The impact of carbon capture and storage on climate

Carbon capture and storage (CCS) is being widely discussed as a possible mitigation option for limiting the emissions of carbon dioxide (CO2) from fossil fuel burning power plants. The implementation of CCS requires the resolution of a number of difficult policy, engineering and economic issues. Here we address the efficacy of CCS from the perspective of climate science. Implementation of CCS makes power stations less efficient, in the sense that they produce more CO2 for a given output of electricity, a feature which is characterised by the so-called energy penalty. The captured CO2 is then stored in, for example, geological storage reservoirs, from which some small fraction is expected to leak back into the atmosphere each year.