Generating heat and electricity from natural gas from shale produces greenhouse gases like all fossil fuels, although it does produce about half as much CO2 to generate electricity as coal.
However, we also must consider the effects of shale gas escaping into the atmosphere when it is being extracted. Shale gas is mostly methane, which is more harmful to the environment than CO2. According to the US Environmental Protection Agency “Pound for pound, the comparative impact of methane on climate change is over 20 times greater than CO2 over a 100-year period.”1
Therefore, to ensure the effect on the environment is minimised, it is very important that as much of the gas extracted as possible is used and that as little methane as possible escapes into the atmosphere. The Government’s Department of Energy and Climate Change (DECC) insists that operators must minimise the release of gas into the atmosphere and, when gas can’t be economically used, it must be captured and “flared” to reduce its global warming emissions.2 Beyond exploration, operators will have a commercial incentive not to flare gas, as the gas could otherwise be sold.
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