4.2 Carbon capture technologies

The combustion of fossil fuels generates CO₂. Power stations that use fossil fuels are large-scale emitters of CO₂, and because they are large scale they provide an opportunity to capture and store the CO₂ rather than emitting it to the atmosphere. Small-scale emitters, like domestic gas boilers, do not provide the same opportunity, particularly for storage. Large-scale emitters make the necessary piping and infrastructure more cost effective and practicable.

Pre-combustion technology. This is where the carbon is captured from the hydrocarbon fuel before combustion, producing hydrogen, which in turn can then be used as a clean fuel.

The fuel, which might be methane or coal that has been gasified, is converted into hydrogen and carbon monoxide. The carbon monoxide is converted into CO₂ and then separated from the hydrogen ready for storage.

The BBC News article ‘BP pulls out of green power plant’ provides information on the cancellation of this project.

Post-combustion technology. As the term suggests, this involves capturing the CO₂ from the flue gases after combustion. More information, including the advantages and disadvantages of this type of capture, can be found at the Scottish Centre for Carbon Storage.

An example of a test scheme that has just started is provided by ScottishPower’s Longannet power station.