CO2 capture is done at Sleipner with a conventional amine process. It was a challenge to design this process compact enough so that it could be placed on an offshore platform in the middle of the North Sea, 250 kilometres from land.
The extra equipment cost for the CO2 compression and the drilling of the CO2 injection well was roughly 100 million USD.
Until now eight million tonnes of CO2 have been stored. The spreading of the CO2 underground has been mapped in various research projects, which were partly financed by the European Union (EU).
In 1990 the Statoil operated gas/condensate field Sleipner Vest in the North Sea was in its planning phase. The natural gas at Sleipner contains naturally around 9% CO2. This was too much with respect to the customer requirements. The CO2 needed to be removed first.
In 1990 the Statoil operated gas/condensate field Sleipner Vest in the North Sea was in its planning phase. The natural gas at Sleipner contains naturally around 9% CO2. This was too much with respect to the customer requirements.
The CO2 needed to be removed first.In 1990 the Statoil operated gas/condensate field Sleipner Vest in the North Sea was in its planning phase.
The natural gas at Sleipner contains naturally around 9% CO2. This was too much with respect to the customer requirements. The CO2 needed to be removed first.
In 1991 the Norwegian authorities introduced a CO2 offshore tax with the aim of reducing CO2 emissions. At the moment this tax is around 50 USD/tonne. Motivated by this tax, Statoil proposed to remove the CO2 offshore and inject it into a deep geological layer below the Sleipner platform.
In this geological layer the CO2 will be stored for a long time, probably thousands of years. This layer contains porous sand rock filled with salt water, and is called the Utsira formation.
The CO2 is prevented from seeping into the atmosphere by a 800 metre thick gastight cap rock above this layer. The Sleipner license partners supported this idea. Its implementation meant a reduction in CO2 emissions of nearly one million tonnes per year, which was roughly 3% of the Norwegian CO2 emissions in 1990.
The field became operative in October 1996. This meant that the world’s first offshore CO2 capture plant was running, together with the world’s first CO2 storage project in a geological layer 1000 metres below the sea floor.
