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Fracking earthquakes and flaming water: but not in the UK

Energy and Climate Change Secretary, Ed Davey, reignited the row over fracking this week, when he insisted this method of extracting shale gas was no “great evil” and could act as a bridge to a “green…

Drilling in Balcombe and in Lancashire, pictured, has caused a frack load of fuss. Cuadrilla

Energy and Climate Change Secretary, Ed Davey, reignited the row over fracking this week, when he insisted this method of extracting shale gas was no “great evil” and could act as a bridge to a “green future” in the UK so long as it was properly regulated.

The UK is thought to have significant reserves of shale gas which the government has encouraged the industry to exploit as the gas reserves from the North Sea decline.

Hydraulic fracturing, or fracking, is not new. It has been used to improve the permeability of rock around a well for many years in gas reservoirs where rocks are relatively impermeable. Fracking for shale gas differs only in scale, in that as the fractures are the only pathways for gas to move through the formation to the well, so they must be much more extensive.

This is done by injecting a watery brine of chemicals and sand under high pressure into the rock to create fractures along the length of long horizontally-drilled wells off the main well. These are well-established techniques, but they are used more extensively when tackling shale gas reserves.

What are the risks? Public concern has been raised by the two earthquakes in Blackpool and by health scare stories from the US where there has been evidence of water supply contamination and burning tapwater.

Fracking by its nature breaks the rock, and this creates seismic events. However, extensive monitoring and experience from the US in particular has shown that the fracking is unlikely to lead to harmful seismicity. The Royal Society and Royal Academy of Engineering investigated these risks and concluded that there was no risk from seismicity associated with fracking from suitably located wells in the UK. The Blackpool earthquakes were at the upper end of the range of expected seismicity, caused no harm, and were due to fracking wells close to an existing fault.

The second issue that causes alarm is the risk of pollution. The additives used to help the injection of the sand laden fracking fluids include hazardous substances. When the fracking is completed these fluids flow back under pressure to the surface via the well along with methane from the formation. Pollution has occurred when these fluids and methane have found their way into the drinking water aquifer (the layer of water-bearing permeable rock). US regulations do not require details of the commercial fracking fluid to be disclosed and the control of well completion is less rigorous than EU and UK requirements, and this has made it difficult to identify and control the pollution risks. The main way the fluids can directly pollute the aquifer is if the main well casings fail allowing seepage into the aquifer. But in the UK, the construction of these wells is tightly regulated and associated risks can therefore be managed.

Recent EU reports on the risks of exploiting shale gas across Europe identify the environmental risks, but conclude that these would be better managed by existing EU regulations than has been the case in the US. Guidelines in the Royal Society report identify a number of measures to ensure that wells are suitably sited, and propose monitoring requirements to spot any issues early and prevent water supply contamination.

Is it worth it? In the US, shale gas has replaced oil and coal with significant reductions in greenhouse gas emissions and has significantly reduced gas prices. In the UK, we are replacing depleted supplies of North Sea gas. There is no direct benefit in terms of green house gas emissions and it remains to be seen what the economic costs are, but if we do not take advantage of this energy resource, we face an even more uncertain energy supply over the coming years.

There are of course reasons why one might not like a gas production platform in your backyard, but the risks of it leading to methane in your tap water or to earthquakes are minimal.

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8 Comments sorted by

  1. Stephen Ferguson

    Software Engineer

    "shale gas has replaced oil and coal with significant reductions in greenhouse gas emissions".

    Sorry, but that's just an optimistic assertion that the industry is only too happy to see repeated.

    To back up such a huge claim there needs to be a large body of convincing objective, scientific evidence that fugitive emissions of - high-impact greenhouse gas - methane are extremely low. Unfortunately for those who make this oft-repeated assertion, such a body of evidence doesn't exist, indeed of the small number of such studies undertaken so far, a worrying number report the contrary e.g.

