Fracking by Numbers

Part II of a series on High Volume Well Stimulation, or ‘fracking’…

At a training and strategy event organised by Friends of the Earth (see Part I, here) I’d heard some of the concerns and objections to fracking, but I had yet to make up my mind on the subject. In fact, that’s still the case. On the one hand, the natural gas would be very useful to a nation that’s just beginning to suffer from quite a bad hangover as the party that was North Sea oil and gas winds down. Against this, it’s a fossil fuel energy source (so it’s finite, and a contributor to climate change) and the methods used for extraction are causing people anxiety for a number of reasons.

If I’m going to come down off the fence on this important issue, I’m going to need to base my decision on evidence, and good science. That has called for quite a bit of research.

One thing that I learned early on came as a surprise: that fracking appears to have been common in North Sea oil and gas extraction since the 1970s, and has been used onshore about 200 times in British oil and gas wells since the early 1980s. I should clarify that its use when going after shale gas is relatively recent.

Now, fracking can cause earthquakes. This particularly well-known ‘smoking gun’ in the case against fracking comes from two earthquakes that occurred in April and May of 2011, close to the Cuadrilla Resources’ Preese Hall drilling site near Blackpool, UK. They were of magnitude 2.3 and 1.5 respectively. To people who live in an area not known for its earthquakes, that sounds pretty scary. We know what an earthquake of magnitude 6.3 did to the beautiful city of Christchurch, New Zealand, in the same year. People (including the news media) need to understand, though, that the Richter magnitude scale is a base-10 logarithmic scale; thus a 4.0 wouldn’t be twice as bad as a 2.0, but a hundred times as bad. The two Blackpool earthquakes were tiny. (Cuadrilla’s Mark Miller was on the BBC in November 2011: see what you think of his assessment here.)

Independent newspaper: Blackpool earthquake

The Independent, June 1st 2011

A fact in favour of fracking is that the burning of natural gas has less potential to cause climate change, if the alternative is burning coal. I looked up DEFRA’s carbon dioxide conversion factors in an effort to get a definitive figure here. Using net calorific value in an effort to compare like with like I learned that the greenhouse gas emissions (expressed in kg CO2e per kWh, including the emissions resulting from extraction, transport, storage and so on) for natural gas are 0.22674 kg CO2e/kWh. In comparison, coal-fired electricity generation comes in at 0.39988 kg CO2e/kWh… which is to say 75% higher.

Liquefied natural gas (LNG), tankered in from elsewhere, is associated with emissions of 0.27750 kg CO2e/kWh, which argues that using locally-produced gas is the better choice, all other things being equal. What a shame that DEFRA currently make no distinction between gas obtained by conventional and unconventional means. I believe that gas produced via a fracking operation would have a somewhat greater carbon footprint, given the technology involved and the energy that must be invested before gas flows; more CO2e per kWh out. Exactly what the figure might be, I have not been able to determine, but if fracking takes off in the UK I bet that a future edition of the DEFRA conversion factors will include it – and I very much doubt that it will approach the climate change potential of coal. (We know that with cheap shale gas edging out coal in the USA, that country’s greenhouse gas emissions have fallen – something that Kyoto, Copenhagen, Cancún, Durban, Doha and all the other talks failed to do.)

A problem with any calculation based purely on greenhouse gases released, of course, is that it says nothing about other issues related to gas exploration such as traffic congestion, impacts on the tourist trade, water consumption, concerns about toxicity, etc.


Gasland, a 2010 independent documentary, prompted a lot of dialogue about fracking… but it’s no less biased than the industry’s own efforts. Who do you believe?

“Once you frack, you can’t go back,” one of the activists I met had warned me. To hydraulically fracture a shale bed you use a fluid that’s perhaps 90% water, with the bulk of the remainder being proppants (the material injected to hold fractures open; originally sand, but sometimes something more exotic such as sintered bauxite or zirconia silicate), and certain chemicals. It’s typically the chemicals that have the activists up in arms, and it’s true that there have been a bewildering number of different ones employed in the USA – although those available for use in the UK are significantly reduced by legislation. It seems that exactly which chemicals are used, and what happens to them afterwards, will be a major determinant in the acceptance (or not) of fracking in the UK.

That’s about as much as I had learned before yesterday. Last night I attended a talk by John Midgley of Energy Geoscience International Ltd., hosted by the Craven & Pendle Geological Society, and learned some interesting things about the history and science of fracking – which I’ll share in part III.


One thought on “Fracking by Numbers

  1. Pingback: Fracking: an Inside Story | Capacify

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