From Direct Air Capture to Concrete: How Heirloom and CarbonCure are Kicking off a New Era for Carbon Mineralization

History was made Wednesday, February 1st. CarbonCure and Heirloom launched their partnership in building carbon-removing concrete. CO2 removed from the air by Heirloom’s Brisbane, CA power plant was connected to CarbonCure operational units at Central Concrete’s San Jose facilities, both for ready-mix and for reclaimed water from concrete operations.

For the past several years, many engineered solutions for capturing and sequestering carbon have been developed in parallel as scientists, engineers, and others work to find new avenues to address the climate crisis. Direct air capture technology, which pulls CO2 from the air and oceans for years (e.g. Heirloom), and carbon-removing building materials through mineralization (e.g. CarbonCure) are two such examples. What’s new and novel is that we are now finding ways to combine these technologies to further advance climate goals.

For many years, the carbon dioxide removal community has hoped that this particular commercial combination would form—direct air capture plus CO2-to-concrete. Unfortunately, cost, risk, and scale of business have gotten in the way of a viable integration. But finally, the gift of geographic co-location paved the way: CarbonCure has commercial operations in San Jose, California, while Heirloom is in Brisbane, just a 25 minute drive away. Proximity unlocked the potential.

Last week, I had the honor of celebrating the culmination of this partnership at an event hosted at Central Concrete’s San Jose offices. I was joined by many business leaders, scientific experts, and financiers in the CarbonTech and CO2 removal community to witness the joint commercial launch and physical hook up of CO2 canisters.

After initial welcomes, we took a small bus to the main loading facility where the concrete waste-water reclamation and the bulk of the dry and wet concrete loading takes place. Mixing trucks were washed out (3-7% residual by volume) to produce chemically reactive waste-water suitable for carbon mineralization. The Heirloom team brought eight CO2 canisters (the first of which the whole company signed) and CarbonCure hooked up the canisters to their equipment. At that moment, history was made.

The first CO2 tank, signed by the Heirloom team.

The Carbon Capture to Concrete Process

Once the CO2 is bound in mineral form within the concrete, it is stored indefinitely—for decades, or most likely centuries. If that CO2 is pulled from the air, the concrete produced removes CO2 and binds it through mineralization, resulting in permanent CO2 removal and enabling the generation of new supplies of valid, durable CO2 removal credits for the voluntary carbon market.

To be clear, these are small volumes—at best a few tons of CO2. By comparison, a large cement plant emits 5-10 million tons of CO2 each year! Also, the life cycle of cement and concrete is not zeroed out through this process. However, the combined reductions and removals of CO2 from the two processes are substantial—up to 30% of the total in concrete production. It also creates a tantalizing possibility: If the upstream emissions of cement and concrete can be reduced through other means (e.g., alternative fuels, new processes, CO2 capture and storage), then the CarbonCure-Heirloom process would create climate-restorative building materials—new CO2 minerals that bind CO2 pulled from the air.

The process would also benefit from new government policies for low-carbon building materials like New Jersey’s new 2023 low-carbon concrete bill, LECCLA. Recognizing that concrete production accounts for more than 7% of global atmospheric carbon emissions, LECCLA provides tax credits for low carbon cement and concrete purchases within the state Similar laws are under consideration in New York and California, with potential federal adoption as well. In addition, expanded tax credits in the Inflation Reduction Act of 2022 provide additional incentives for operations like Heirloom and CarbonCure—up to $135/ton CO2 capture and used—which will dramatically increase the profitability of the present venture and incentivize new projects and expansions.

This kind of technical innovation, matched by innovation in policy and business models, makes the future look bright. Someday soon, we can build cities and modern infrastructure out of atmospheric carbon dioxide. That would be better than just limiting the harm of those emissions—carbon-negative infrastructure could be part of a climate counterstrike to remove and hold millions of tonnes for hundreds of years, deliberately and durably reversing greenhouse gas emissions.