This is proposed as a means of extracting carbon dioxide and then storing it, typically underground, in order to reduce emissions of the greenhouse gas to the atmosphere. The main application initially is likely to be in the energy industry in enabling the generation of electricity more cleanly from fossil fuels (coal, oil, natural gas). In addition, CO2 capture and sequestration is linked to the Hydrogen Economy in that in the short to medium term, the means of generating hydrogen in bulk are likely to involve reformation of fossil fuels, particularly natural gas and there will be pressure to minimise the CO2 output from these processes.
A report on the technology and economics of CO2 capture and sequestration has been commissioned from Sheffield University and this is due to be issued in the near future. Other industries, which are major emitters of CO2 have been identified including, in particular, the cement manufacturers who may need to invest in capture and disposal of the gas. The CO2 capture element of the process will involve very significant investment in large-scale plant, which will extract the gas from waste streams using one of a number of possible technologies (e.g. “amine scrubbing”) and then compressing it for pipeline transmission.
The process of sequestration will entail the transport of bulk quantities of CO2, probably via pipelines, to suitable storage sites, most of which are expected to be underground in appropriate geological features, which it is hoped will trap and retain the gas for very long periods of time. The most suitable sites identified to date are located undersea and examples are already in use or planned in the North Sea (e.g. the Norwegian Sleipner field has been in operation for several years). An initial Horizon Scanning paper on the likely implications for HSE of a process involving the transport of large quantities of the gas for injection underground via existing or new oil/gas wells has been generated already by OSD.
In addition to issues around necessary changes to legislation to reflect the possible change of use of existing wells and pipelines, a range of technical concerns have been identified. These include e.g. concerns over the metallurgical conditions, the handling of other by-products from the extraction process (such as methane and H2S), the compression stage and venting procedures, all of which could impact on the health and safety of operators.