Company

Mainspring Energy, Inc.

Mainspring Energy makes linear generators for onsite power for commercial and industrial users, based in Menlo Park, US.

About

Founded in 2010 and based in Menlo Park, US, Mainspring Energy, Inc., formerly EtaGen, Inc., makes the Mainspring Linear generator for onsite power in commercial, industrial, grid and microgrid settings. Customers can buy the generator directly or pay only for electricity produced under an energy services agreement. Shannon Miller is the founder and CEO. In April 2025, the company raised USD 258 million in Series F funding led by General Catalyst Partners, with participation from Amazon, Dcvc and Temasek Holdings.

8Funding rounds

16Investors

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