Bill Gates’ Breakthrough Energy Backs New Battery Startup (1)

Bill Gates’ Breakthrough Energy Ventures is backing a new thermal storage startup, expanding its investments in long-duration power backup.

Fourth Power converts renewable power to heat, storing it for future use. Relying on liquid tin, the thermal battery transfers heat to stacks of carbon blocks at extremely high temperatures, which can later be discharged as electricity through thermophotovoltaic cells. Doing so could help solve intermittency issues with renewables.

Investor DCVC led the Series A round of $19 million, with participation from Breakthrough and Black Venture Capital Consortium. Fourth Power plans to build a prototype facility that can store the ...