Khosla-Backed Startup Nabs $258 Million to Power Data Centers

A startup that builds novel generators has raised $258 million, fueled by the tailwinds of power-hungry artificial intelligence.

Mainspring Energy Inc. counts among its customers a unit of NextEra Energy Inc., one of the world’s biggest renewable energy suppliers, as well as a growing number of data center customers that use the company’s so-called linear generators as a source of power. The technology works by creating a flameless reaction of air and fuel that helps produce electricity.

“The demand has been really quite outstanding,” said Samir Kaul, founding partner and managing director at Khosla Ventures, a follow-on investor who ...