Commonwealth Fusion Systems
Category: AI in Climate / Energy
Commonwealth Fusion Systems (CFS) is developing compact, high-field tokamaks using high-temperature superconducting (HTS) magnets to generate clean, limitless, and commercially viable fusion energy. Commonwealth Fusion Systems was founded in 2018. The company is led by Bob Mumgaard. Based in Devens, Massachusetts, United States. Team size: 1001-5000. Total funding raised: $2.9 billion. Latest round: Series B2, $863.0M, 2025-08, led by Undisclosed. Key investors include Tiger Global Management, Breakthrough Energy Ventures, Google, Bill Gates, Temasek, Khosla Ventures, Eni, Coatue, Emerson Collective, Eric Schmidt.
- Founded
- 2018
- Headquarters
- Devens, Massachusetts, United States
- Team size
- 1001-5000
- Total funding
- $2.9 billion
Value proposition
To provide a scalable, carbon-free, safe, and limitless energy source to combat climate change by commercializing fusion power on a faster timeline and at a lower cost than previously possible.
Products and solutions
SPARC: A compact, high-field, net-energy-gain tokamak demonstration device., ARC: The first commercial fusion power plant designed to deliver electricity to the grid., High-Temperature Superconducting (HTS) Magnets: The core enabling technology that allows for smaller and more powerful fusion devices.
Unique value
The company's uniqueness lies in its use of high-temperature superconducting (HTS) magnets. This technology allows for the creation of a much stronger magnetic field, which in turn enables the construction of significantly smaller, more efficient, and cost-effective tokamak fusion devices compared to traditional, larger-scale projects.
Target customer
The primary target customers are electric utilities, independent power producers, and large industrial consumers that require reliable, carbon-free, baseload power.
Industries served
Energy, Utilities, Power Generation
Technology advantage
CFS's key technological advantage is its proprietary HTS magnet technology, which enables a faster and more commercially viable path to fusion energy. Their business advantage stems from their origin as a spin-out from MIT's Plasma Science and Fusion Center, providing a strong foundation of scientific research, credibility, and talent. This is coupled with substantial private funding from major investors, giving them a significant capital advantage.
How they differentiate
CFS differentiates itself through its use of high-temperature superconducting (HTS) magnets, which allows for the creation of smaller, more powerful, and commercially viable fusion systems. This approach, based on the ARC tokamak design, is aimed at providing a faster and more cost-effective path to commercial fusion energy.
Main competitors
Helion Energy, TAE Technologies, General Fusion
Key partnerships
Massachusetts Institute of Technology (MIT): CFS was spun out of MIT and maintains a deep, ongoing research and collaboration agreement., Breakthrough Energy Ventures: An early and significant investor founded by Bill Gates., Google: A strategic partner and investor, collaborating on computational modeling and AI. Signed 200MW PPA for ARC power plant (Jul 2025)., Nvidia: An investor providing computational resources and expertise. Collaborating on AI-powered digital twin of SPARC (Jan 2026)., Eni: An Italian energy company and a strategic investor. Signed $1B+ PPA for ARC power (Sep 2025)., Siemens: Collaborating on AI-powered digital twin of SPARC using Siemens Xcelerator portfolio (Jan 2026)., Dominion Energy: Joint Development Agreement providing development/technical expertise for ARC power plant in Virginia (2024-2025)., Realta Fusion: Long-term strategic partnership to design/build HTS magnets for Realta's fusion systems., Type One Energy: Licensed CFS' HTS cable technology for stellarator fusion magnets.
Notable customers
Google, Eni
Major milestones
Successful demonstration of a large-scale high-temperature superconducting (HTS) magnet, a key component for their compact fusion device., Construction of the SPARC project, a compact, high-field, net fusion energy gain tokamak, in collaboration with MIT., First of 18 SPARC superconducting magnets installed (Jan 2026)., Google signed 200MW PPA for ARC power plant (Jul 2025)., Eni signed $1B+ PPA for ARC power (Sep 2025)., Secured world's first Conditional Use Permit for a commercial fusion power plant (2025)., Filed first-ever fusion plant interconnection application with PJM grid operator (Apr 2026)., Announced AI-powered digital twin collaboration with NVIDIA and Siemens (Jan 2026).
Growth metrics
As a private company, specific growth metrics are not publicly available.
Market positioning
CFS is a leader in the private fusion energy sector, leveraging its MIT origins and substantial funding to accelerate the commercialization of fusion power. The company is positioned as a key player in the race to develop a practical and scalable clean energy source.
Geographic focus
While CFS is based in the United States (Devens, Massachusetts) and its primary development activities are centered there, its long-term vision is global, aiming to deploy its fusion power plants worldwide to address the global demand for clean energy.
Patents and IP
While specific patent numbers are not detailed in public-facing documents, CB Insights reports that the company has filed at least 24 patents. The company also validates its technological progress through peer-reviewed scientific publications, including a series of seven papers in the Journal of Plasma Physics.
About Bob Mumgaard
Co-founder and CEO of Commonwealth Fusion Systems. Previously, he worked on the design of several small superconducting tokamaks during his PhD at MIT's Plasma Science and Fusion Center.
Official website: https://cfs.energy/