Chris Sacca’s VC firm is raising a second nuclear fusion fund

Billionaire investor Chris Sacca is doubling down on his bet that nuclear fusion will become a cornerstone of the global clean energy transition. His climate-focused venture capital firm, Lowercarbon Capital, is raising a second fund dedicated to fusion startups, Sacca announced at the SOSV Climate Tech Summit on Thursday, according to Bloomberg.

The new fund follows Lowercarbon’s $250 million fusion-focused fund launched in 2022, which backed several of the field’s leading companies. A source told Bloomberg that the new vehicle is expected to be larger than the first.

Fueling the Race for Fusion

Lowercarbon Capital has already invested in Commonwealth Fusion Systems (CFS) — one of the sector’s most prominent players — as well as emerging innovators like Pacific Fusion.

CFS, a spinoff from the Massachusetts Institute of Technology (MIT), raised $863 million earlier this year after securing $1.8 billion in Series B funding in 2021. These massive rounds underscore the capital-intensive nature of fusion energy development.

“Fusion believers still hold faith that the breakthrough needed to make it commercially viable is just around the corner,” Sacca said, echoing optimism shared by fellow climate tech investors such as Vinod Khosla and other major fusion backers.

A Costly, High-Stakes Frontier

While recent scientific advances — including sustained plasma stability and improved magnet performance — suggest fusion energy could one day be commercially achievable, building reactors remains extraordinarily expensive.

TechCrunch previously reported that more than a dozen fusion startups have now raised over $100 million each, highlighting how investor enthusiasm continues to fuel rapid experimentation despite the long road to scalability.

Lowercarbon’s continued interest reflects a growing consensus that private capital will play a crucial role in making fusion commercially viable — even as timelines for achieving “net energy gain” remain uncertain.

The Bigger Picture

Fusion energy — the process that powers the sun — has long been seen as the “holy grail” of clean power due to its potential to provide abundant, carbon-free electricity without the long-lived radioactive waste of traditional nuclear fission.

Sacca’s firm, which has built a reputation for bold bets in climate technology and carbon removal, appears committed to keeping fusion on its investment agenda.

With the new fund, Lowercarbon Capital aims to back the next wave of companies working to turn scientific promise into scalable energy production, even as the sector’s costs, complexity, and competition continue to climb.