Carbon capture and storage (CCS) is a process that captures carbon dioxide (CO₂) from industrial sources or directly from the air, transports it and then stores it in safe underground geological formations. Here is a more detailed explanation of how CCS works:
The first step in CCS is to capture carbon dioxide emissions. There are different technologies and methods for capturing CO₂, depending on the source. The most common method is post-combustion capture, where CO₂ is separated from the flue gas after the combustion of fossil fuels. Another technique is pre-combustion capture, used in industrial processes such as gasification, where CO₂ is captured before the fuel is burned. Captured CO₂ can also come from natural gas processing or direct air capture.
Once the CO₂ is captured, it must be transported to the storage site. Transport can be via pipelines, trucks, ships or even by converting the CO₂ into a solid form such as dry ice to make it easier to transport. The choice of transport method depends on the distance to the storage site and the volume of CO₂.
The final step is to store the captured CO₂ deep underground to prevent it from entering the atmosphere. This is usually done by injecting the CO₂ into suitable geological formations. The most common storage sites are depleted oil and gas reservoirs, deep seawater reservoirs and unminable coal seams. These formations must have certain characteristics to ensure safe and long-term storage of the CO₂, such as impermeable rock layers on top to prevent leaks and sufficient storage capacity for large volumes of CO₂.
It is also possible to utilise the captured CO₂ by reusing it for various purposes, such as the production of chemicals and food, as a fuel or for use in industrial processes. This allows the CO₂ to be put to good use rather than simply stored.
Monitoring and Verification:
Continuous monitoring of stored CO₂ is essential to ensure its integrity and to detect potential leaks. Various monitoring techniques are used, such as seismic monitoring, geochemical analysis and satellite monitoring. This helps to verify the effectiveness of the storage site and ensure the safe storage of CO₂.