Petroleum activities in the Norwegian Continental Shelf generated 13.5 million tonnes of carbon emissions in 2015.
That’s a 3% increase – or 400,000 tonnes – compared to 2014, according to the Norwegian Petroleum Directorate.
It stated the main cause of the increase was start-up difficulties on the Knarr field and the Valemon and Edvard Grieg fields, which started producing oil in 2015.
Total CO2 emissions from fields that were operational before 2015 were on the same level as in 2014, it added.
However, Nitrogen Oxide (NOx) emissions fell by 11% due to reduced drilling activity and use of mobile facilities.
These emissions are largely generated as a result of gas and diesel combustion in turbines, engines and boilers that keep the facilities operational.
Safety flaring of gas, ventilating and diffusion gas emissions from storage and loading of crude oil are also sources of CO2 emissions.
The Norwegian Petroleum Directorate expects CO2 emissions to stabilise around 2015 levels for the next five years.