NOx emissions from the offshore installations in Norway have until now not been subject to regulations. As one of the main contributor of nitrogen oxides (NOx) emissions, regulations have been foreseen. Several studies have been initiated on behalf of The Norwegian Oil Industry Association (OLF) since 1990 to acquire knowledge about the industry's NOx emissions.

A common set of emission factors and a detailed inventory for NOx have been established. NOx reduction measures have been studied and installation of Dry Low Emissions (DLE) combustion technology for gas fueled turbines on new installations appears to be the most realistic NOx reduction measure in the near future. A cost efficiency curve for implementation of this technology has been established. Contribution to the environmental impact from the Norwegian oil and gas industry as regards acidification, fertilization and ground level ozone concentrations have been calculated based on first results obtained by a newly developed dispersion modeling tool.

An open dialogue with relevant regulatory bodies was promoted throughout the studies. As a result, a common approach for NOx reductions has been found and results achieved have been utilized by the authorities in their work to establish a national action plan for NOx.


Norway has ratified the 1988 Sofia Protocol on NOx to the Convention on Long-Range Transboundary Air Pollution which entered into force 14.02.1991. The Protocol called for a stabilization of emissions by 1994 compared to the 1987 level. Norway also signed a declaration of intent to reduce the NOx emissions further by 30% within 1998 based on the 1986 level. Projection of the national emissions shows that the objective for 1998 will not be met unless new measures are implemented. As the oil and gas industry contributes with 14% of the emissions on a national level in 1992, there is a need for reductions. Fig. 1 show the major contributors of NOx emissions in Norway and Fig. 2 the prognosis for the oil and gas industry until the year 2000.

Regulation of NOx emissions has been foreseen. The introduction of a NOx tax is not considered to be an economically nor an efficient alternative to reduce NOx emissions. More cost efficient reductions can be achieved by other means where the industry and authorities join their forces. This has been the basic approach for work with environmental matters for the Norwegian offshore oil and gas industry.

As the authorities were working towards a national action plan for reductions of NOx, the industry needed to know more about its emissions, the possibilities for reduction and inherent cost in order to assess the potential future consequences for the industry. As this was an area of mutual interest within the different companies, work was conducted as a joint effort through OLF.

Cooperation between OLF and the authorities was initiated in order to achieve a common understanding of the situation and to avoid double work.

The purpose of this paper is to describe the approach to improve knowledge of the NOx emissions and to present results from three recently completed studies;

  1. Emission factors and inventory for the Norwegian Continental Shelf (NCS),

  2. evaluation of technologies for NOx reductions, including scenarios for implementation of Dry Low Emissions (DLE) combustion technology on gas fueled turbines with related cost efficiency calculations and

  3. environmental impact from the Norwegian oil and gas industry and contributions to acidification, fertilization and ground level ozone concentrations.

A White Paper concerning Norwegian policy for handling NOx emissions was issued in June 1995. This opens up for negotiated agreements with the industry as a regulatory measure to facilitate reductions for e.g. NOx. In order to be prepared for possible negotiations on emission reductions, new studies were initiated in 1996. The scope is to establish cost efficiency figures for other NOx reduction technologies, including associated marine activities as well as further development of the dispersion modeling tool.

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