Carbon capture and storage (CCS), also known as carbon capture, utilisation, and storage (CCUS), is a process that involves capturing carbon dioxide (CO2) emissions from industrial processes and power plants, transporting it to a suitable storage location, and securely storing it underground or using it for other purposes.
The process typically consists of three main steps:
Capture: Carbon dioxide is captured from large-scale industrial sources, such as power plants or cement factories, before it is released into the atmosphere. Various technologies are employed for capturing CO2, including post-combustion capture (removing CO2 from flue gases), pre-combustion capture (separating CO2 before the combustion process), and oxy-fuel combustion (burning fossil fuels in pure oxygen to produce a concentrated CO2 stream).
Transportation: Once the CO2 is captured, it needs to be transported to a suitable storage site. Typically, pipelines are used to transport the CO2 over long distances, similar to natural gas pipelines. Alternatively, it can be transported by ships or trucks in the form of compressed or liquefied CO2.
Storage: The captured CO2 is stored underground in geological formations such as depleted oil and gas fields, saline aquifers, or deep coal seams. These formations provide secure and permanent storage for the CO2, preventing its release into the atmosphere. The CO2 is injected into the storage formations and stored deep underground, where it can be trapped and eventually mineralise over time.
Carbon capture and storage is considered an important technology in efforts to mitigate climate change. By capturing and storing CO2 emissions, it helps reduce greenhouse gas concentrations in the atmosphere, thereby mitigating global warming. It can also be used in certain industrial processes to reduce emissions directly at the source. Additionally, the captured CO2 can be utilised in enhanced oil recovery (EOR) projects, where it is injected into oil fields to enhance oil extraction and store the CO2 simultaneously.
However, it's worth noting that while carbon capture and storage has the potential to play a role in reducing CO2 emissions, it is not a standalone solution to climate change. It should be seen as a part of a broader strategy that includes transitioning to renewable energy sources, improving energy efficiency, and adopting sustainable practices in various sectors of the economy.