Norwegian continental shelf can be final depository for CO2
Svein Tønseth
Norway and the nations of the EU have underground "storage" for between 100 and 300 years worth of CO2 emissions from their biggest sources of industrial pollution.
Oil reservoirs as final depositories for CO2 are among the scenarios being studied by IKU for the EU. Storing carcon dioxide in this way would also enable it to improve oil recovery rates. In the course of an earlier Norwegian study, IKU looked at the possibility of using this technology to deal with emissions from a potential Norwegian gas-fired power station.
This is shown by the preliminary results of a study sponsored by the EU´s Joule II research programme, in which IKU Petroleum Research, a member of the SINTEF Group, is a participant. The study shows that a large proportion of this storage capacity is under the seabed on the Norwegian continental shelf.
The evaluations of storage capacity were made during the startup phase of a major project in which IKU´s reservoir experts are collaborating with researchers from four other European countries. The European Commission has asked the project group to determine to what extent it would be technically and economically feasible to make large-scale underground depositions of CO2.
Pipelines and boreholes
In the scenario that IKU is helping to evaluate, CO2 will be separated from the flue gases produced by fossil-fuel power stations and process industry. The carbon dioxide will then be transported by pipeline to boreholes on land or offshore, where it will be pumped deep into the earth for storage in empty gas reservoirs, water-bearing geological strata or oil reservoirs. It will also be of interest to find out if CO2 can be used to enhance oil recovery, whether or not water injection has already been employed. In the EU project, IKU´s responsibilities include studies that will determine the extent to which CO2 storage can be combined with enhanced oil recovery.Two schools of thought
"Among international professionals, there are two schools of thought regarding depositing CO2: underground storage on land and undersea storage. In my opinion, both concepts might be an option, and therefore both should be investigated, says Erik Lindeberg, the senior scientist who is leading IKU´s part of the EU project.The project deals with one of several problems being studied by the EU in connection with the CO2 limit which has been adopted for Europe. The EU has ratified the Rio Convention, which requires concentrations of atmospheric CO2 to be stabilized at a level which will not result in anthropogenic climatic changes.
Senior scientist Erik Lindeberg.
Thirty times Norway´s total emissions
Together with their colleagues from overseas, the IKU scientists will identify which conditions must be satisfied to allow CO2 to be stored safely and economically underground. Several unknown factors will have to be clarified, for example the question of whether CO2 injection can result in elevation of the land above the depositories.The study deals with the EU nations and Norway. The scientists began by looking at the quantities of CO2 that could be made available for underground storage.
"If this is to be economically realistic, the most appropriate strategy will be to deal with emissions from major sources. Small sources will only be of interest when they lie close to large ones. On this basis, we regard it as being theoretically possible to deal with around a billion tons of CO2 a year; if you like, thirty times as much as Norway´s total emissions of CO2 And these are cautious estimates," says Lindeberg.
Plenty of storage under the North Sea
Norway alone has a large proportion of Western Europe´s total CO2 storage capacity. The EU projects introductory studies show that the structures beneath the North Sea would be capable of swallowing 10 - 15 times as much CO2 as the land areas of the countries covered by the report.Preliminary estimates of storage capacity show that oil and gas reservoirs alone have room for 10 - 15 years of emissions of the available CO2 "If we include water-bearing strata under land and the sea, we estimate that the underground storage capacity of Norway and the EU countries is big enough to swallow the same quantity of CO2 for 100 to 300 years," says Erik Lindeberg.