The brief
- Uses electricity to pull calcium from rock without burning limestone, avoiding both fuel and rock CO2.
- DOE cancelled its $87M award in May 2025; Holyoke was paused in December 2025 and about two-thirds of staff were later cut.
- Signed a deal in 2025 for Microsoft to buy its cement.
Technical approach
Chemistry
Electricity instead of a kiln
An electrolyser makes acid and base. The acid dissolves calcium from non-limestone rock, which becomes cement, with no rock CO2 released.
Programs
Sublime Systems, one program
Updated 1 Dec 2025
Research · Proto · Pilot · Deploy · Scaling
Open technical problems
- Funding the first plantsOpen
Without government support, raising money for the first plants of a new cement process is very hard.
Peers
Company & funding
- HQ
- US
- Founded
- 2020
Partners & customers
- Customer
Agreed to buy its low-carbon cement (2025).
People
- Leah EllisCo-founder & CEO
- Yet-Ming ChiangCo-founder