The emission into the atmosphere of sulphur and nitrogen compounds causes acid rain, which can move across great distances, harm fresh water fish populations and damage forests and other vegetation.
Statoil’s on and offshore facilities use some gas and oil for operation. This generates NOx emissions. The majority of Statoil's products are used as fuel and for energy production, which also produces NOx emissions.
The volume of NOx that is formed primarily depends on the combustion temperature. NOx emissions can therefore be reduced using combustion technologies that use a lower temperature, or through the cleaning of exhaust gasses.
Sulphur dioxides (SO2) are formed when the fuel contains sulphur, and SO2 emissions can therefore be reduced by reducing the sulphur content of our products.
Natural gas contains very little sulphur, and oil from the North Sea also contains relatively little sulphur, but our refineries must reduce the sulphur content before our products can be sold.
Sulphur has a negative effect on cleaning systems which reduce emissions of NOx and other car exhaust pollutants.
This has resulted in increasingly strict requirements for the sulphur content in petrol and diesel.
Statoil has installed plants for the removal of sulphur from fuel at our refineries at Mongstad (Norway) and Kulundborg (Denmark) well before the EU’s requirement for reduced sulphur content was introduced. Mongstad and Kalundborg remove some 17 000 tonnes of sulphur annually that would otherwise have been emitted during the burning of the products. Furthermore Statoil's refinery in Kalundborg has established facilities for fertilizer production (ammonium thiosulphate) in order to reduce the emissions.
We have started using low-NOx turbines, and today, one out of every five turbines is of this type. At our onshore facilities, turbines and burners are continuously being upgraded to low-NOx technology. The use of low-NOx turbines on platforms reduces emissions by some 85 per cent, which represnts some 300 tonnes of NOx a year per turbine. Overall the our offshore low-NOx turbines reduce emissions by several thousand tonnes per year.
We are also assessing other methods of reducing NOx emissions. In particular this applies to areas where it would be difficult or extremely expensive to use “conventional” low-NOx technology.
Statoil has started using supply vessels that run on natural gas rather than diesel.
Such third-party measures can be environmentally and economically beneficial alternatives to implementing measures at our own facilities.