Commonwealth Fusion Systems last week announced that a recent financing round had raised $1.8 billion in capital, making the company far and away the funding leader among a host of commercial fusion rivals. The previous leader, TAE Technologies, has announced investments totaling $880 million.
Commonwealth, which spun off from research at MIT, says the new investments will finance the construction, commissioning, and operation of its demonstration reactor, called SPARC. In 2018 Commonwealth estimated SPARC would cost $400 million. The funds will also pay for design and other preliminary work on a planned commercial fusion energy plant. Commonwealth has now raised a total of $2 billion since its founding in 2018.
The news follows the successful performance in September of Commonwealth’s full-scale prototype magnet. Made with yttrium barium copper oxide coils, the magnet exceeded 20 tesla, which the company says is the highest field ever recorded in a magnet made with high-temperature superconductors. The prototype is similar in size and construction to the 18 torroidal field magnets that will be components of SPARC, which is under construction in Devens, Massachusetts. The company predicts SPARC will achieve net fusion power in deuterium–tritium fuel in 2025.
But Daniel Jassby, a retired physicist from the Princeton Plasma Physics Laboratory (PPPL), the US flagship fusion research lab, says Commonwealth’s investors “are being grossly misled about the time scales required.” PPPL’s Tokamak Fusion Test Reactor and the UK’s Joint European Torus, the only two fusion reactors in the world to have used tritium, did so only after 10 years of experimenting with hydrogen and deuterium alone. Even if that warm-up period could be halved, SPARC’s tritium operation wouldn’t be likely to occur before 2032, Jassby says. Assuming SPARC is a success, it will take many more years for Commonwealth to develop the other technologies needed for a commercially attractive power source, he adds.
Should it succeed by mid-decade in producing more fusion energy than required to initiate and sustain the reaction, Commonwealth would beat ITER, the seven-member international fusion collaboration, to that milestone by at least 10 years. Although ITER is expected to begin experiments with deuterium plasmas in 2025, tritium operation—a prerequisite for producing net energy—isn’t due until 2035. The company says SPARC’s high fields should allow it to be one-tenth the size of ITER, whose low-temperature superconducting magnets are designed to yield 12 tesla (see Physics Today, August 2018, page 25).
Commonwealth’s new investors include Bill Gates and other wealthy individuals, a veritable who’s who of venture capital and private equity firms, Google, an unnamed university endowment, and a pension plan. A long list of previous contributors, including Italian oil company Eni, Breakthrough Energy Ventures, MIT’s startup incubator The Engine, and other individuals and investment funds, also upped their investments.
Michl Binderbauer, CEO of TAE Technologies (see Physics Today, February 2019, page 28), acknowledges that Commonwealth has for now surpassed his company in fundraising, yet he says a TAE financing round expected to close early in 2022 will add “a considerable figure to our tally.” Commonwealth’s announcement “is very exciting news for the entire fusion community,” he says, and it will help “make fusion move out of the realm of ‘maybe in 30 years’ to something that institutional investors can get behind as they can see it coming much sooner.”
