13 Mar 2015
Fracking is a hot topic which explains why one hundred attendees including current SCI Honorary President, Paul Booth, chairman of SABIC UK Petrochemicals, turned up to hear Professor Michael Stephenson discuss the facts and factoids surrounding shale gas and hydraulic fracturing at SCI's 'Shale gas and fracking: the science behind the controversy' Public Evening Lecture.
Mike began the event by providing background information describing how shale gas is formed and what hydraulic fracturing (fracking) involves. Shale, a very common rock, is hardened mud that forms over hundreds of millions of years. It contains 10% organic matter which comes from a variety of sources including ancient woods and algae. Gas is formed but becomes stuck inside the mud and it cannot be moved unless it is fractured. Fracturing therefore involves pumping water at 700 Atmospheres (a bathtub of water every second) into the shale which causes cracks in the mud and the gas is released.
The main focus of the lecture was for Mike to discuss two major, and quite different, questions surrounding the controversy: Do shale gas wells contaminate groundwater? Is shale gas 'lower carbon' than coal? In order to answer these questions the audience were provided with an exploration of peer reviewed papers. According to Mike, 'the peer review process is the best way to look at contested issues'.
Do shale gas wells contaminate groundwater? One paper looked at the historical records of methane in Marcellus, Pennsylvania – Pennsylvania has the greatest concentration of shale gas wells in the USA. The authors found evidence of thermogenic methane in ground water however it was not near to the fracking sites. Another paper studied methane concentrations in water wells in part of Pennsylvania and found that thermogenic methane levels are six times higher for water wells within 1km of fracking sites.
Is shale gas 'lower carbon' than coal? The arguments for and against this question are due to the facts that natural gas produces half the amount of CO2 than coal which is why shale is an attractive option, although there is concern that fracking releases methane into the atmosphere which is a more potent greenhouse gas than CO2. The first paper found that 3-8% of methane, in the lifetime production of a shale gas well, is released into the atmosphere. This large amount would indicate that shale gas wells might be adding a lot of greenhouse gas to the atmosphere. On the other hand, a second paper found that methane leakage is actually less than 1% and would therefore not be so harmful.
Mike concluded the lecture by stating that yes ground water is contaminated in parts of Pennsylvania by shale gas wells. However in other areas of the USA ground water is not contaminated. It is also true that shale gas burnt in power stations produces lower carbon emissions than coal; however further atmospheric measurement experiments need to be conducted. Shale gas as an energy source has attracted much controversy, there is need for a more reasoned and scientific approach to assessing the risks and advantages. However one fact remains: since 2009 shale gas production has dramatically increased and now provides a third of US domestic natural gas production.
The lecture ended with a question session and Mike mentioned that his new book Shale gas and fracking: the science behind the controversy is now available.
Jeffrey Powell, a member of SCI's Board of Trustees and pictured above right with speaker Mike Stephenson explained, 'SCI has recently established its new Energy Group. The Group will address some of the most crucial issues facing our society through SCI's Landmark Programme. Mike Stephenson's lecture on shale gas exploration provided an excellent backcloth to its first programme which is about 'energy choices: science and planning versus rhetoric and crisis'. Specifically, Mike Stephenson's lecture identified the contrary issues that need to be considered if shale gas is to be regarded as an economically and environmentally acceptable form of energy supply for electricity and heat.' If you would like more information regarding the new Energy Group then please contact communications@soci.org.
Becky Rivers,
Wiley
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