The geological and environmental risks of coalbed methane, or CBM, extraction are discussed here.
CBM is a natural gas extracted from coal beds. Virgin coal seams in the UK have been investigated for their potential for CBM production. DECC has provided a useful overview of UK prospects.
The most advanced CBM development in the UK is at Airth in Stirlingshire, where Dart Energy has applied for planning permission to drill up to 14 boreholes. It intends to extract the methane by the simple process of dewatering the coal, that is, pumping out the water. In doing so, the methane, which is adsorbed onto the coal surfaces, is released and collected.
Dart Energy does not intend to hydraulically fracture, or frack, the coalbeds to increase production, although its predecessor company at the same site, Coalbed Methane Ltd, did so in early tests.
In August 2013 I wrote a preliminary review of Dart Energy's current proposals at Airth for Concerned Citizens of Falkirk (CCoF). This report has been superceded by my precognition and rebuttal prepared for the local planning appeal held at Falkirk in March 2014. I appeared as an expert witness for CCoF.
Dart Energy does not seem to understand the geology sufficiently well. The area to be developed abounds in geological faults, and the rocks overlying the coal seams do not provide a sufficiently impermeable lid to prevent methane and fluids escaping up to the groundwater. In short, the environmental risks are great.
I have summarised the fracking problem in my submission to the House of Lords economic affairs select committee, November 2013. This document was limited to 3000 words and no diagrams, so references and end notes are in a separate file.
Dart Energy review