    .http://www.eeb.cornell.edu/howarth/web/Marcellus.html

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    1. Alan Herbert

      Senior Lecturer in Radioactive Waste Disposal and Remediation at University of Birmingham

      In reply to Stephen Ferguson

      As with any contentious issue, there are conflicting views! Howarth et al.'s analysis assumes that very substantial volumes of methane are vented during development of shale gas wells. This is refuted by others (http://www.geo.cornell.edu/eas/PeoplePlaces/Faculty/cathles/Natural Gas/Response to Howarth's Reply Distributed Feb 30, 2012.pdf), and is linked to industry practice. I would hope and expect that tighter regulation in the EU would avoid practices that might give rise to the very large fugitive emmissions suggested by Howarth et al. even if US regulation does not!

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    2. Stephen Ferguson

      Software Engineer

      In reply to Alan Herbert

      Alan, Thanks for replying. I'm no expert, but on my brief look this topic, it does indeed come across as a contentious issue - possibly made even more contentious by industry funding some of the US academic studies (e.g. the University of Texas one that just came out... http://www.climatecentral.org/news/study-fracking-emits-less-methane-than-estimated-16483) and, to be honest, what looks like something of a media PR campaign to rubbish the Howarth paper.

      Howarth et al. even fired back at the…

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    3. Stephen Ferguson

      Software Engineer

      In reply to Alan Herbert

      Alan,
      I got that link to work after all and see it was a rebuttal to Howarth et al.'s rebuttal! Thanks for that as I hadn't come across it before.

      My take on all this is that the jury is still very much out as demonstrated in this instance by academics from the self-same prestigious university unable to agree (albeit from different faculties). Moreover we are not dealing with settled science with a large body of evidence behind it (e.g. climate science), but with the environmental impact of a challenging new technology that requires a huge range of expertise (both scientific and engineering) to fully understand. Perhaps the Cornell disagreement comes about precisely because neither team have the huge breadth of knowledge required.

      Having said that I am still more convinced with Howarth's rationale for using the 'pessimistic' 20 year time horizon over that proffered by Cathles'

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    4. Alan Herbert

      Senior Lecturer in Radioactive Waste Disposal and Remediation at University of Birmingham

      In reply to Stephen Ferguson

      In case anyone else has problems with the link - it is the spaces that I left in... if the link is copied and pasted to a browser it works for me...

      As you see in the links, it is a contentious issues and there is no consensus here... The energy ROI and emissions to air are not my field (I work in groundwater), but for my part I would side with Cathles as he appears to have access to better data on industry practice. In my experience scientists are almost always honestly trying to discover the truth, based on the data they have available to them However we have our emotional preconceptions fears and hopes and so perhaps stop searching too easily when we make findings that support our ideas. The ongoing debate will in the end lead to a consensus on what the impacts are if not on whether they are acceptable!

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    5. Stephen Ferguson

      Software Engineer

      In reply to Alan Herbert

      Agreed on possibility of confirmation bias. I do wonder about the level of advocacy being expressed by the scholars involved. Ingraffea in particular makes no secret about his views and actively campaigns against fracking. And yet his credentials on the engineering are impeccable and cannot be lightly dismissed. Either way, as you say, it's early days and a consensus is yet to emerge. For that reason alone it is premature to claim that shale gas, indeed even any natural gas, is 'low-carbon' compared…

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  2. Andy Maybury

    logged in via LinkedIn

    The underlying problem that really needs to be tackled is the ROI or, more strictly, the energy return on energy invested.

    http://www.carbonbrief.org/blog/2013/03/energy-return-on-investment-which-fuels-win

    Fracking and 'unconventional' fossil fuels amount to scraping the barrel and it's not going to help much and certainly not for very long. Let's just bite the bullet and do what we should have been doing thirty years ago and develop clean sources of power.

    Good to know that we in Europe have managed to work out how to get the gas out of the rocks and into the pipes without any of it or the chemicals used getting into the water table even if it is involved in the same rocks.

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    1. Alan Herbert

      Senior Lecturer in Radioactive Waste Disposal and Remediation at University of Birmingham

      In reply to Andy Maybury

      Hi Andy,
      It used to be feared that we were approaching 'peak oil' and that when oil production could no longer keep up with demand there would be a catastrophic shock to the global economy. What is happening is rather that as the easy oil is exhausted, the price rises and makes unconventional oil and gas commercially viable. As soon as there is money to be made (with acceptable risk!) these resources will be exploited unless there is regulatory control to prevent it. Shale gas will be exploited…

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