Greenhouse gas emissions
along the Norwegian gas value chain in 2016
Introduction The purpose of this report is to shed some light on the emissions related to natural gas produced on the Norwegian Continental Shelf and delivered to Statoil’s main gas markets, the UK and Germany. It provides an overview of methane and total greenhouse gas (GHG) emissions associated with offshore production, gas processing, subsea pipeline transportation to Europe, and final distribution to customers. All estimates for the upstream and midstream emissions are based upon periodically reported data provided to the Norwegian authorities. As Statoil is not a downstream operator, estimates related to the downstream sector, including storage, transmission and distribution of gas, are based on the most recent European study, published by NGVA (Natural & bio Gas Vehicle Association) in May 2017 . The NGVA study represents both a continuation of, and a complement to, two other large studies: the Exergia study  and the DBI study , which were concluded in 2015 and 2016, respectively.
Can methane emissions offset the climate benefits of natural gas? Carbon dioxide is by far the most significant source of anthropogenic greenhouse gas emitted to the atmosphere, methane coming in second position (Figure 1 to the left). About 20% of all humaninduced methane emissions come from oil and gas production and distribution (Figure 1 to the right).
Figure 1: Global contribution of anthropogenic methane and other greenhouse gas emissions  and sources of anthropogenic methane emission 
Through combustion, natural gas generates about half as much CO2 as coal for the same quantity of energy generated. However, methane leakages along the value chain can reduce the natural gas climate benefit. Using the immediate warming effect and a GWP for methane of 100, a 3.2% methane loss rate will offset the climate benefit of combusting natural gas vs coal . However, this is a very conservative estimate: Statoil and the Norwegian authorities refer to the official GWP factors 16 defined in the 2007 4th Assessment Report Immediate 14 warming effect (AR4) of the Intergovernmental Panel on Climate GWP=100 12 Change (IPCC) and apply a methane GWP of 25. 10 The climate benefits of natural gas compared to coal can then be demonstrated for methane loss 8 rates up to 14% . 6
Long-term warming effect GWP=25
Figure 2: Influence of different Global Warming Potentials (GWP) on the calculation of the methane loss rates for which the climate benefits of natural gas compared to coal disappear.
Maximum methane loss rate for a net climate benefit of natural gas compared with coal
Maximum methane loss %
Greenhouse gases from the oil and gas industry consist of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The global warming potential (GWP) of these gases is dependent on the timeframe taken into consideration.
Norwegian gas production and distribution to the European market Total gas production (i.e. total exported volumes from producing assets) in Norway was 116 million Sm³oe in 2016 (Figure 3). Of the 116 million Sm³oe of gas, Statoil-operated units on the Norwegian Continental Shelf (NCS) produced 80 million Sm3oe  , representing approximately 69 % of all gas production on the NCS in 2016.
Total per day
Gas (40 MJ)
Figure 3: Historical and expected production in Norway, 1970-2021 (source: Norwegian Petroleum Directorate ) Rich gas from Statoil-operated NCS installations is piped to two onshore gas processing facilities, Kårstø and Kollnes, where the rich gas is separated into liquid products (i.e. propane, butane, naphtha and stabilised condensate) and natural gas. Gas from the Shell-operated Ormen Lange field gas i processed in Nyhamna. The liquid products are shipped to customers worldwide, while the natural gas is compressed and transported by subsea pipelines to the UK and central Europe (Figure 5). The pipelines utilised for subsea gas transport are constructed from sections of steel pipe welded together and coated to decrease friction and resulting pressure fluctuations. The pipelines are also designed to tolerate high pressures, typically between 157 and 212 bar. As there are very limited number of connections and flanges in the subsea pipeline system, the risk of methane leakage is very low.
Millon barrels o.e. per day
Million Sm3 oe
Of the total gas production, liquefied natural gas (LNG) was close to 7 million Sm³oe in 2016. Hammerfest LNG is the only large-scale LNG production facility in Europe. The LNG produced at the Hammerfest LNG facility is transported by vessels to Europe and the rest of the world. All other natural gas produced on the NCS is transported to Europe by pipelines.
Figure 4: Gas pipelines on the NCS 
Figure 5: First destination of the gas produced on the NCS by country in 2015 (source: Norwegian Petroleum Directorate )
Two thirds of the gas produced enters the EU through either the UK or Germany. The remaining gas produced is exported primarily to France and Belgium. The German entrance points are through Europipe I/II and Norpipe to Emden and Dornum. In the UK, the Easington and St Fergus gas terminals are connected to the Langeled and Vesterled pipelines as well as to the FLAGS (Far north Liquids and Associated Gas System) transport system in the British sector of the North Sea. About 40% of the gas consumed in Europe is used by residential and commercial customers. In addition, power and heat generation accounts for 28% of the gas consumption while the industry uses about 22% of it as feedstock. The remaining 10% are used for a range of other applications.
