CarbonCure Technologies, Central Concrete and Heirloom Achieve First-Ever Concrete Storage of Atmospheric CO₂ Captured By Direct Air Capture

Direct air capture combined with permanent storage of CO₂ will be crucial to achieving climate goals

Feb 3, 2023 - Carbon dioxide (CO₂) captured via direct air capture (DAC) has been permanently stored in concrete for the first time, in a demonstration project led by CarbonCure Technologies and Heirloom

Heirloom captured CO₂ from the atmosphere using their DAC technology at their headquarters in Brisbane, California. CarbonCure’s reclaimed water technology injected the captured CO₂ into the process wastewater at a Central Concrete batch plant in San Jose, California. Central Concrete used the CO₂-treated wastewater to make fresh concrete, which was produced for a range of construction projects across the Bay Area. The CO₂ is durably sequestered in the concrete as calcium carbonate, and will not be returned to the atmosphere, even if the concrete is demolished. 

Heirloom runs America’s only operational DAC facility. It uses limestone, an abundant, easy-to-source and inexpensive material, to pull CO₂ from the air. Harnessing a cyclic process, the limestone is broken down into calcium oxide rock and CO₂ gas using heat from a renewable-energy powered, electric kiln. The calcium oxide is spread onto vertically stacked trays where it acts like a sponge - pulling CO₂ from the air before it is returned to the kiln and the process begins again. The captured CO₂ gas is then permanently stored safely underground or – as was the case 1 February – embedded in concrete.

The global leader in permanent carbon storage in concrete, CarbonCure Technologies licenses a suite of carbon mineralization solutions for hundreds of concrete plants globally. CarbonCure’s reclaimed water technology was used to store Heirloom’s CO₂ at Central Concrete. The technology injects CO₂ into reclaimed water (recycled water collected from washing out concrete trucks) at concrete plants. When injected, the CO₂ immediately reacts with cement in the water and mineralizes, permanently storing the CO₂ and stabilizing the cement for reuse. The CO₂-treated slurry is then used in new concrete mixes.

Central Concrete’s role in this milestone DAC-to-Concrete demonstration project reflects their continued position as a concrete industry leader in designing, testing and delivering higher-performing concrete while significantly reducing the carbon footprint of construction projects. Central Concrete was the first concrete supplier in the Bay Area to adopt CarbonCure’s technologies for ready-mixed concrete, and continually offers innovative solutions for building and infrastructure projects. Their technical team focuses on cutting-edge research, quality assurance and sustainability considerations to provide solutions that match material performance requirements, environmental standards and constructability needs for the built environment.   

“This demonstration project is a global milestone for carbon removal technology that confirms concrete’s enormous potential as a climate solution that can permanently store carbon in our most essential infrastructure - from roads and runways to hospitals and housing,” said Robert Niven, Chair and CEO of CarbonCure Technologies. “We’re thrilled to be collaborating with Heirloom and Central Concrete on this groundbreaking world first.”

“The science is clear: In order to reach climate goals we must remove billions of tons of already emitted CO₂ from the atmosphere each year,” said Shashank Samala, CEO of Heirloom. “This is an important step toward that future and shows the promise of DAC technologies combined with smart, permanent methods of sequestration.”

This application of a DAC-to-concrete solution is a significant step forward in permanent atmospheric CO₂ removal. As the world moves toward zero-carbon energy generation, DAC technologies will play a key role in remediating past emissions, and helping to decarbonize industries as they develop and scale carbon-cutting solutions.

Even the most aggressive emissions reduction projections from the UN Intergovernmental Panel on Climate Change will require the removal of 6-10 billion tons of CO₂ per year by 2050 to stick to a 1.5˚C warming pathway. DAC technologies are some of the most promising methods of carbon dioxide removal, and have recently received large investments from the U.S. government through the Department of Energy’s $3.5 billion DAC hub program and the Inflation Reduction Act. 

The world’s most-utilized building material, concrete provides an important repository for permanent CO₂ storage. With the global building stock expected to double by 2060 - the equivalent of building another New York City every month - concrete presents a key opportunity to store immense quantities of carbon dioxide in our built environment.

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About CarbonCure Technologies

CarbonCure Technologies, a fast-growing carbon dioxide removal tech company, is on a mission to reduce and remove 500 million metric tons of carbon emissions annually—equal to taking 100 million cars off the road each year. CarbonCure’s suite of technologies permanently store captured CO₂ in concrete through carbon mineralization. With hundreds of systems operating across the global concrete industry and a methodology verified by Verra, CarbonCure’s technologies currently save from the atmosphere thousands of metric tons of CO₂ each month—with significant growth and impact, year-over-year. CarbonCure’s cutting-edge research and innovation have garnered global recognition and prestigious titles, most notably Carbon XPRIZE Grand Prize Winner, 2022 CNBC Disruptor 50 List Company and Cleantech 100 Hall of Fame Company. CarbonCure’s investors include Breakthrough Energy Ventures, Amazon, Microsoft, BDC, Carbon Direct, and Mitsubishi Corporation.

About Central Concrete

Central Concrete Supply Company, a Subsidiary of Vulcan Materials Company, has been serving northern California for more than 70 years with 20 plants across our San Francisco Bay and Sacramento area footprint.  Central Concrete’s focus on innovating sustainable, high-performing concrete mixes has made them the industry leader in sustainable solutions for the built environment. Central Concrete’s parent company, Vulcan Materials Company is the nation’s largest producer of construction aggregates—primarily crushed stone, sand and gravel—and a major producer of aggregates-based construction materials including asphalt and ready-mixed concrete. Our coast-to-coast footprint and strategic distribution network align with and serve the nation’s growth centers. 

About Heirloom 

Heirloom builds low-cost direct air capture technology that permanently removes CO₂ from the atmosphere, with a real path towards removing 1b tons of CO₂ by 2035. Our technology rapidly accelerates the natural ability of minerals to absorb CO₂ from the air from a timespan of years to days. Funded by Bill Gates’ Breakthrough Energy Ventures, Ahren Innovation Capital, Carbon Direct, Prelude Capital, Lowercarbon Capital and others, Heirloom’s customers are the world’s biggest buyers of carbon removal including Microsoft, Stripe, Shopify, Klarna and more.

Media contacts

Haley McKey, CarbonCure Technologies: media@carboncure.com 
Janet Kavinoky, Vulcan Materials Company: kavinokyj@vmcmail.com 
Alexa Dennett, Heirloom Carbon: alexa@heirloomcarbon.com

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