The archive · Climate & Energy · Product decision · 2024–2025
Fortera: bolt-on captures kiln CO2 and turns it into low-carbon cement
A bolt-on captures a cement kiln's waste CO2 and mineralizes it into low-carbon cement — proven at Redding, now funded by Microsoft toward 400,000 tons a year.
Fortera
What the business is
Fortera is a materials technology company whose ReCarb process bolts onto an existing cement plant: it draws CO2 from the kiln flue-gas stack and mineralizes the gas into ReAct, a low-carbon calcium-carbonate cement that can be blended with or replace ordinary Portland cement. ReCarb cuts CO2 by about 70% ton-for-ton, runs the kiln cooler, and converts waste gas into additional product instead of releasing it.
How it started
Cement production accounts for roughly 8% of global CO2, and most of it is chemical: when limestone is heated in a kiln, nearly half the feedstock is lost as CO2. Fortera's answer, built on more than a decade of testing and over 100,000 hours of research, was not a new kind of kiln but a bolt-on — capture flue-gas CO2 and mineralize it into ASTM-approved ReAct cement, usable on its own or blended.
What happened
On April 12, 2024 Fortera opened its Redding ReCarb Plant beside CalPortland's cement works in Redding, California — billed as the first industrial green-cement and carbon-mineralization facility in North America. It captures 6,600 tons of CO2 a year and produces 15,000 tons of ReAct, cutting emissions about 70% ton-for-ton at a kiln temperature of 1,100°C rather than 1,450°C. On September 23, 2025 Microsoft's Climate Innovation Fund invested to help build a 400,000-ton-per-year facility and took procurement rights to ReAct plus environmental attribute certificates.
How it ended up
Still scaling: as of late September 2025 Fortera operates the 15,000-ton Redding plant, has placed ReAct in real construction projects, and holds Microsoft funding plus an anchor customer for its first 400,000-ton-per-year commercial facility.
Background
Cement production emits roughly 8% of global CO2, and most of that is chemical: heating limestone in a kiln releases nearly half the feedstock as CO2. Fortera spent more than a decade and 100,000 hours of research on a different answer — not a new kiln, but a bolt-on called ReCarb that captures flue-gas CO2 and mineralizes it into ReAct, an ASTM-approved low-carbon cement that can be blended with or replace ordinary Portland cement.
In April 2024 Fortera opened the Redding ReCarb Plant beside CalPortland's cement works in California, calling it the first industrial green-cement and carbon-mineralization facility in North America. The plant captures 6,600 tons of CO2 a year from CalPortland's flue, produces 15,000 tons of ReAct annually, cuts emissions about 70% ton-for-ton, and runs at 1,100°C instead of the usual 1,450°C.
On September 23, 2025 Microsoft's Climate Innovation Fund invested to support Fortera's first full-scale 400,000-ton-per-year facility. Microsoft secured procurement rights to ReAct and environmental attribute certificates to count against its Scope-3 emissions, and its impact-investments manager joined Fortera's board as an observer — an anchor customer funding the plant that will serve it.
What has to be true
- Do not ask cement makers to rebuild: ReCarb bolts onto a working kiln, and the plant makes more saleable cement from the same limestone.
- An ASTM-approved product that matches ordinary cement performance removes the industry's stock excuse that green building materials underperform.
- Microsoft's procurement rights and attribute certificates turn a climate investment into committed demand that justifies a first full-scale plant.
What can be applied
Do not ask a commodity industry to replace its machines; sell the bolt-on that turns their waste into product, and fund the first big plant with an anchor buyer who needs the emissions cut.
Aftermath
As of September 23, 2025 Fortera ran the 15,000-ton Redding plant, had placed ReAct in real pours such as DPR and UC Berkeley, and counted lime producer Graymont among partners. Microsoft's Climate Innovation Fund invested to support a first full-scale 400,000-ton-per-year facility, securing procurement rights and environmental attribute certificates toward its 2030 carbon-negative goal; impact-investments manager Erik Urosa joined the board as an observer. Fortera's claim is cost parity with ordinary Portland cement plus roughly 70% lower CO2 — a retrofit, not a green premium.
Sources
- Fortera Lowers Carbon Emissions with Opening of its First Industrial Green Cement Plant
- New lower-carbon cement plant captures CO2 from normal cement plant
- Fortera Secures Microsoft Funding for Low-Carbon Cement Production
- Microsoft invests in Fortera to scale low-carbon cement production
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