Among the eight fusion startup companies that will share $46 million in grants to help build commercial power plants are four that are pursuing approaches—stellarator, magnetic mirror, and Z pinch—that were once major programs in Department of Energy labs before being mostly abandoned in favor of tokamaks.

Awardees also include two companies that are pursuing differing approaches to inertial fusion. Two others are developing tokamaks.

DOE says the grants will assist the companies to develop their respective designs for commercial fusion pilot plants in 5–10 years. At least one recipient, the MIT spin-off Commonwealth Fusion Systems, has said it will begin constructing a pilot power plant within five years. It has raised more than $2 billion. The well-established Cambridge University spin-off Tokamak Energy has been working on its spherical tokamak design for more than a decade in the UK. Officially, its award went to a US subsidiary in West Virginia....

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