Commonwealth Fusion Systems keeps proving that people are eager to throw money at the possibility of nuclear fusion. The startup raised a $863 million Series B2 round, it announced this week.
The top-up follows the company’s $1.8 billion Series B in 2021, which was among the largest energy and climate tech raises of all time. To date, the company has raised close to $3 billion.
In this latest oversubscribed round, the company brought on new investors, including NVentures, Nvidia’s venture capital arm. CFS’ sources of financing include venture capital, private equity, sovereign wealth funds, industrials, and others. Individual investors include both Bill Gates and Jeff Bezos.
The MIT spinoff plans to use the funds to complete its fusion demonstration machine, known as SPARC, as well as its first commercial-scale plant, known as ARC, in Virginia. The latter, announced in 2024, is in partnership with Dominion Energy, the utility serving Virginia’s so-called Data Center Alley.
The 400-megawatt facility is planned for the early 2030s, though the timeline of the plan — and its realization at all — depends on achieving continuous fusion, a milestone that has not yet been reached by CFS or anyone else. CCO Rick Needham told Latitude Media that the company evaluated hundreds of sites over two years before settling on the location in Chesterfield, south of Richmond.
While CFS has raised the most money and is the only company with a commercial agreement, the technology itself remains a work in progress. In 2022, a lab at Lawrence Livermore National Laboratory managed to break even on energy for fusion ignition — a major proof point. Now, startups including CFS are working to show that it’s possible to create reactions that produce more energy than they consume.
CFS said in 2024 that their technology should start producing energy sometime after 2026, “demonstrating for the first time a commercially relevant design that will produce more power than consumed.”
If CFS indeed is the one to make it happen, the promise of nearly limitless clean power would be transformative, especially for the many tech companies and industrials competing for electricity in an era of unexpected load growth. And those potential beneficiaries are already lining up behind CFS; in addition to the support of Bezos, Gates, and others, the company signed a strategic partnership with Google in June. The company’s first commercial commitment to fusion is an offtake agreement for 200 MW of fusion from the ARC power plant.
Actually getting to the point where CFS has power to sell will take enormous capital and technical expertise, as well as new supply chains. But the company is on its way to wrangling all of those necessary inputs.
As Needham said on a live recording of the Green Blueprint podcast at the Transition-AI conference in June, CFS needed thousands of kilometers of high-temperature superconducting tape that barely existed, it had to create the infrastructure to produce it at the quantities it needed almost from scratch.
The tape is wound in a circle to become “the biggest, strongest, most powerful magnet in the world,” Needham explained. And while it took the company about six months to get the first “pancake” made, CFS is “now spitting out one a day,” Needham said, describing the learning curve that will be crucial for cost reduction. “We’re on very rapid cost down curves.”
Whether CFS can eventually compete economically with other power sources will depend in part on this manufacturing efficiency. The company anticipates that it can reach $50 per megawatt-hour through economies of scale in both tape production and magnet manufacturing. That would be competitive with wind and solar — with the added advantage of being a clean firm source of power.
Listen to Rick Needham’s whole interview on The Green Blueprint:
