Commonwealth Fusion Systems (CFS) is an MIT-spinout fusion-energy company founded in 2018 that is building SPARC, a demonstration tokamak, en route to ARC, a planned grid-scale fusion power plant.
Commonwealth Fusion Systems spun out of the 📝Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center in 2018 and is headquartered in Devens, Massachusetts. Its approach to 📝fusion power centers on high-temperature superconducting (HTS) magnets, which produce strong magnetic fields that allow a smaller, lower-cost tokamak than earlier designs. In 2021 the company demonstrated a 20-tesla HTS magnet, the milestone underpinning its reactor program.
The company is building SPARC, a demonstration tokamak in Devens designed to prove net energy gain — producing more power than it consumes (Q greater than 1). SPARC is scheduled to begin operations in 2026 and to demonstrate net power in 2027. Its first commercial plant, ARC, is planned for Chesterfield County, Virginia, near Richmond — a roughly 400-megawatt grid-scale plant targeted to reach the grid in the early 2030s, supported by partnerships with Dominion Energy and Google.
CFS has raised close to $3 billion, roughly a third of all private capital invested in fusion worldwide, including an $863 million Series B2 round in August 2025 backed by Nvidia, Google, and others. It has also participated in the U.S. Department of Energy's INFUSE public-private innovation program alongside national labs and universities, and is widely regarded as a frontrunner in the race to commercialize fusion energy.
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