Commonwealth Fusion Systems leads the over $100M fusion startup cohort

Fusion power has transitioned from a skeptical industry to a tangible technology attracting significant investor interest. This bullish wave buoying the fusion industry has been driven by more powerful computer chips, more sophisticated AI, and powerful high-temperature superconducting magnets. These technological advancements have enabled a cohort of fusion startups to secure over $100M in funding as they attempt to harness the nuclear reaction that powers the sun to generate nearly limitless energy here on Earth.

Massachusetts-based Commonwealth Fusion Systems (CFS) stands out as a leader in this cohort. The company has raised near $3 billion in total private capital, a sum that includes an $863 million latest funding round. CFS is currently building Sparc, its power plant in Massachusetts. The startup expects to have Sparc operational in late 2026, aiming to produce power at what it calls “commercially relevant” levels. Sparc utilizes a tokamak design—a doughnut-shaped fusion reactor—wound with high-temperature superconducting tape to contain and compress superheated plasma. If successful, CFS plans to build its commercial power plant, Arc, near Richmond, Virginia.

Beyond CFS, the broader fusion landscape in the U.S., British Columbia, Germany, and the U.K. features a diverse array of startups pursuing distinct technical approaches to achieve commercial viability. Each of these companies has raised over $100M to fund their development:

• TAE Technologies: Pursues a field-reversed configuration, using particle beams to stabilize plasma.
• Helion: Based in Everett, Washington, Helion uses a field-reversed configuration to collide plasma and harvest electricity directly.
• Pacific Fusion: Employs inertial confinement—a fusion approach using compression to ignite fuel—relying on coordinated electromagnetic pulses rather than lasers.
• General Fusion: Based in Richmond, British Columbia, the company uses magnetized target fusion, compressing plasma inside a liquid metal wall.
• Type One Energy: Building a stellarator—a twisted magnetic confinement fusion reactor design—on the site of a retired coal plant in Tennessee.
• Tokamak Energy: Located in Oxfordshire, U.K., the company is developing a spherical tokamak design.
• Focused Energy & Proxima Fusion: Operating in Germany, these startups are developing laser-driven inertial confinement and stellarator designs, respectively.
• Other over $100M startups: The cohort also includes Shine Technologies, Inertia Enterprises, Zap Energy, Kyoto Fusioneering, Marvel Fusion, Thea Energy, First Light Fusion, and Xcimer, each developing specialized reactor designs or balance of plant components.

Why it matters

Fusion power has transitioned from a skeptical industry to a tangible technology attracting significant investor interest, potentially upending trillion-dollar markets if commercially viable plants are achieved.