Some gas extracted cannot be used, mainly during the exploratory stage. According to DECC’s licencing requirements, operators should work to minimise the release of gas. These requirements state that when it can’t be economically used, natural gas must be “flared” to reduce its global warming emissions’.1
Flaring, which is the controlled burning of gas, reduces emissions by up to 80% compared to venting, which is only used when absolutely necessary for safety reasons.
Beyond exploration, operators will have a commercial incentive not to flare gas, as the gas could otherwise be sold.
On behalf of the Department of Energy and Climate Change, Professor David MacKay, (DECC’s Chief Scientific Advisor) and Dr Timothy Stone (the Senior Advisor to the Secretary of State) have conducted a study into the possible impacts of shale gas extraction on greenhouse gas emissions. They found that “if adequately regulated, local greenhouse gas emissions from shale gas operations should represent only a small proportion of the total carbon footprint of shale gas2.”
Professor Richard Selley from Imperial College London said: “Release of gas into the atmosphere loses the operator money, and results in a financial penalty which means operators will want to minimise this. That said, without exploration, it is very difficult to know what proportion of the gas in a shale can be extracted and produced.”
Finally, the shale gas industry in the UK is developing “green completion” based on industry best practice, to reduce the emissions of gases into the air, and this is emphasised in UKOOG’s “UK Onshore Shale Gas Well Guidelines”3. This involves using specialist equipment to collect and separate the initial flow of water, sand and gas, so the gas can be prevented from escaping. According to Professor David MacKay, (DECC’s Chief Scientific Advisor), and Dr Timothy Stone (the Senior Advisor to the Secretary of State), “green completions” should be adopted at all stages following exploration.4 According to the Government’s Department of Energy and Climate Change “Green completions and flaring can reduce methane emissions by as much as 95% versus venting straight into the atmosphere.”5
3 UKOOG, UK Onshore Shale Gas Well Guidelines http://www.ukoog.org.uk/images/ukoog/pdfs/ShaleGasWellGuidelines.pdf