Commonwealth Fusion Systems
United States · Devens, MAFounded 2018Plant developerFF001
Company-stated design point, no independent validation
Data confidence: High
Overview
- Confinement
- Tokamak
- Fuel cycle
- D-T
- Development stage
- Demo under construction
- Key milestone
- SPARC first plasma targeted 2026; net-energy (Q>1) attempt 2027
- Target first commercial power
- Early 2030s
- Notes
- Largest-funded private fusion company globally; first to enter a major grid interconnection queue.
Design point
- Design net power
- 400 MWMWe (design target, ARC)
- Reactor island volume
- PENDING
- Time-averaged power density
- —pending volume
- Evidence grade
- E4
- Grade rationale
- ARC design target is company-stated; SPARC has not yet demonstrated net energy.
Funding
- Lifetime funding
- US$ 3,000M
- Latest round
- $863M Series B2, Aug 2025
- Key investors
- Breakthrough Energy Ventures, Google, NVIDIA, Temasek, Eni, Khosla
Siting
- Flagship site
- Fall Line Fusion Power Station, Chesterfield County, VA
- Siting status
- Named site; PJM interconnection application filed Apr 2026
- Offtake / PPA
- Google 200MW offtake; Eni PPA (>$1bn reported)
Grid fit
The metric set that maps onto ex-battery sites. Pending cells are open questions for the company.
- As of
- August 9, 2026Medium
- Footprint (ha, FOAK)
- PENDING
- Cooling type
- Water (thermal/steam cycle, expected)
- Grid connection class
- Transmission — PJM interconnection queue application filed
- Startup import load
- PENDING
- Conversion type
- Thermal (steam cycle)
- Ramp capability
- PENDING
- Notes
- Site is a former industrial park (James River Industrial Park); footprint not yet publicly quantified.
Sources
As listed in the Phase-0 Master Index; URLs to be added during right-of-reply.
- CFS press releasescompany_primary · Company press release
- World Nuclear News, Apr 2026trade_news · World Nuclear News
- Bloomberg, Apr 2026tier1_news · Bloomberg
As of: August 9, 2026