Subsurface sequestration of carbon dioxide - an overview from an Alberta (Canada) perspective

To stabilize the atmospheric concentration of greenhouse gases (GHG), a hug e reduction of carbon dioxide (CO2) emissions is required. Although some pe ople believe that this necessitates a considerable reduction in the use of fossil fuels or fuel switching, other options are available that allow the use of fossil fuels and reduce atmospheric emissions of CO2. Sequestration of CO2 from fossil fuel combustion in the subsurface could prevent the CO2 from reaching the surface for millions of years. Geological sequestration o f CO2 in deep aquifers or in depleted oil and gas reservoirs is a mature te chnology. Despite the huge quantities of CO2 that can be sequestered in thi s way, this approach does not provide any economic benefit. This paper disc usses a third option, which consists of injecting CO2 in deep coal seams to sequester the carbon and enhance the recovery of coalbed methane (CBM). Wa ste CO2 from CBM-fueled power plants could be injected into CBM reservoirs to produce more methane (CH4) for the power plant. The 2:1 coal-sorption se lectivity for CO2 over CH4 supports the feasibility of operating fossil-fue led power plants without atmospheric CO2 emissions. Other CO2 sequestration technologies, such as ocean disposal and biofixation, are briefly discusse d and the suitability of these approaches is evaluated for use in Alberta, Canada. (C) 2000 Elsevier Science B.V. All rights reserved.