Manufacturers Trap CO2 in Concrete

Carbon dioxide has been removed from the air and “permanently stored” in concrete for the first time, according to E&E News’ ENERGYWIRE (subscription).

What’s going on: Central Concrete, a subsidiary of manufacturer Vulcan Materials Co., along with Heirloom Carbon and CarbonCure Technologies, announced late last week they had successfully sequestered approximately 80 pounds of carbon dioxide as calcium carbonate.

• The gas was captured from the air with a process using limestone, then injected into recycled water collected from washing out concrete trucks.
• “The CO2 reacted with the cement in the water and mineralized, and the resulting CO2-treated slurry was used in new concrete mixes at a Central Concrete plant in San Jose, Calif., according to a joint press release from the companies. They say the CO2 will remain trapped in the concrete for centuries.”

Permitting problems: Looking to concrete—the world’s second most-used material—to store carbon dioxide make sense because of its ubiquity. Currently, there is a lack of infrastructure needed to transport and store the gas underground, while the well-permitting process is extremely lengthy. 

• “Carbon capture and removal advocates say permitting [Class VI] wells, [used to inject carbon dioxide into rock for long-term storage,] takes too long under EPA, which directly issues the permits in all states and territories except for North Dakota and Wyoming.”
• “EPA acknowledged in an October report that the process could be streamlined and told lawmakers it is updating the application and review process to improve efficiency.”