Commonwealth Fusion Systems
Bob Mumgaard
Overview
Commonwealth Fusion Systems is building commercial fusion systems around high-temperature superconducting magnet technology developed with MIT. SPARC is its fusion-energy demonstration tokamak under construction in Devens, Massachusetts, and ARC is its planned first commercial plant designed to bring hundreds of megawatts of fusion power to the grid in the early 2030s. CFS also manufactures HTS magnets as the enabling technology behind its compact, high-field tokamak approach.
Main Products
Compact, high-field tokamak designed to demonstrate net energy from fusion. It uses high-temperature superconducting magnets to achieve reactor-class magnetic fields in a much smaller machine, with peer-reviewed projections of roughly Q ~11 and ~140 MW of fusion power.
Assembly is advancing at the Devens campus. As of April 2026, CFS says the facility is about 75% complete, with both halves of the vacuum vessel and two of the 18 toroidal field magnets in Tokamak Hall.
CFS' first planned grid-scale commercial fusion power plant, designed to deliver about 400 MW of clean electricity using the HTS magnet and tokamak stack proven through SPARC.
Site selected at James River Industrial Center in Chesterfield County, Virginia. CFS said in April 2026 that it has not yet broken ground, while first operation remains targeted for the early 2030s.
What's Next
Operations & Revenue
Development stage — SPARC remains under construction and ARC has not yet broken ground, but CFS is beginning to commercialize its HTS magnet platform through external supply and licensing partnerships.