Norwegian Shelf: NOx Emission to Remain Stable in the Years to Come

The total nitrogen oxide (NOx) emissions on the Norwegian shelf have remained relatively stable since the turn of the century. The prognoses indicate that they will remain at the same level in the years to come.

This is according to the Norwegian Petroleum Directorate’s new status report for NOx emissions, policy instruments and emission-reducing technology in the Norwegian petroleum industry as of 2012.

The petroleum sector is responsible for just under 30 per cent of the Norwegian NOx emissions. Operation of turbines is still the largest source of emissions. New technology has been developed which results in considerably lower emissions compared with the old turbines, and all gas-powered turbines that have been put to use after the new millennium are therefore low-NOx types. Low-NOx turbines that can run on both diesel and gas (dual fuel) have been utilised on the shelf with good results in the past four-five years.

On operating fields, replacement of old turbine technology with low-NOx is costly and complex, and has therefore not been widely implemented. The replacement has taken place naturally as fields are shut down and entire platforms are replaced. For example, old turbines have been replaced with low-NOx technology on Ekofisk, and Valhall now receives its power supply via a subsea cable from shore. Power from land reduces both CO2 and NOx emissions because this prevents a need to burn gas in turbines to generate power. Energy efficiency measures and a reduced power need on certain platforms means that a few turbines are no longer in operation.

An NOx tax was introduced in 2007. An NOx fund was established the following year where shipping companies, oil companies and individual fields on the shelf can join. Participation in the fund grants an exemption from the NOx tax, which is replaced with a lower fund tax. Under the fund scheme, the taxes directly fund emission-reducing measures. The majority of the measures are on ships. However, oil and gas facilities have also received resources from the fund, for example the water injection pilot on Troll C.

Measures in the oil and gas sector represent 10 per cent of the emission reductions triggered by measures supported by the NOx fund, an increase from 7 per cent in 2009. In comparison, the investment cost of these measures constitutes 36 per cent of total investment costs from all sectors. The figures show that measures in the petroleum sector are still expensive compared with other sectors, but that the percentage of measures in the petroleum sector is increasing.