Incidence sur le climat de la production potentielle de gaz de schiste dans l’UE

What are the objectives of this report?

The objective of this study is to provide state-of-the-art information to the European Commission on the potential climate implications (via greenhouse gas (GHG) emissions) of possible future technically recoverable shale gas (gas reserves trapped within shale rock ^[1]) resources in Europe to produce electricity. According to the report, these resources are of a similar scale to those technically recoverable in the U.S.

Certain process steps involved in the extraction of shale gas reserves are indeed more specific to unconventional gas extraction and the scale and complexity of operations differ from conventional practices. In particular, the extraction of shale gas typically involves a process known as hydraulic fracturing (fracking) where water, chemicals and proppants are pumped at high pressure into the well in order to open fractures in the rock and release the shale gas.

Drawing upon existing studies based on a narrow set of primary data from shale gas operations in the U.S, and their underlying data sources, a hypothetical analysis has been carried out of the potential lifecycle GHG emissions that may arise from shale gas exploitation within Europe.

The study provides also an assessment of the adequacy of GHG emissions reporting frameworks to cover fugitive emissions of the production of shale gas and, if needed, propose measures for its improvement.

The reports estimates also, through the use of appropriate models, each step of the lifecycle GHG emissions of electricity production from shale gas, taking into account the direct and indirect GHG gas emissions associated with gas extraction, transportation and use, including pre-production and production phases. However, emissions from exploration made to identify the potential exploitation wells of shale gases have not been taken into account, neither in any previous studies.

Finally the report provides an examination of the current EU GHG emissions reporting framework and explores the extent to which emissions from shale gas operations would be captured within the existing reporting requirements. Where there are identified gaps the report addresses the need for further reporting guidelines.

Drawing upon existing research this report provides an examination of the potential climate impacts of shale gas production in the EU, it begins with a review of existing estimates of GHG emissions from shale gas production and of the potential options for abating emissions from shale gas processes.

As highlighted by the authors, the results provided can be used as inputs to discussions around the potential role of shale gas in the future energy supply mix, or any potential implications of the exploitation of indigenous shale gas resources on the development of renewable or other energy sources in Europe.

What are the hypothetical greenhouse gases (GHG) emissions to be expected from E.U. shale gas production

Across a range of scenarios, the emissions from the use of shale gas to produce electricity are estimated to be in the range of about 60-70 g CO₂eq per MJ of thermal energy or 409 to 472 gCO₂eq per kWh of electricity generated. (see graph in the report p 64).

The majority of studies suggest that emissions from shale gas are lower than coal, but higher than conventional gas, based on other assumptions. Like for conventional gas, the emissions from shale gas are dominated by their combustion in the use phase even if emissions also arise from the pre-production, production, processing and transmission stages. But, overall, the importance of the emissions at these stages is less.

It is clear, according to the report that the greatest next contribution to emissions comes indeed from the extraction well completion stage, whether this is assumed to happen only once at the beginning of the production cycle, or several times as the well is worked over. The second most significant contribution of emissions in this stage are the drilling and the hydraulic fracturing. The emissions arise from a range of energy using sources including: powering drilling equipment; transport of water to site and waste water away from site; processes to supply water and treat waste water, and ‘embedded carbon’ in the proppant and chemicals used in the hydraulic fracturing fluid.

The other main factors affecting the estimates of GHG emissions from shale gas exploitation over its entire life cycle are:

• The overall lifetime shale gas production of the well;
• The methane emissions during well completion which are dependent on the quantity of methane in the flow back liquid and on the treatment of this methane (e.g. venting, flaring or green completion);
• The number of re-fracturing events and the associated increase in productivity that result from these.

2. How do GHG emissions with shale gas compare with those with conventional gas or coal?.

a) The comparison with conventional gas
The authors have estimated the GHG emissions per unit of electricity generated from shale gas to be around 4% to 8% higher than for electricity generated by conventional pipeline gas from within Europe. However, a number of uncertainties remain including:
1.) the level of emissions associated with the well completion stage ;
2.) the levels of water re-use and treatment of waste water.