Emissions related to the gas value chain Calculation of upstream and midstream emissions Natural gas is primarily produced together with oil and condensate. The energy generated on the installations is used for the total production of oil, condensate and gas. Hence, the specific allocation of relevant emissions to the gas value chain is not straightforward. The same issue exists for emissions related to onshore gas processing, where the natural gas gets separated from the liquid products. To adress this methodological challenge, a standard and pragmatic approach consists into allocating GHG emissions on the basis of the the energy content of the different hydrocarbon streams produced. The GHG intensity for the natural gas value chain is then calculated by dividing the allocated GHG emissions by the quantity of natural gas produced, excluding the gas re-injected for production support purposes. The emission and production data used in this report are the GHG emissions reported to the Norwegian authorities for 2016 . The methane emissions are quantified using the updated methodology developed by the industry and the Norwegian authorities, published in June 2016 .
Estimation of downstream emissions The downstream sector of the value chain is characterized by its complexity, the distribution of the natural gas streams across countries and borders depending on the commercial conditions in the European market. As Statoil is not directly involved in the downstream sector, neither as operator nor partner, the company does not have access to a primary set of emissions data for the downstream sector. Hence, data from the most recent overview study, published by NGVA (Natural & bio Gas Vehicle Association) in May 2017 and executed by the consulting company thinkstep , have been used. This study is a continuation of, and a complement to, two other large studies carried out respectively by Exergia for the European commission DG Energy in 2015  and by DBI in 2016 . While NGVA uses an approach and methodologies closely related to the ones used by DBI and Exergia, the NGVA study builds upon a larger proportion of primary data collected directly among the operators, including Statoil. The NGVA study addresses lifecycle emissions for the transportation sector. In order to enable a comparison between Statoil’s results and the NVGA figures, the emissions specifically related to the transportation sector (e.g. fuel dispensing) have been subtracted from the NGVA data.
Results and discussion Total GHG emissions Figure 6 and table 1 presents the natural gas value chain GHG intensity from the Statoil study compared with the NGVA study. 1. The Statoil study includes: Natural gas produced at the Norwegian Continental Shelf, processed at onshore facilities in Norway, transported by subsea pipelines and distributed to customers in the UK and Germany. 2. The NGVA study includes: Natural gas produced and processed in the EU, Russia, Norway and other gas producing countries, transported by pipelines or as LNG, and distributed to customers in Europe. The average GHG intensity is shown for different parts of Europe, where the UK is included in EU North and Germany is included in EU Central.
GHG intensity - from production to delivery to customer [g CO2eq/GJ]
Statoil Germany Statoil UK EU South West* EU South East* EU Central* EU North* EU total* 0
UPSTREAM + MIDSTREAM: gas production, processing and transport DOWNSTREAM: gas transmission, storage and distribution
Figure 6: Greenhouse gas intensity in the gas value chain (* = results from NGVA study, May 2017)
Germany GHG INTENSITY (gCO2eq/GJ)
EU Central (NGVA)
United Kingdom STATOIL 1487
EU North (NGVA)
Processing Transport Terminals UPSTREAM + MIDSTREAM
Transmission Storage Distribution
Table 1: GHG intensity along the gas value chain for the gas distributed in EU Central and EU North (NGVA study) and for the Norwegian gas distributed in the UK and in Germany (Statoil study) * data from NGVA EU central; **data from NGVA EU North The comparison between the estimates obtained for the Norwegian gas in Statoil’s study and the results from the NGVA study indicates that the GHG intensity for the gas produced in Norway is low compared to gas production in other countries. This can be explained by a high focus on energy optimization and extensive emission reduction programs driven by safety risk and a high carbon tax. The use of renewable hydropower electricity at the Norwegian onshore gas processing plants also contributes to the total low value chain GHG emissions. Besides, NGVA estimates result from the use of a model based on standard emission factors (thinkstep GaBi 5), while the Statoil’s study is directly based on the emission data reported to the Norwegian authorities for 2016 . The NGVA results for the different EU regions also cover all natural gas delivered to each region, including LNG, which contributes to higher emissions figures.
