American Electric Power, Chevron and Equinor all participated in a round that increased the power generation technology developer's total funding to $228m.

US-based, on-site power generation technology developer Mainspring Energy received $95m on Tuesday in a series D round featuring energy utility American Electric Power (AEP) and oil and gas producers Chevron and Equinor.

The round was led by Devonshire Investors, a private equity firm affiliated with financial services and investment group Fidelity, and included Princeville Capital, 40 North Ventures, Khosla Ventures, ClearSky, KCK Group and private investor Bill Gates.

Chevron was represented in the round by its corporate venturing unit, Chevron…