Climate impact of potential shale gas production in the EU

Gas can be extracted from ‘Gas shales’, rocks that are formed by deposits of mud, silt, clay and organic matter. These porous rocks can have natural gas trapped within them, and in order to extract it, the rocks must be fissured, or fractured. These new gas resources are getting more and more interesting for exploitation as conventional resources are getting less abundant. The European Commission is looking at the safety and climate implications of the extraction of these new resources in Europe.

The present report from AEA Technology analyses and discusses these estimates for each step of electricity production from shale gas, taking into account the direct and indirect emissions associated with gas extraction, transportation and use, including pre-production and production phases (excluding the exploration stage).

What is the climate impact to be expected from shale gases production in the EU?

Some studies, which have received a lot of media attention, have concluded that the lifecycle greenhouse gases (GHG) emissions from shale gas may be larger than conventional natural gas, oil, or coal when used to generate heat and viewed over the time scale of 20 years. However the majority of studies suggest that globally, emissions from shale gas, although slightly higher than conventional gas, would produce significantly less (by 41% to 49%) greenhouse gases emissions than coal.

Overall, it is estimated that the potential greenhouse gas emissions that might be associated with shale gas exploitation in the EU are about 60-70 g CO₂ per MJ of thermal energy, or 472gCO₂eq per kWh of electricity generated which is slightly higher (by 4-8%) than with conventional gas resources. It is also estimated, although with less certainty, that the greenhouse gases emissions from shale gas exploitation in Europe is overall slightly lower than those coming from importing conventional gas from sources outside of Europe.

Like for conventional gas resources, the combustion of shale gases is the main source of CO₂ emissions. . However, emissions also arise from their pre-production, production, processing and transmission stages even if overall, the importance of the emissions at these stages is lower. The second greatest contributor to emissions is the completion and installation of the extraction well. The fracturing process can lead to methane emissions when the fluid used is brought back to the surface, and such emissions are not present in conventional gas extraction.

There are still uncertainties regarding GHG emissions in the production step. Also, the management of waste (waste water in particular) generated by shale gas extraction will also influence their global GHG emissions.

Are there other impacts to be expected from shale gas exploitation in Europe?

Due to the generally higher population densities in Europe, it is argued in the report by some that shale gas developments might have a smaller overall land-footprint compared to the current exploitation of shale gas underway in the United States, or to conventional gas production in Europe as developers may be under more pressure to reduce the impact of well developments on the landscape, although this would require further analysis. There are however uncertainties about the level of re-use and treatment of the wastewater generated by the extraction process.

The regulatory framework of the EU will need to be adapted in order to take into account shale gas exploitation. Regarding in particular the reporting of these emissions, the current EU reporting framework, made with the UNFCCC and the IPCC, does not include any data specific to shale gas extraction. The way the reporting is done in North America could be used as a basis to adapt the EU reporting to the reality of shale gas extraction.

For more information on shale gas you can also see our highlight on the potential health and environmental risks related to the exploitation of shale gas in Europe : https://www.greenfacts.org/en/shale-gas/