Clean energy journalism for a cooler tomorrow

Commonwealth Fusion pulls in a colossal $1.8B for novel nuclear tech

Billionaires and VCs continue to invest fortunes in fusion companies, despite distant prospects of success.
By Eric Wesoff

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The SPARC tokamak (Commonwealth Fusion)

This week’s behemoth $1.8 billion investment in nuclear fusion startup Commonwealth Fusion Systems vastly outsizes last month’s behemoth $500 million investment in nuclear fusion startup Helion Energy.

Almost $4 billion has recently been channeled toward commercializing nuclear fusion from scores of private-capital sources. You’d be hard-pressed to find a climatetech venture capitalist who hasn’t closed on or at least considered an investment in this long-promised and highly speculative technology. (Canary Media surveyed the landscape of fusion technologies, investors and players in this recent roundup.)

Tiger Global Management led this funding round for Commonwealth Fusion Systems (CFS), bringing in money from a phalanx of once-sane venture capitalists and billionaires. New investors include (in alphabetical order): Bill Gates; Coatue; DFJ Growth; Emerson Collective; FootPrint Coalition; Google; Jimco Technology Fund, which is part of Jimco, the Jameel family’s global investment arm; John Doerr; JS Capital; Marc Benioff’s Time Ventures; Senator Investment Group; a major university endowment; and a pension plan.

Previous investors also joined this round, including Breakthrough Energy Ventures; The Engine; Eni; Equinor Ventures; Fine Structure Ventures; Future Ventures; Hostplus; Khosla Ventures; Lowercarbon Capital; Moore Strategic Ventures; Safar Partners; Schooner Capital; Soros Fund Management LLC; Starlight Ventures; and Temasek.


The nuclear fusion funding ecosystem runs on milestones, not actual fusion, and it’s these deep engineering breakthroughs that are driving the fusion finance flurry.

CFS is a company that executes — making possible what seemed impossible, one technical milestone at a time,” said John Doerr, chair of Kleiner Perkins, in a release.

The most recent milestone for CFS is a breakthrough in an enabling technology: high-temperature superconducting magnets. In September, in collaboration with MIT, CFS built and demonstrated high-temperature superconducting magnets that are claimed to be the strongest of their kind and a key technological win in the process of commercializing fusion energy.

CFS hitting this magnet milestone is what precipitated the recent massive funding tranche.

Magnetic confinement fusion, as used by CFS, has remained the status quo of fusion research methods for 60 years. It uses massive, expensive, cooled magnetic coil structures to confine and stabilize plasma during the reaction. The most frequently deployed scheme uses a vessel shaped like a hollow doughnut, called a tokamak, in which the magnetic field forms a closed loop.

Commonwealth’s stride in magnet performance could enable the development of compact fusion power plants that can be constructed faster and at lower cost than other proposed fusion (or nuclear fission) plant designs. The high-temperature superconducting magnets are made with a rare-earth material that is deposited in a thin-film process on a tape-like stainless steel band. It is a technology still in development and one that lacks a mature supply chain.

Deconfusing fusion

Here are some fusion basics.

When heated to tens of millions degrees Celsius, hydrogen changes from a gas to a plasma in which negatively charged electrons are separated from positively charged atomic nuclei. Plasma is considered to be the fourth state of matter, and it’s the medium in which fusion occurs.

Fusion machines compress and confine the plasma in order to bring nuclei so close together as to overcome repellant electrostatic forces and allow the nuclei to fuse. Fusion occurs by virtue of the strong nuclear force and yields helium and energy in the form of neutrons.

Neutrons generated from a fusion reaction would be absorbed in a molten salt or metal surrounding the core. Heat energy collected from the molten material could be used to drive a conventional turbine.

The fundamental challenge is to achieve a rate of heat emitted by a fusion plasma that exceeds the rate of energy injected into the plasma,” according to the World Nuclear Association.

Proponents claim that fusion energy, if harnessed, would have none of the proliferation or meltdown risks associated with nuclear fission. While fusion does create less radioactive waste than fission, it certainly comes with its own set of risks related to radioactive byproducts, as well as proliferation and societal health risks.

Promises, promises

The high stakes of venture-capital investing, along with the threat of a climate-based extinction event, have forced fusion startup CEOs to make some aggressive timeline commitments.

TAE Technologies, another fusion company that’s been raising hundreds of millions of dollars from big-name investors, expects commercialization of its fusion power plants to begin in the late 2020s. Helion plans to build the first fusion device capable of demonstrating net electricity production by 2024. Commonwealth claims it will achieve commercially relevant net energy” from fusion in 2025 and complete construction of its first fusion power plant in the early 2030s.

Eric Wesoff is the executive director at Canary Media.