Norway’s petroleum industry has been working to cut emissions, even before climate change became hot on the agenda. Statoil has been pumping CO2 emissions back into the seabed underneath the Sleipner field for the past 13 years. Thirty percent of greenhouse gas emissions saved during the period 1994-2007 were in fact from carbon capture and storage (CCS) from Sleipner, according to the KonKraft 5 report produced on behalf of its members, the Norwegian Oil Industry Association, Federation of Norwegian Industries, Norwegian Shipowners’ Association, and Norwegian Confederation of Trade Unions.
The decision to store rather than flare was motivated in part by the Norwegian carbon tax introduced in 1991. The tax has been influential in helping reducing emissions per unit produced on the Norwegian Continental Shelf by 9% from 1990-2006. Norway’s petroleum sector emits an average of 8 kilograms of greenhouse gas emissions per barrel of oil equivalent, making it one of the most carbon-efficient in the world, according to KonKraft. So how was the Norwegian petroleum industry able to cut an annual average of 4.5 million tonnes in greenhouse gas emissions in 2006?
Energy Savings & Reduced Flaring
Norwegian greenhouse gas emissions from its continental shelf accounted for about one quarter of the country’s total 55 million tonnes emitted in 2007. Turbines on the offshore installations are the largest source of carbon dioxide (CO2) and nitrous oxide (NOx) emissions from oil and gas activities, while flaring accounts for about 10%.
Half of the reductions come from energy savings and reduced flaring. One of the biggest examples dates back to 1998, when ConocoPhillips upgraded turbines as part of the Ekofisk II development. This led to an annual carbon cut of slightly more than 1 million tonnes. ConocoPhillips took the decision to upgrade its turbines as part of its redevelopment of the Ekofisk field, the first Norwegian oil and gas development. It went from the old 1970s turbines and generators to modern BAT (best available technology) low NOx equipment supplied by General Electric.
Several factors have led to the drop in CO2 emissions, such as more fit for purpose (better match with gas compression needs – better to operate fewer gas turbines with high load than many with low load), Statpipe subsea by-pass (no compression of transported gas for third party) and shut down of four smaller fields resulting in reduced gas compression needs, according to Stig Kvendseth, a ConocoPhillips spokesman.
Other example are Exxon Mobil, which cut 100,000 tonnes per year at the Balder field by improving the compressor regularity and flaring procedures and Statoil, which cut 30,000 tonnes per year by improving compressor efficiency at Åsgard B.
The KonKraft report said the petroleum industry has further identified about 40 new measures that could reduce carbon emissions a further 800,000 tonnes by 2013 using cost-effective energy savings and less flaring.
Carbon Capture & Power from Shore
Other areas where the industry has achieved substantial reductions are carbon capture and storage (CCS) and powering offshore platforms from shore.
The petroleum sector cut 30% of greenhouse gas emission during 1994-2007 from CCS in the Sleipner area. Statoil has been capturing 1 million tonnesof CO2 from natural gas production on the Sleipner field in the North Sea and storing it in a aquifer more than 800 metres below the seabed since 1996.
CCS has also been initiated for natural gas production on Statoil’s Snøhvit field in the Barents Sea. This development marks the world’s first gas liquefaction plant with CCS. The company has
avoided more than 700,000 annual tonnes of carbon dioxide as of 2009.
The industry achieved the remaining 20% of the greenhouse gas cuts during the period 1994-2007 by supplying power from shore to Kollsnes, including the Troll A platform, and the start-up phase for Ormen Lange. In the future, Statoil’s Gjøa field will have partial power supply from shore for a floating installation and avoid 250,000 tonnes of CO2 from 2010. BP’s Valhall field will have full power supply from shore through rebuild and renewal. It should avoid 300,000 annual tonnes of CO2 from 2010.
KonKraft estimates the industry can potentially avoid a further 5.5 million tonnes in annual carbon emissions through a partial supply of electricity from shore to existing fields and through carbon capture at the planned Mongstad combined heat and power station, the Mongstad crackerand the gas-fired power station stations at both Kårstø and Mongstad. However, there are discussions regarding CCS at Kårstø due to high costs and low utilisation. This represents about 10% of Norway’s greenhouse gas emissions.
Statoil, together with Gassnova and Norske Shell, are building a carbon capture facility known as the European Carbon Technology Centre (TCM) at Mongstad, which should be ready by early 2012. Aibel, Aker Clean Carbon, and Alstom Norway have been awarded master contracts for the projects.
The industry will also be able to use its expertise in constructing and operating installations to help the development of offshore wind power. Fred Olsen Group, which provides offshore drilling and production services, made its first investments in renewable energy in 1997 in a wind power park in Scotland. Most recently, Statoil’s Hywind project, offshore Norway, became the world’s first full-scale floating wind turbine to come on-stream.