Methane emissions Figure 7 and Table 2 present the methane emission ratios in both the Statoil and the NGVA studies. The NGVA study does not show methane emission data for the different EU regions nor per producing country; NGVA just reports the average methane emissions for all gas consumed in Europe. Gas consumed in Europe originates from production in EU and imports. Norway is the second largest gas supplier to Europe, after Russia, and followed by Algeria, Qatar, Nigeria and Libya .
UPSTREAM + MIDSTREAM DOWNSTREAM TOTAL 0.0
% methane leakage
STATOIL Average Europe, NGVA
Figure 7: Methane emission ratio (%) along the gas value chain from production to delivery to customers for Norwegian gas to UK/Germany (Statoil) and average gas to Europe (NGVA) % METHANE EMISSION
Average for all gas consumed in EU (NGVA)
Norwegian gas to UK/Germany (STATOIL) 0.012
Processing Transport Terminals UPSTREAM +MIDSTREAM
Transmission Storage Distribution
Table 2: Methane emission ratio along the natural gas value chain (* = data from NGVA EU Total)
Figure 8 visualises the contribution of methane emissions to the total GHG emissions for the up- and midstream part of the value chain for Norwegian gas. This contribution is small, less than 4% of the total emissions. Figure 8: CO2, methane and non-methane volatile organic compound (NMVOC) contribution (%) to the total GHG emissions in the Norwegian gas upstream and midstream sector (Statoil study)
One of the main outcome from this study is that the methane emissions in the upstream and midstream sectors are considerable lower for Norwegian gas than for other gas streams to Europe. This can be explained by several factors, in particular a high focus on limiting methane emissions at offshore installations due to safety risk and the extremely low gas leakage rate for subsea pipelines already mentioned from Norway to the UK and Germany. According to the NGVA study, the upstream and midstream sectors appear as the major contributors to methane emissions in Europe. However, the situation is different for the gas produced and processed in Norway. For Statoil’s gas value chain, from production in Norway to delivery to customers in the UK and Germany, the upstream and midstream sectors represent less than 10% of the total methane emissions. Overall, methane contributes to less than 4% of the total GHG emissions in the upstream and midstream Norwegian gas sector, while the NGVA study shows that over 27% of the GHG emitted along the European gas value chain are due to methane. Finally, the level of total methane emission levels along the gas value chain largely confirms a significant climate benefit of natural gas compared to coal. This is the case both for Norwegian gas delivered to customers in the UK and Germany, with emission rates below 0.3%, but also for all gas consumed in Europe, with an average emission rate of 0.6%.
Conclusions The GHG intensity associated with the Norwegian gas delivered to customers in the UK and Germany appears to be significantly lower than the corresponding average for all gas consumed in Europe. CO2 is the main greenhouse gas associated with the upstream and midstream sectors of the Norwegian gas value chain. Methane represents just 4% of the total GHG emissions. For the gas value chain from the Norwegian Continental Shelf to end-users in the UK and Germany, the results of our study indicate that over 90 % of the methane emissions occurs in the downstream part of the gas value chain, i.e. in the transmission and distribution segments. Considering the gas value chain from production to delivery to customers in the UK and Germany, the methane emissions associated with Norwegian gas are below 0.3%, while the average for all gas consumed in Europe reaches 0.6 %. The estimated levels of methane emissions secure the climate benefits of natural gas compared to coal, both for the Norwegian gas and for the average of all gas consumed in Europe.
NGVA – Greenhouse Gas Intensity of Natural Gas
EXERGIA: Study on actual GHG data for diesel. Petrol. Kerosene and natural gas. July 2015
DBI: Critical Evaluation of Default Values for the GHG emissions of the Natural Gas Supply Chain. October 2016 (executive summary- DBI to be contacted for complete report)
IGU Amsterdam Executive Committee meeting. Fugitive Methane Emissions. 10.19.2016 (IGU members restricted) (executive summary- DBI to be contacted for complete report)
U.S. EPA’s Global Anthropogenic Emissions of Non-CO2 Greenhouse Gases: 1990–2020 (EPA Report 430-R-06-003)
IPPC 4th Assessment Report AR4. Chapter 2
Alvarez R. A., Pacala S.W., Winebrake J., Chameides W.L. and Hamburg S.P. 2012, PNAS. vol. 109. no.17. pp. 6435–6440
Statoil Annual report 2016
Norwegian Petroleum Directorate
10. Gassco website 11. Norwegian Environmental Agency. report M-515 12. NOROG Environmental report for 2016 13. Eurostat 2016
COS - 170135. July 2017
Statoil ASA NO-4035 Stavanger Norway Telephone +47 51 99 00 00 www.statoil.com