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Commonwealth Fusion Systems raises $110 million

MIT spin-off says new magnet design paves way for smaller, cheaper reactor

by Melody M. Bomgardner
July 3, 2019 | A version of this story appeared in Volume 97, Issue 27


This image shows a computer rendering of Commonwealth Fusion System's small tokamak fusion reactor.
Credit: Commonwealth Fusion Systems
This computer generated image shows the small tokamak fusion reactor that CFS plans to build by 2025.

Commonwealth Fusion Systems, a start-up aiming to commercialize a new fusion energy reactor, has raised $110 million in a first round of funding from the Italian energy company Eni and venture funds backed by Silicon Valley billionaires including Bill Gates, Vinod Khosla, and Jeff Bezos.

A spin-off of the Massachusetts Institute of Technology, CFS is collaborating with MIT’s Plasma Science and Fusion Center to develop its reactor. The company’s first goal is to produce a new type of high-temperature superconducting magnet made from rare earth–barium–copper oxide. The compact magnet will help it build a small, low-cost tokamak-style reactor, CFS claims.

Tokamak reactors use strong magnetic fields to contain unstable high-temperature plasma inside of a doughnut-shaped device. Inside the plasma, deuterium and tritium atoms fuse, releasing energy. Tokamak reactors are typically large and expensive because they rely on bulky, supercooled magnets kept as cold as 4 K.

Fusion companies such as Tri Alpha Energy, Helion, General Fusion, and Tokamak Energy have attracted private investors for at least 20 years. But “Commonwealth just thrust itself on the stage and has had a very impressive debut,” says Malcolm Handley, managing partner of Strong Atomics, a fusion-focused venture firm.

Firms with smaller reactors can move more swiftly than big, government-backed collaborations, Handley says. CFS plans to use the magnets to build its first reactor and demonstrate net energy gain by 2025.

Fusion firms have proliferated since 2015, thanks to funding from the US Department of Energy’s Advanced Research Projects Agency-Energy (ARPA-E) program. The field has also received a boost from investors like Gates who are funding technologies that combat climate change.



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