These additional GHG emissions that do not arise from conventional extraction arise predominantly in the well completion phase when the fracturing fluid is brought back to the surface together with methane gas releases. If emissions from well completion were mitigated and used , through flaring or capture, , then this difference is reduced to 1% to 5%.

The analysis also suggests (but this conclusion is far from clear-cut) that the emissions from shale gas generation (base case) sources of gas outside of Europe which make a significant contribution to European gas supply would be 2% to 10% lower than emissions from electricity generated from sources of conventional pipeline gas located outside of Europe (in Russia and Algeria), and 7% to 10% lower than that of electricity generated from liquid natural gas (LNG) imported into Europe.

Under the ‘worst’ case shale gas scenario used in the study, emissions from electricity generated from shale gas would be similar to the upper emissions level for electricity generated from imported LNG and for gas imported from Russia and this suggests that in such cases there may be no GHG emission benefits from utilising domestic shale gas resources over imports of conventional gas from outside the EU1. In fact, for some pipeline sources emissions from shale gas may exceed emissions from importing conventional gas.

b) The comparison of emissions with coal. This relative comparison, although still largely hypothetical, is clearer cut. Based on experiences drawn largely from the U.S, emissions from shale gas generation would be significantly lower (41% to 49%) than emissions from electricity generated from coal, a finding consistent with most other studies into the GHG emissions arising from shale gas.

Would adoption of best available technologies significantly reduce GHG emissions from shale gas production?

The use of best practice techniques, one of the key assumptions which can influence the scale of emissions, has the potential to significantly reduce emissions relative to other practices. With respect in particular to emissions resulting from flow back from well completions, the application of Reduced Emissions Completions has the potential to reduce emissions by around 90%.

It seemed reasonable to the authors of this report to assume that a large proportion of the best practice techniques identified and that a regulatory requirement in the U.S. from 2015 would be applicable in Europe with some caveats related to:

• Geology : certain techniques requires sufficient gas pressure, which may not be the case at all locations in Europe;-
• Infrastructure: when the captured gas doesn’t meet the required natural gas specification and if the adequate processing infrastructure is not in place;
• Availability and experience in equipment / technology: further emissions reductions can be achieved at other stages in the gas life cycle. These measures are not specific to shale gas and are also applicable to conventional gas sources. These include measures such as: more efficient compressors; improved leak detection or utilisation of gas stemming from production testing.

How would their waste management influence the global GHG emissions from shale gas extraction?

Of the water used for hydraulic fracturing, a proportion (between 9 and 70%, depending on the studies) flows back. Of the water that flows back, some can be recycled, and used for hydraulic fracturing of other wells on the site. Re-use involves either straight dilution of the flow back water with fresh water or the introduction on-site of more sophisticated treatment options. These can range from using polymers and flocculants to precipitate out and remove metals to filtration technologies. These treatments would also impact the GHG emissions from Trend goes towards maximising reuse, although this can be constrained by high levels of contaminants in the flow back water, or a lack of other wells close enough for the water to be reused. The conservative assumption adopted in this report considers that anyway up to 50% of the water used for hydraulic fracturing ends up as waste water which must be treated. Flow back water can be disposed of in several ways, by tankering the water off site to dispose of by deep well injection, disposal in municipal sewage treatment works, or in a specialised industrial waste water treatment plant.

Alternative practice adopted in the U.S. is to store the waste water in open pits but such water would still require treatment before it could be disposed of. Some contaminants which are likely to be present in flow back water may not be properly treated in a standard municipal sewage treatment facility and can affect the plant This option is therefore not considered to be a viable option for disposal of flow back water as compared to more advanced treatment e.g. involving reverse osmosis (RO) but GHG emissions would also be associated with waste water transport and the electricity consumption of the RO process. Injection to deep well for disposal of waste water was not considered.

Is the present E.U. legislation adapted to the control of GHG emissions from shale gas production?

