Environmental sustainability of electricity generation systems with carbon dioxide capture and storage : working paper

The aim of CCS is to reduce the emissions from industrial point sources of CO2, which principally result from the combustion of fossil fuels. Figure 1 is a diagram of a coal-based CCS power generation system with storage in an offshore setting. The life cycle starts with the mining of the coal, which is transported to the power station. CO2 generated in the coal combustion process, which would otherwise be emitted to the atmosphere, is captured at the power plant, compressed and sent to a geological storage site which, in the UK, is most likely to be offshore. Transport to the storage site will probably be by pipeline, although part of the transport route could be by ship. Once at the storage site, the CO2 will be injected into a deep underground storage reservoir such as a depleted oil or gas field, or a suitable structure in a saline water-bearing reservoir rock (saline aquifer) via a well or wells. The goal of storage is permanent containment of the CO2. However, the possibility that at some point in the future a portion of the stored CO2 could leak to domains where it could cause adverse environmental effects also needs to be considered in a full life cycle analysis.