The petroleum activities on the Norwegian continental shelf result in the lowest greenhouse gas emissions by far per barrel of oil produced anywhere in the world.
However, due to the high level of production of oil and gas, these emissions nonetheless account for a large proportion of Norwegian emissions.
Since 1991, Norway has imposed a high carbon dioxide tax on emissions on its continental shelf. This has resulted in measures being implemented on the platforms and at oil and gas terminals onshore that are unparalleled in other countries.
The authorities and the environmental organisations have seen the electrification of the continental shelf from the land-based national grid as an important measure for further reducing carbon dioxide emissions. It is a prerequisite that the electricity production used to supply the platforms has a significantly lower carbon dioxide content per kilowatt hour than the facilities' own gas turbines.
As the first major offshore facility in the world, we have for several years operated the big Troll gas field using electricity from the onshore power grid. The most important reason for this is to reduce emissions of greenhouse gases and nitrogen oxides.
The Gjøa oil and gas field will be run in a corresponding manner using power from the Mongstad Energy Plant once the plant is put into operation in 2010. As a result of electrification from Mongstad, Gjøa will be operated with very low carbon dioxide emissions. If Gjøa had not been electrified, the emissions would have been considerably higher, corresponding to the emissions from 100,000 cars every year.
The electrification of platforms has been examined in several rounds of studies conducted over many years. Every time, it has been shown that electrifying existing platforms from onshore will prove very costly, often several times as much as the carbon tax.
Considerable amounts of energy can be saved by using new technology to separate water and sand from the well stream. The world's first full-scale seabed facility for the separation of water and sand from the well stream has now started up on the Tordis field. This technology represents a breakthrough for a new generation of subsea solutions in the oil industry and it saves energy.
Separated water and sand are pumped down into the Utsira formation directly from the subsea facility and stored there. This solution means that large volumes of water that accompany the well stream from the reservoir no longer have to travel the 10 kilometres to Gullfaks C and up to the surface. This saves energy.
The subsea development on Tordis is part of a project that is aimed at increasing the recovery rate from the Tordis field from 49 to 55 per cent. That is equivalent to roughly 35 million barrels of oil in addition to associated gas. Tordis, which is located in block 34/7 on Tampen, started production in 1994. The technology is particularly well-suited to developments at great ocean depths or far from land, and in areas where nature and weather conditions mean that subsea development is the best solution.
