At the StatoilHydro-operated Sleipner fields on the Norwegian continental shelf, carbon dioxide from produced gas is captured and stored in a subsea aquifer. Emissions of more than 10 million tonnes of carbon dioxide to the atmosphere have been avoided since production started in 1996. This is more carbon dioxide than the total number of cars in Norway emit in two years.
The Sleipner West reservoir, south on the Norwegian shelf, was discovered in 1974, and Sleipner East in 1981. The fields have been in production from 1996, including the world's first CCS plant for natural gas, which stores carbon dioxide at approximately 1,000 metres below the sea bed. The natural gas contains close to 9% carbon dioxide in its natural state, and since the market specification permits a maximum CO2 content of 2.5%, it is necessary to reduce the carbon content in the gas before it is exported.
The Norwegian CO2 cost of approximately USD 50 per tonne of CO2 including CO2 tax and climate quota costs, makes the capture and storage process cost-effective.
The Sleipner CCS plant was the first full-scale commercial CCS plant in the world, and it is still the largest single emission reduction measure in Norway. After 10 years of storage, seismic monitoring shows no signs of leakage from the subsea reservoir. When the EU finalises its directive on carbon storage, our experience of carbon storage may be beneficial to other European storage projects.