Sequestration of waste carbon

• The combustion of fossil fuels and the transfer of carbon from geological store to the atmosphere and oceans is the main driver of present-day global warming
• One possible solution to this problem is to capture and store CO2 released by power plants and industry. This new technology of carbon sequestration is known as carbon capture and storage (CCS)
• So far the technology has been piloted at just a handful of coal-fired power stations. It involves three stages. First the CO2 is separated from power station emissions. The CO2 is then compressed and transported by pipeline to storage areas. And finally it is injected into porous rocks deep underground where it is stored permanently
• In the USA 40% of all CO2 emissions are from coal- and gas-fired power stations and CCS has the potential to reduce these emissions by 80-90%
• CCS's effectiveness is limited by economic and geological factors. This is because CCS:

  • involves big capital costs - the Drax and Peterhead projects will cost at least £1 billion
  • uses large amounts of energy - typically 20% of a power plant's output is needed to separate the CO2 and compress it
  • requires storage reservoirs with specific geological conditions, i.e. porous rocks overlain by impermeable strata