Technical Description

Carbon capture and storage (CCS) is an innovative technology designed to capture, transport and securely store CO2 underground, preventing its release into the atmosphere.  

In fossil-fired power plants, the CO2 content in the flue gas varies between 3 and 15 % of total flue gas volume, depending on the type of fuel and power plant process. CO2 capture and storage (CCS) is best suited for large point sources of CO2 such as power plants. The process involves three main steps:

1. Capture of CO2.
2. Transportation to an injection sink.
3. Underground geological injection.

Several CO2 capture systems are already available on a smaller scale, but generally, they can be divided into three groups:

• Post-combustion capture: CO2 is separated from flue gas using absorption in chemical solvents. The captured CO2 is removed from solvents through temperature increase, dried, compressed, and sent for storage. 
• Pre-combustion capture: CO2 is removed before the actual combustion process in connection to coal gasification or decarbonisation of natural gas, which produces hydrogen and CO2. The hydrogen is then used as fuel. The removed CO2 is compressed and transported to the storage.
• Oxy-fuel combustion: Before combustion, nitrogen is removed in the Oxy-fuel method. Fuel is burned in an oxygen-rich environment along with recycled CO2. Flue gas will contain only water vapour and CO2. Water vapour can be condensed to yield a concentrated CO2 stream, which can be purified, compressed, and transported for storage.

The primary obstacle to the widespread adoption of CO2 removal technology is the expensive process of separating and compressing CO2. The additional energy needed for this task usually decreases efficiency by roughly 10%.[1]

Carbon capture and storage [1]