Mainspring closes $290M Series E Round

Mainspring closes $290M Series E Round

Mainspring Closes Series E at $290 Million


Mainspring Energy, Inc.

Sep 21, 2022, 09:00 ET


MENLO PARK, Calif., Sept. 21, 2022 /PRNewswire/ -- Clean power generation provider Mainspring Energy Inc. today announced the final close of its Series E financing at $290 million.

On May 24th this year, simultaneously with announcing a major commercial sales deal, Mainspring disclosed it had completed its first close of the Series E at $150 million. The company has since expanded the raise by an additional $140 million, to reach the $290 million Series E final close. 

Mainspring will use the funds to expand operations and scale manufacturing of its innovative clean energy generators. Global growth equity investor Lightrock led the Series E, joined by Canada Pension Plan Investment Board (CPP Investments), Shell Ventures, Hanwha Power Systems, and other new private investors, along with existing investors Khosla Ventures, Bill Gates, Fine Structure Ventures (the private equity firm affiliated with parent company Fidelity Investments), Princeville Capital, and others.

"The world-class group of investors in our Series E represents some of the top clean energy and climate investors in the world," said Mainspring CEO and Founder Shannon Miller. "They are deeply committed to meeting our mutual goal of clean, reliable, affordable power for all."

Mainspring will use the funds to expand operations and scale manufacturing of its innovative clean energy generators for commercial, industrial, and grid-side customers. Mainspring Linear Generators deliver significant advantages in cost, reliability, and flexibility, including the ability to dynamically switch between clean fuels like biogas, hydrogen, and ammonia with software. The products' full dispatchability allows them to track and firm renewables like solar and wind, and their low emissions make them easily sited and permitted. They can be deployed as a single unit or as a grid-scale array, ranging in output from 230 kW to tens of megawatts of power.

About Mainspring Energy

Based in Menlo Park, Calif., Mainspring is delivering a breakthrough new category of clean power generation — the linear generator — to leading customers including Fortune 500 companies like Kroger and Lineage Logistics, and utilities AEP, PG&E, Florida Power and Light, and more. For more information visit

SOURCE Mainspring Energy, Inc.