A new study indicates that an extinct offshore volcano in Portugal could potentially store 1.2-8.6 gigatons of carbon dioxide, representing 24-125 years of the country’s industrial emissions. The method termed ‘in situ mineral carbonation’ allows CO2 to react with specific rock types to create new, safely stored minerals.
Rocks that contain large amounts of calcium, iron and magnesium are great candidates for this process-such as the volcanic basalts that make up most of the sea floor. With this in mind, the researchers targeted an offshore volcano for a few reasons-the structure of the volcano could provide an ideal architecture for carbon injection and storage, the rocks are the right type for the reaction involved, and the location is not too close to large populations, but also not too far.
Most carbon capture projects have relied on injection of carbon dioxide into porous sedimentary basins that are sealed to prevent release of the gas out of the reservoirs. In these cases, the carbon will eventually start to form minerals, but over longer periods of time-decades to centuries.
In 2016 researchers reported that 95% of carbon dioxide injected into underground basalts in Iceland had mineralized within just two years. The much shorter time scale makes the process safer and more effective – once carbon is stored in minerals, problems like potential leaks are not a concern.
Davide Gamboa, co-author of the study, said, “What makes mineral carbonation really interesting is the time. The faster it gets into a mineral, the safer it becomes, and once it’s a mineral, it is permanent.”
www.scitechdaily.com/extinct-offshore-volcano-could-store-up-to-8-6-gigatons-of-carbon-dioxide