COSTS OF CO2 DISPOSAL OPTIONS

The cost of CO2 disposal may represent a large part of the cost of any ''Low CO2 Power Generation'' system. Disposal options, considered in this paper, are to pipe the CO2 as a liquid to disused oil/gas fields or to the deep ocean or to pipe an aqueous solution of CO2 to the ocea n. British Coal have employed an engineering contractor, Bechtel Ltd, to estimate the cost of pipelines to dispose of the CO2 produced from a conceptual 500 MWe power station in the UK East Midlands. Three opti ons were considered:-a pipeline to a North Sea gas field a pipeline to the nearest enclosed ocean basin with a depth greater than 4000 m and a sill height of greater than 400 m a pipeline to beyond the continen tal shelf Designs were developed taking into account pipeline route, s afety, maintenance, geology and topography. Installation of the overla nd pipes is conventional. For the continental shelf section, lay-barge technology is established for the size of pipes specified. The deep s ea section presents new frontiers in lay-barge technology and capacity but it is believed that, with upgrading of equipment, the capability to lay such a pipe could probably be developed. Costs were developed f or the overland, continental shelf, and deep sea sections of pipeline. The results of this exercise show that pipeline costs range from 1/2- 3/4 million pounds per kilometre. For the option involving disposal of an aqueous solution of CO2 the pipeline cost dominates, so this conce pt is only applicable to locations where the continental shelf is narr ow. This study is part of British Coal's programme of work on Low CO2 Power Generation. Other aspects of the programme include the calculati on of the marginal cost of CO2 removal at the power plant site. The co st of CO2 transport is added to the cost of removal to give the overal l cost of CO2 abatement. These costs range from 20-120 pounds per tonn e of CO2 emission avoided, depending on the type of power plant and th e CO2 separation and disposal options chosen.