Oil and gas industry emissions and discharges 2010

16/06/2011 Emissions of CO2 and NOx from petroleum activities are relatively stable. Discharges to the sea of produced water and oil have not changed much in the last few years either.

The authorities and the oil industry agree that there are too many accidental discharges on the Norwegian shelf. The operators are working to reduce the number.

This is clear from the operating companies’ annual reports of emissions and discharges. These reports are submitted simultaneously to the Climate and Pollution Agency (Klif), the Norwegian Petroleum Directorate (NPD) and the Norwegian Oil Industry Association (OLF) in EnvironmentWeb – a shared database for the authorities in the oil and gas industry.


Carbon dioxide (CO2)
In 2010, emissions from petroleum activities amounted to 12.6 million tonnes CO2. This is a small increase from 12.4 million tonnes the previous year. 

According to Statistics Norway (SSB) and Klif, Norwegian emissions of greenhouse gases amounted to 53.7 million tonnes of CO2 equivalents in 2010, up 4.8 per cent from 2009. In 2010, the oil and gas industry was responsible for approx. a quarter of Norway’s greenhouse gas emissions, which is the same level as the previous year. Greenhouse gas emissions from oil and gas activities have been relatively stable over the past ten years.

Nitrogen oxide (NOx)
In 2010, total NOx emissions from petroleum activities were 50 048 tonnes. This is a small increase from 2009, when emissions were at 49 650 tonnes. Total emissions of NOx from petroleum activities have seen relatively little change over the past few years.

According to SSB and Klif, total Norwegian emissions of NOx amounted to 189 000 tonnes in 2010, an increase of approx. 4 per cent from 2009. The oil and gas industry was responsible for 26.5 per cent of national emissions, a drop from 29.7 per cent in 2009.

Volatile organic compounds (nmVOC)
In 2010, the petroleum industry’s emissions of nmVOC amounted to 36 990 tonnes. This is down 18 per cent from 2009, when emissions of nmVOC were at 45 503 tonnes. Since 2001, total emissions of nmVOC have been reduced by over 85 per cent. The significant reductions in emissions are a result of an order imposing reduced emissions and industry investments in facilities to prevent evaporation or to recycle oil vapour on storage ships and shuttle tankers.

According to SSB and Klif, total Norwegian emissions of nmVOC were 135 000 tonnes in 2010. The oil and gas industry was responsible for 27.4 per cent of national emissions. The measures implemented offshore are the main reason Norway now fulfils the Gothenburg protocol – the international environmental agreement against long-range air pollution – regarding nmVOC.

Production discharges to the sea

Produced water
Oil production usually involves production of some water. The amount of water from each field increases as the fields get older and the reservoirs are depleted. The water is either injected back into the reservoir or cleaned and discharged.

In 2010, 131 million cubic metres of produced water was discharged on the Norwegian shelf, down from 135 million cubic metres in 2009. This is for the most part due to reduced oil production on the Norwegian shelf.

The authorities require that the oil content in discharged water is as low as possible. It must not exceed 30mg dispersed oil per litre of water. The average concentration in 2010 was 11mg per litre. In total, 1443 tonnes of dispersed oil was discharged to sea in 2010, a reduction of approx. 3 per cent as compared with the previous year.

Significant environmental improvements have been achieved as a result of the goal of zero discharges of oil and environmentally harmful substances to the sea. According to Klif, the target for reduction of environmentally harmful substances from produced water has not been reached yet. Oil companies are continuing to work on the issue to reduce these discharges further.

Operators on the Norwegian shelf conduct regular environmental monitoring. This monitoring has so far not proven effects of significance as a result of discharges of produced water.

Discharge of chemicals
Chemicals are classified in accordance with Klif’s system as green, yellow, red or black. Chemicals in the green category will not damage or be harmful to the marine environment; chemicals in the yellow category are usually not defined as hazardous, while chemicals in the black and red categories are prioritised for substitution and strictly regulated. They are only to be discharged where there are important safety or technical reasons for doing so.

Discharges of added chemicals totalled 139 000 tonnes in 2010. Green chemicals accounted for 91.6 per cent, yellow approx. 8.4 per cent, while red and black represented 0.01 per cent and 0.002 per cent respectively. In total, approx. 53 000 tonnes of chemicals were injected.

After the goal of zero discharges of oil and hazardous substances to the sea was introduced in 1997, operating companies on the Norwegian shelf have worked purposefully to replace chemicals with negative environmental properties with more environmentally friendly alternatives. This has resulted in the phasing out of 99.6 per cent of red and black category chemicals. Report to the Storting No. 26 (2006-2007) states that the goal of zero discharges for added chemicals has been reached. Work will continue to replace the remaining hazardous chemicals.

Accidental discharges to the sea

2010 saw 140 accidental discharges of oil, compared with 147 the previous year. In 2010, seven of these discharges were greater than one cubic metre and 31 were greater than 50 litres. The total volume of oil from accidental discharges in 2010 was 111 cubic metres, down from 114 cubic metres in 2009.

The number of accidental discharges of oil on the Norwegian shelf increased slightly during 2004-2008, but has gone down again after this.

2010 saw 158 accidental discharges of chemicals, a slight fall from 162 in 2009. The number of accidental discharges of chemicals has been relatively stable over the last ten years.

The total volume of all accidental discharges on the Norwegian shelf was 6376 cubic metres. Like the three years before, this volume is higher than normal. The reason for this is leakage of cuttings and drilling fluid from injection.

Injection is a measure which has been used to reduce discharges from oil and gas production on the Norwegian shelf for several decades. It offers both significant environmental gains and is cost-effective compared with e.g. disposal on land. However, several leakages from injection have been discovered over the past few years. The authorities and the companies have together concluded that this is due to insufficient knowledge of leakage mechanisms in connection with injection, as well as insufficient evaluation of the injection zone in the reservoirs.

For this reason, a complete examination of all fields which use injection has been carried out. In addition, an advisory expert panel has been appointed, which ensures quality control of the status of the injection wells. In addition, the authorities will impose stricter requirements with regard to selection and follow-up of future injection locations.

The authorities and the oil industry agree that there are too many accidental discharges. The oil companies are working purposefully to reduce the number. 


OLF: Tore Killingland, director strategy and environment
Telephone: +47 51 84 65 93, mobile: +47 917 52 604, email: tk@olf.no 

NPD: Arne Holhjem, director environment and energy
Telephone: +47 51 87 60 00, email: arne.holhjem@npd.no

Klif: Hanne Marie Øren, section for the oil and gas industry
Telephone: +47 22 57 37 82, mobile: +47 920 26 650, email: hanne-marie.oren@klif.no               


Updated: 16/06/2011