Whilst some of the analysis remains relatively unchanged from the original document, other areas having undergone important revision, not least because industry estimates of shale gas reserves at the UK and global scales have markedly increased. For example in the UK industry reserve estimates published for a single licensing area are an order of magnitude greater than national estimates published by DECC in December 2010. New papers detailing fugitive emissions have also emerged raising concerns that shale gas production may involve greater greenhouse gas emissions than previously thought.
The analysis within this new report addresses two specific issues associated with the extraction and combustion of shale gas. Firstly, it explores the environmental risks and climate change implications arising from shale gas extraction. Secondly, it outlines potential UK and global greenhouse gas (GHG) emissions arising from an updated range of scenarios built using the latest predictions of shale gas resources.
Since our earlier analysis, a range of reports and journal articles on shale gas have been published, giving the impression of a substantial increase in meaningful data alongside a more developed understanding of the issues. However, whilst the knowledge base has certainly improved, closer scrutiny of the ‘new’ information reveals that much of it builds on similar and very provisional data sources, and accordingly represents only a small improvement in the robustness of earlier analyses.
Consequently, and despite there now being a much wider literature on shale gas, the earlier report’s cautionary note, “that a key issue in assessing… shale gas ... has been a paucity of reliable data”, still holds.
To date the only significant development and exploitation of shale gas has been in the United States (US). However, even there significant environmental issues remain unresolved, and reserve estimates show little sign of stabilising (increasing seven times in the last four years). Inevitably therefore, assessments of the environmental impacts, reserve potential and subsequently the greenhouse gas emissions for the European Union (EU) and the UK’s fledging shale gas sector, remain subject to significant levels of uncertainty.
In view of continued ambiguity as to the robustness of quantitative data, considerable effort has been made to ensure the veracity of the information in this report. Ultimately however, the analyses can only be as accurate as the information and the assumptions upon which it draws.
Despite these uncertainties, several clear conclusions arise and can be used to inform decisions on the appropriateness or otherwise of developing a shale gas industry within the UK. It is evident that shale gas extraction does not require the high energy and water inputs at the scale of other unconventional fuels, such as oil derived from tar sands. Nevertheless, there are several routes by which shale gas extraction may pose potentially significant risks to the environment. Concerns remain about the adequacy of current UK regulation of groundwater and surface water contamination and the assessment of environmental impact. Although amenable to stringent regulatory control, risks of contamination cannot be fully eliminated.