The study underlined that there are very few requirements in the existing E.U. legislation applicable specifically to GHG emissions from shale gas projects:

- The EIA Directive (85/337/EEC; 2011/92/EU (codified)) is the most relevant as it sets requirements as to the consideration of climate change effects and air emissions as part of a full EIA. However, despite the requirements of this Directive, many uncertainties remain as to whether Member States would require an EIA for shale gas operations and, if so, how Member States should implement the EIA such as the methodology to be used to quantify GHG emission baseline scenarios.

-The EU ETS Directive (Directive 2003/87/EC) could provide precedents for the regulation of shale gas emissions, through its treatment of venting and flaring, and emissions related to carbon capture and storage processes.

- The Directive on Industrial Emissions (2010/75/EU) exists but is not clear in which circumstances it would apply to shale gas exploration and exploitation activities and whether its measures on air emissions would cover methane contained within flow back.

What are the report’s main recommendations

The first recommendation of the report , is that development of evidence based, reporting systems, estimation methodologies and emission factors should focus on the most significant and most uncertain new sources of GHG emissions from shale gas exploration and production (E&P) sources, which are the fugitive methane emissions from well completions and well work-overs, including the management of hydraulic fracturing flow back fluids.

The report suggests thus regulatory constraints to be investigated that would encourage the application of best available techniques, among which ^[2]:

1. Consideration of the issues identified related to the scope of the EIA Directive with regard to shale gas exploration and exploitation activities (Annex I or II);
2. Consideration of information requirements on measures taken by developers to limit GHG emissions under the EIA Directive, or other pieces of relevant legislation;
3. Consideration of the need for measures to limit GHG emissions for shale gas exploration and exploitation;
4. Consideration of the issues identified related to the scope of the Industrial Emissions Directive with regard to shale gas exploration and exploitation activities;
5. Consideration of the application of the emission limit values requirements under the Industrial Emissions Directive to methane emissions from exploration and exploitation activities.
6. Consideration given to the application of emission limit values for methane emissions from exploration and exploitation activities.

In principle, the legislation described above could provide a good approach with which to enforce best shale gas technologies, although this would likely need to be supplemented by BAT reference documents, guidance specific to shale gas technologies and clarification on the applicability of key directives.

Alternatives, such as voluntary agreements, could also be considered, but additional measures would be required to ensure they are rigorously applied.

Are there specific requests specific to shale gas production in the current E.U. GHG emissions reporting framework ?

According to the report, no emission factors, neither GHG estimation methods or industry activity and emissions data specific to shale gas Exploration and Production (E&P) sources are included within the EU current GHG emissions reporting frameworks made under the auspices of the UNFCC and IPPC.

However, information and reporting protocols from regulators in Canada and the U.S.provide estimation methods and indicative emission factors for these sources that are specific to shale gas E&P which could be developed for application in the EU.

Several process stages in shale gas E&P, including processing and compressing the gas for distribution, require the same steps as with conventional gas. Therefore the current IPCC Guidelines and national GHG inventory methodologies should be adaptable to allow inventory agencies to derive complete and accurate estimates for these sources.

Reference: Climate impact of potential shale gas production in the EU Final Report Report for European Commission DG CLIMA AEA/R/ED57412 Date 30/07/2012 Issue 2  http://ec.europa.eu/clima/policies/eccp/docs/120815_final_report_en.pdf The report has been commissioned by DG Climate Action of the European Commission and delivered by AEA , in collaboration with CE Delft and Milieu. Contact Jonathan Perks, AEA Technology plc, Gemini Building, Harwell, Didcot, OX11 0QR e-mail:jonathan.m.perks@aeat.co.uk

^[1] ‘Gas shales’ (also known as shale beds) are formations of organic-rich shale, a sedimentary rock formed from deposits of mud, silt, clay, and organic matter. The low permeability of the rock means that substantial quantities of natural gas can be trapped within their pores, but the shales must be artificially stimulated (fractured) to enable its extraction. Techniques such as directional / horizontal drilling and hydraulic fracturing have been developed in order to facilitate the extraction of the gas from the shales.
^[2] see table 27 of the report, pg 104