology sectors on innovative technologies and business approaches to solving energy and sustainability challenges.

Sara acts as general outside counsel to emerging companies on all aspects of their business, including early-stage formation and structuring matters, venture financings, strategic alliances and acquisitions. Sara also works with incubators and accelerators to support the development of their member companies.

Sara is an active member of the firm’s Energy Project Finance and Development practice. Sara works with sponsors, investors and developers on all aspects of renewable energy project development, tax equity, sponsor equity and debt financings, acquisitions, tax credits and state incentives, with a particular focus on distributed generation solar projects.


  • Boston College Law School, J.D., cum laude
  • Georgetown University, B.S.F.S., cum laude

Bar and Court Admissions

  • District of Columbia
  • Massachusetts


  • Spanish


  • Leading independent power producer Soltage, LLC in a $250 million partnership with investment management firm Harrison Street to fund solar and other clean energy infrastructure assets developed by Soltage 
  • Spring Lane Capital in investments in distributed waste water and composting infrastructure investments 
  • AEGON USA Realty Advisors (an affiliate of Transamerica) in connection with tax equity investments in North Carolina solar portfolios totaling 100MW and 30MW, respectively
  • A sponsor equity investor in its investment in a portfolio of over 30MW of wind and solar PV
  • Solar developers and investment managers in multiple acquisitions of solar project portfolios
  • Soltage, LLC in connection with a $140 million equity capital partnership with Basalt Infrastructure Partners LLP and various joint ventures, project acquisitions, tax equity and back leverage financings, and other financing transactions
  • Greenwood Energy, a division of a diversified family-owned business, in US solar financing activities, including hybrid construction and permanent lending facilities, tax equity financings and back leverage lending facilities
  • GoldenSet Capital Partners in connection with $50 million sponsor equity and tax equity investments for a portfolio of Massachusetts solar projects
  • Advise sponsors and developers in back leverage debt financings of solar assets
  • NODAR Inc., a maker of 3D vision software for autonomous vehicles, in a $12 million Series A financing lead by NEA, and its previous in $2.7 million Series Seed Financing 
  • Modern Electron, Inc., a sustainable heat and power startup, in $30 million Series B financing 
  • Energetic Insurance, a Managing General Underwriter, in a $7 million Series A financing led by Schneider Electric Ventures, with participation from MS&AD Ventures, Atlantic Global Risk, and MCJ Collective 
  • Kula Bio, Inc. in $50 million Series A financing
  • Prime Impact Fund as lead investor in multiple climate-tech companies
  • MyA Health, Inc. in equity financing led by Pillar VC
  • KnipBio, Inc. in venture financings and strategic collaborations
  • Vergent Bioscience, Inc. in $11 million Series A financing
  • Tank Utility, Inc. in multiple equity financings
  • Recorded Future, Inc. in multiple venture financings, including $25 million Series E round
  • A leading residential energy efficiency provider in multiple equity financings
  • Altaeros Energies, Inc. in a Series A financing led by Softbank Corp.
  • Recorded Future, a threat intelligence company, in its sale of a controlling interest in the company valued at $780 million to Insight Partners
  • Tank Utility, Inc., leading provider of remote monitoring services for truck-delivered energy, in its sale to Generac Power Systems
  • 7AC Technologies, a developer of ultra-high efficiency HVAC systems, in its sale to Emerson Electric
  • Sun Catalytix in sale to Lockheed Martin
  • Alere Inc. in its $600 million sale of Alere Health, LLC to Optum
  • A U.S. based developer of gas-to-liquid projects in their sale of the company to Velocys plc


  • Note, “Municipal Energy Benchmarking Legislation for Commercial Buildings: You Can't Manage What You Don't Measure,” 40 Boston College Environmental Affairs Law Review 487 (2013)
  • Comment, “FYI to the FAA on FLL: Approval of a Runway Extension in City of Dania Beach” 39 Boston College Environmental Affairs Law Review E. Supp. 69 (2012)

Honors & Involvement

  • The Best Lawyers in America: Ones to Watch for Energy Law and Venture Capital Law
  • Ranked by Venture Capital Journal as one of venture capital's 40 rising stars (2021) 
  • Greater Boston Chamber of Commerce, Women’s Leadership Program: 2018-2019 
  • Greentown Labs, Advisory Board Member
  • SeaAhead, Advisory Board Member
  • Georgetown University, Expert in Residence for Georgetown Entrepreneurship Initiative
  • Women’s Bar Association, Member
  • New England Women in Energy and the Environment, member
  • Foley Hoag Foundation, Grant Proposal Reviewer
  • Cleantech Open, Judge and Mentor
  • Women’s Energy Network, Member, Boston chapter

Speaking Engagements

  • Panelist, “Valuation: Insights for Success from Investors and Entrepreneurs” ecosVC Tough Ventures series (November 12, 2021) 
  • Speaker, “The Role of an Attorney for Cleantech Startups” Cleantech Open (July 26, 2021)
  • Speaker, “Choice of Entity Considerations,” 2021 BizGrow Conference, Lawyers for Civil Rights (July 22, 2021)  
  • Panelist, “Legal Challenges for a Cleantech Startup,” Cleantech Open Academy (June 4, 2021)  
  • Panelist, “The Future of Sustainability,” Angel Capital Association Fall Forum (October 27, 2020) 
  • Speaker, “Business Formation Considerations for Clean Energy Businesses,” Cleantech Open 2020 (July 30, 2020) 
  • Speaker, “Choice of Entity Considerations,” 2020 BizGrow Conference, Lawyers for Civil Rights (July 16, 2020) 
  • Speaker, “Legal Challenges for a Cleantech Startup,” Cleantech Open East Coast Academy (June 2, 2020) 
  • Moderator, “Development and Financing Trends in the Northeast,” Solar and Energy Storage Northeast Forum (February 19, 2020) 
  • Panelist, “The Future of Electric Vehicles,” Women’s Energy Network, Boston Chapter (November 19, 2019) 
  • Speaker, “Equity Compensation Basics for Startups,”  Greentown Labs (October 30, 2019)
  • Speaker, “Out of the Incubator: Finding Office Space for Startups,” Massachusetts Clean Energy Center and City of Somerville (October 30, 2019)
  • Webinar, "Preparing for Investors: Understanding Term Sheets and Financings" (August 5, 2019) 
  • Speaker, “Legal Challenges for a Cleantech Startup,” Cleantech Open East Coast Academy (June 12, 2018)