Further information on technology maturity.
Technologies required for carbon capture include those for both separating and capturing CO2. Various separating techniques are available, and are suitable for different capture techniques. The main capture techniques are post-combustion capture, where CO2 is separated and captured from flue gas following combustion; pre-combustion capture, where a primary fuel is converted to CO2 and H2 and the two separated before the H2 is combusted; and oxy-fuel combustion where carbonaceous fuels are burned in pure O2 to produce flue gas which is pure CO2 and H2O, which are easily separated. Of these, the first two are considered technically ready for deployment.
Once CO2 has been captured it must be transported to the storage site. While there are various possible methods of transport, most focus has been on transport as a dense phase liquid along pipelines. Uncertainties exist with this technology. For example, it is unclear how impurities of different kinds would interact with the CO2 to affect overall fluid properties. In addition, in the case of pipeline fracture it is unclear what the fracture potential of the pipelines would be due to uncertainty regarding depressurisation characteristics; it is also unclear exactly how the CO2 would behave upon release.