May 4, 2021 - Energy & Climate

Distributed power startup Mainspring lands $95 million in new funding

Ben Geman

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.

Go deeper: Clean energy patenting is outpacing fossil fuels, but experts warn it's not enough

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Distributed power startup Mainspring lands $95 million in new funding

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