Nuclear fusion company raises $1B, partly slated for Chesterfield

Massachusetts-based fusion energy company Commonwealth Fusion Systems, which plans to build the world’s first grid-scale commercial nuclear fusion power plant in Chesterfield County, announced Thursday it raised $1 billion in additional equity financing.

“That really puts us in a position here where we can go quickly, we can go at scale, we can go at a level that is, frankly, what is needed to make fusion advance as quickly as we’d like it to advance,” CFS CEO and co-founder Bob Mumgaard said during a media briefing.

CFS will use some of the funds to progress development on the 400-megawatt fusion power plant in Chesterfield, dubbed ARC, which is expected to be in operation in the 2030s. It’s slated to be built on a roughly 94-acre property at 1201 Battery Brooke Parkway in the James River Industrial Center.

The capital raise is the single-largest funding round among fusion energy companies worldwide since CFS announced a $1.8 billion Series B round in 2021, according to a news release. In 2025, it raised $863 million in a Series B2 round. With this capital, CFS has now raised a total of $4 billion, which represents about 30% of the total capital raised by the fusion industry to date.

Spun out of MIT in 2018, CFS is one of more than 50 companies currently pursuing fusion technologies. The company is building a fusion demonstration machine, nicknamed SPARC, at its headquarters in Massachusetts. It’s about 80% complete, according to Mumgaard.

CFS regularly welcomes investors to tour the facility where it’s being built. “This gives them confidence, confidence in us that’s justified,” Mumgaard said.

CFS will use the money raised to speed commercialization. In addition to completing the assembly of SPARC, CFS “continues to move forward” with the development of ARC in Chesterfield.

“This new funding puts us in a position to move at scale and as quickly as we need to deliver fusion energy,” Mumgaard wrote in a LinkedIn post Thursday. “We’ll be able to apply what we’ve already learned from SPARC to build at-scale prototypes of other technology we need, retool our supply chain, expand our manufacturing, prepare the site for our first ARC power plant, and start contracting power for the next plants.”

The funding will allow CFS to move forward with design development on ARC, according to CFS spokesperson Christine Dunn. She declined to disclose the cost of the project. When it was announced in December 2024, Garrett Hart, Chesterfield’s economic development director, said the plant would likely cost more than $2.5 billion.

SPARC uses 13 of the 17 subsystems the Chesterfield plant requires, according to CFS. Specifically, the ARC facility will require the development of a heat capture and turbine-related systems “that allow us to generate electricity and put it on the grid,” Dunn wrote in a statement Friday. 

“Where we’re at now is we’re getting ready to move some dirt down there and start to prep that site,” Mumgaard said. “Not announcing exactly when we’ll do that, but that’s the next big sequence on that site: Actually moving toward construction.”

Investors in the additional raise included pension funds, sovereign wealth funds, infrastructure investors and industrial corporate partners, according to CFS. The company declined to disclose investors.

“This is a new class of capital that you’re seeing into the CFS capital stack,” Mumgaard said. “I think [this] is a really good sign about the progress that we’re making as a company and also the ascendance of fusion as a field.”

California-based tech giant Google has invested in the nuclear fusion company since 2021. Italy’s Eni, a global energy tech company, was among the first to invest in CFS in 2018. The two companies have signed agreements to purchase more than half of the power the Chesterfield County plant will produce.

Other high-profile CFS investors include Jeff Bezos, Bill Gates, Tiger Global Management and Khosla Ventures.

In April, CFS announced it was the first fusion company to submit an application to PJM Interconnection, a regional transmission organization that manages the electric grid in all or parts of 13 states and Washington, D.C.

In 2024, CFS announced it had reached an agreement with Dominion Energy Virginia for the utility to provide nonfinancial collaboration, such as development and technical expertise, as well as leasing rights at James River Industrial Center, where ARC will be located.

“If you think about us standing on two feet, the weight is shifting from the SPARC foot to the ARC foot,” Mumgaard said. “And that’s super exciting because it means that when SPARC turns on, we’ll be
able to take off on the next step to ARC.”