Managing methane emissions
An important part of the effort to tackle climate change is to cut methane emissions. Shell is using specialist equipment to find methane emission sources quickly and cost effectively.
The Intergovernmental Panel on Climate Change (IPCC) has estimated that around 370 million tonnes of methane are released into the atmosphere each year from man-made sources which, on a carbon dioxide (CO2) equivalent basis, makes up about 20% of total global greenhouse gas (GHG) emissions.
Methane is more potent than CO2; it has 34 times the global warming potential of CO2 over a 100-year time frame, according to the IPCC AR5 report. Reductions in methane emissions today will help to slow the rate of global temperature rise, as methane remains in the atmosphere for a much shorter time than CO2.
The regulation of methane emissions varies among countries. Shell and the industry are working with governments to highlight the challenges and help find the most cost-effective and efficient solutions for methane management. Any solutions should be informed by robust data and peer-reviewed science.
Methane in oil and gas production
Methane emissions associated with oil and natural gas production tend to occur in four main areas: combustion (emissions of unburnt methane from fuel combustion); flaring (where the flaring itself fails to burn all the methane); venting (including from equipment); and unintended emissions (for example, small leaks sometimes called fugitive emissions).
Reports by the Environmental Defense Fund (EDF)and the International Energy Agency have shown that gas used in power generation will continue to have lower total GHG emissions than coal, as long as methane leakage throughout the natural gas supply chain is less than 3% or 8% respectively. (The variation is due to assumptions made about how long methane emissions endure in the atmosphere.) The Environmental Protection Agency (EPA) in the USA estimates that total methane emissions in the natural gas supply chain – as a percentage of the global total volume of natural gas produced – are around 1.3%. This takes into account methane leaks during gas processing and transmission through pipelines for power generation.
Collaborating to reduce emissions
Shell has collaborated on academic studies to better understand methane life-cycle emissions. In 2014, we participated in a University of Texas and EDF assessment of methane emissions from tight-gas production in the USA. Recommendations from the study have been used as input for our programme to improve or replace equipment to reduce our methane emissions.
Shell has been a partner with the EPA Natural Gas STAR programme since 1995. The programme encourages oil and gas companies to adopt cost-effective technologies and practices that improve operational efficiency to reduce methane emissions. It also encourages the introduction of internal voluntary measures such as Shell’s onshore operating principles. (See Tight gas and oil).
In 2015, methane emissions contributed less than 5% of Shell’s GHG emissions on a CO2 equivalent basis. We recognise that it is important to reduce methane emissions from our operations. Methane from flaring and venting in our Upstream operations represented more than 45% of our reported methane in 2015. (For our flare reduction work, see Flaring).
There are also concerns that tight-gas production could cause fugitive emissions. Our reported methane emissions from the production of tight gas in 2015 were less than 0.5% of the gas produced from these assets. We have leak detection and repair programmes across our sites to identify unintended emissions or equipment that has high emissions so they can be replaced or repaired. Following successful pilots in the USA, Shell is now deploying advanced leak detection and repair technology using infrared cameras to scan for methane emissions.
Shell continues to work to identify all potential methane sources to help reduce our emissions. We report our methane emissions from these sources according to regulations and industry standards. We also monitor work in the industry for more accurate reporting methods.