What happens when a bunch of MIT fusion scientists take their lab coats off, lace up startup boots, and step into the energy ring swinging? You get Commonwealth Fusion Systems, a company not just talking about limitless clean power, but building it, wiring it, and selling it in megawatts.
On June 30, 2025, CFS quietly turned up the voltage. Another Series C round just landed, with Google stepping in not just as an investor, but as a buyer, signing a 200MW power purchase agreement for the inaugural ARC plant in Chesterfield County, Virginia. That’s not a handshake, that’s a 9-figure vote of confidence in a future still waiting for most of the industry to catch up.
This isn’t your typical “climate tech” headline. This is fusion. That word everyone throws around like it’s still 30 years away. CFS is out here saying 2030s, not 2080s. Saying 400 megawatts from a compact fusion reactor, not a pipe dream buried in a whitepaper. That’s not speculation, that’s SPARC, the demonstration reactor set to hit net energy gain (Q>1) by 2027, already more than halfway built. And ARC? That’s not a science project. That’s a commercial plant with permits moving, steel being planned, and demand knocking.
Let’s give credit where it’s overdue, Bob Mumgaard, co-founder and CEO, leads with a PhD and a chip on his shoulder about the timeline to fusion. Brandon Sorbom, co-founder and Chief Science Officer, is the mind behind the high-temperature superconducting (HTS) magnet tech that flipped the scale problem upside down. Dan Brunner (former CTO), Zach Hartwig, Martin Greenwald, Dennis Whyte, each came from MIT’s Plasma Science & Fusion Center and rewrote how fusion could get built, fast and at scale. This wasn’t born in a boardroom, it was born in a classroom that refused to follow old rules.
CFS has now raised over $2.8B, backed by the heaviest hitters in climate capital, Breakthrough Energy Ventures, Tiger Global, Temasek, Equinor, Khosla Ventures, Soros Fund Management, Jeff Bezos, John Doerr, Marc Benioff’s TIME Ventures, and now, once again, Google, not just betting, but buying.
With over 1,000 employees scaling magnet production, finalizing SPARC, and breaking ground for ARC, CFS isn’t waiting for public policy or industry consensus. They’re building the product that powers the grid, and selling to the customers who need it most, data centers, industrials, hyperscalers. This is the power business, with physics as the product and time as the enemy.
Most clean tech plays are hedges. CFS is all-in. And if this works, and let’s be clear, it’s already working, the game changes, and so does the grid. You don’t bet against a team that’s already building the future and selling the electricity before the lights are even on.
