Commonwealth Fusion Systems raises $863M from Nvidia, Google, and Bill Gates

Massachusetts-based Commonwealth Fusion Systems (CFS) has secured $863 million in fresh funding, drawing support from an impressive roster of backers including Nvidia, Google, Breakthrough Energy Ventures, and a long list of venture and institutional investors. The raise marks another milestone for the most heavily funded fusion startup, pushing its total haul to nearly $3 billion.

“We’re continuing our trend here of looking into the world and saying, ‘How do we advance fusion as fast as possible?’” said co-founder and CEO Bob Mumgaard in a press call. “This round of capital isn’t just about fusion as a concept, but about how we turn it into a commercial industrial endeavor.”

Fusion’s Promise and CFS’s Roadmap

Fusion energy—long heralded as a near-limitless, clean power source—has historically been seen as more dream than reality. But recent advances in supercomputing, materials science, and AI-driven modeling have accelerated progress, igniting a surge of investment in the sector.

At its core, fusion involves heating and compressing atoms into plasma, a fourth state of matter. When conditions are right, atomic nuclei fuse, releasing massive amounts of energy without the long-lived radioactive waste associated with fission.

CFS is betting big on its tokamak-based designs, which use powerful superconducting magnets to contain plasma. The company is currently constructing its Sparc prototype reactor near Boston, with plans to switch it on late next year. The goal: reach scientific breakeven by 2027, producing more energy from fusion reactions than is required to sustain them.

While Sparc won’t supply power to the grid, it’s a crucial step toward commercialization. If successful, it will clear the path for Arc, CFS’s planned full-scale fusion power plant in Virginia, targeted for construction starting in 2027 or 2028.

Investor Confidence and Strategic Partnerships

CFS’s latest funding round saw no single lead investor. Instead, a wide range of existing supporters increased their stakes, including Breakthrough Energy Ventures, Google, Khosla Ventures, Lowercarbon Capital, Tiger Global, and former Google CEO Eric Schmidt.

New backers include Morgan Stanley’s Counterpoint Global, Brevan Howard, Stanley Druckenmiller, Galaxy Interactive, Nvidia’s NVentures, and a consortium of Japanese companies led by Mitsui & Co. and Mitsubishi Corporation.

This diverse investor base could prove invaluable as CFS scales up, helping it establish supply chains, attract industrial partners, and secure long-term electricity buyers. Notably, the company has already signed a deal with Google to purchase 200 megawatts from its first Arc plant.

Challenges Ahead

Despite the momentum, experts caution that much remains uncertain. “It’s always an open question when you turn on a completely new device that it might go into plasma regimes we’ve never been into,” said Saskia Mordijk, a physics professor at William & Mary. “The question is naturally, how will it perform?”

CFS acknowledges the hurdles. While Sparc’s success would validate the science, Mumgaard emphasized that it’s equally about proving cost models, engineering capabilities, and supply chain readiness. Arc, as a first-of-its-kind facility, is expected to cost several billion dollars—funding that has yet to be secured.

“The fact that it’s a first-of-a-kind technology is a wrinkle that has a big impact on where the capital will come from,” Mumgaard noted. “We’re not entirely sure, but we are pretty committed to doing this. And our investors are pretty committed to doing this.”

The Bigger Picture

Fusion startups worldwide are racing to cross the breakeven threshold and move toward commercialization, with CFS now holding the fundraising lead. If Sparc delivers on its promise, it could place the company at the forefront of a new energy era.

For now, investors and scientists alike are watching closely—hoping that CFS can turn decades of fusion dreams into commercial reality.