Turning Carbon Dioxide into Stone in Iceland
One of the companies supplying technology to the new US plants is the Swiss firm Climeworks, one of several companies, along with Carbfix and ON Power, based in Iceland, doing pioneering work in turning carbon dioxide into stone. Several US senators visited Iceland in July 2023 to gain firsthand insights into these groundbreaking initiatives. Iceland, famous for having the lowest carbon emissions in the world, relies almost exclusively on thermal energy. Nevertheless, it has pushed into the field of carbon sequestration with innovative technologies.
The idea is simple: CO2 is mixed with water and injected deep into bedrock, where it mineralizes and forms calcite and is stored in the bedrock forever. When first tried in 2006, it was daunting, going from work in the laboratory to face the actual conditions on the surface and below—especially brutal weather conditions, malfunctioning equipment, and frozen pipes. The breakthrough came in 2016 and was announced to the world through a scientific paper. The title of the journal article in Science was appropriately stilted in science-speak, but the message was clear “Inject, Baby, Inject!” Carbfix scientists and engineers, for the first time, had demonstrated that CO2 could be permanently disposed as environmentally benign carbonate minerals in basaltic rocks. The researchers demonstrated that basaltic rock reacts rapidly with captured carbon dioxide. They mixed gasses generated by the Hellisheidi geothermal power plant with water and injected the mixture into volcanic basalt. Over 95 percent of the CO2 injected in the CarbFix site was mineralized in less than two years, much faster than the hundreds or thousands of years previously thought for such geological actions.
In a more recent paper, CarbFix geologist Sandra Ó. Snæbjörnsdóttir and her colleagues argue that carbon capture and storage has a fundamental role in achieving the Paris Agreement goals of limiting human-caused warming to 1.5 degrees Celsius. Further, such efforts in Iceland need to be accelerated in other parts of the world to achieve these goals.
In May 2024, the biggest carbon capture plant in the world was opened in Hellisheidi. Dubbed “Mammoth,” the plant owned by Climeworks will remove 36,000 metric tons of carbon each year, the equivalent of removing 8,600 internal combustion automobiles.
Could the techniques and procedures found in Iceland be replicated in the United States? Major basalt formations in the United States are found in Georgia, Alabama, the panhandle of Florida, in Oregon, Washington, and Idaho. Indeed, a subsidiary of Occidental Petroleum plans to create a far bigger plant in Texas and estimates that it will remove 500,000 metric tons of carbon per year, roughly equivalent to the emissions generated by 119,000 internal combustion cars. Climeworks is designing an even larger plant, scheduled for Louisiana, that will capture 1 million tons of carbon, replacing the emission of 238,000 automobiles.
Sources: Juerg M. Matter, et al., “Rapid Carbon Mineralization for Permanent Disposal of Anthropogenic Carbon Dioxide Emissions,” Science 352 (6291) (June 10, 2016): 1312-1314, https://www.science.org/doi/abs/10.1126/science.aad8132. Sandra Ó. Snæbjörnsdóttir, et al., “Carbon Dioxide Storage Through Mineral Carbonation,” Nature Reviews Earth & Environment 1 (2020): 90-102, https://www.nature.com/articles/s43017-019-0011-8#citeas. Nicolás Rivero, “The World’s Largest Carbon-Capture Plant Just Switched On,” Washington Post, May 9, 2024, https://www.washingtonpost.com/climate-solutions/2024/05/09/climeworks-mammoth-carbon-capture/.
