May 4, 2021 - Energy & Environment

Distributed power startup Mainspring lands $95 million in new funding

Mainspring's linear generator.

Mainspring's linear generator. Photo courtesy of Mainspring.

The distributed generation company Mainspring Energy has raised $95 million in new funding led by Fidelity Investment's private equity arm, alongside other new and existing backers like Chevron, Princeville Capital and Bill Gates.

Why it matters: There's growing interest in low-carbon onsite power sources as a way to fight climate change and to create more flexibility and resilience as grids are increasingly stressed by extreme weather.

How it works: The Bay Area firm's technology, called a "linear generator," is designed to run on multiple fuels.

  • It uses a "low-temperature reaction of air and fuel to drive magnets through copper coils to efficiently produce electricity."
  • CEO Shannon Miller has likened it to "an air hockey table that you’ve wrapped around into a tube."

Where it stands: Mainspring — founded by Stanford engineers in 2010 and formerly called EtaGen — said the new money brings its total capital raised to $228 million.

  • The Series D financing will enable Mainspring to add customer deployments, expand manufacturing and add staff, the company said.
  • It comes about two months after Mainspring announced a $150 million deal with power heavyweight NextEra Energy Resources to buy Mainspring units and finance customer projects.

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