Over 90% of the CO2 produced by fossil fuels at large fixed installations can be captured and prevented from reaching the atmosphere. There are three main technology types for CO2 capture - pre-combustion, post-combustion and oxy-firing - allowing CO2 to be captured from industrial processes such as power generation, oil refining and cement manufacture.
Pre-combustion capture involves partial combustion of CO2 to produce hydrogen and CO2. Hydrogen combustion produces no CO2 emissions, with water vapor being the main by-product. The component parts of pre-combustion technology exist today at commercial scale; the challenge now is to integrate these in a power application.
In post-combustion capture, the CO2 is removed after combustion of the fossil fuel. CO2 is captured from exhaust gases and other large point sources. Post-combustion can be installed on both new and existing power plants – of vital importance given that the average power plant operates for 40 years. The challenge around post-combustion is scale-up of the technology to commercial scale in a power application, as well as integration.
Oxy-firing involves burning fuel in pure oxygen instead of air. This results in an exhaust gas (made up largely of CO2 and water) which is ready to be dried and compressed for storage.
Oil refinery - one of the industries for which capture technologies are being developed. Image courtesy of Suncor.