How long will shale gas keep our gas flowing?

A dozen or so hydraulic fracking companies have been granted licences to mine parts of the Bowland-Hodder shale deposits between one and three miles beneath the English Midlands. Two of these - iGas and Cuadrilla - have both recently raised their estimates of the volume of gas trapped in the shale they have been licensed to mine (often called 'gas-in-place'), They now believe it to be around 170 trillion* cubic feet (tcf) and around 200tcf respectively. These estimates correspond approximately to the recent 'most optimistic' gas-in-place estimates for the whole of the Bowland-Hodder shales (as opposed to just iGas's and Cuadrilla's shares) published by the British Geological Survey (BGS).

For fun then, if iGas and Cuadrilla were indeed sitting on 370tcf of gas-in-place, and that was the UK's sole source of gas, how much gas might they eventually pump out profitably and, how long would it keep the country's gas grid flowing? 

When assessing a shale deposit's potential for gas there are three key questions:

• How much gas is the deposit likely to contain (often called 'gas-in-place')?
• How much of it will be technically recoverable?

and the all important question

• How much of it will be profitably recoverable?

Independent experts estimate that between 10% and 30% of the gas-in-place in Bowland-Hodder shale mine will be recoverable given current technology. As the UK's geology is regarded as relatively difficult to mine, BGS predicts that:

• the proportion found to be technically recoverable will probably be much nearer 10% than 30%, and
• only around 3% of iGas and Cuadrilla's claimed likely total gas-in-place (370tcf) will turn out to be profitably recoverable

The sum would be: 

370tcf gas-in-place x 3% profitably recoverable

= 11tcf profitably recoverable gas 

Given that ...

• both iGas and Cuadrilla are touting for business and tax breaks from the UK Government and
• as Greenpeace chief scientist and policy director Doug Parr observed, "deciding likely UK shale gas reserves based on the word of shale gas firms is like buying a second-hand car without lifting up the bonnet and asking the price"

… it might be safer and more informative to be guided by the objective, expert estimates of BGS. 

The recent BGS re-estimation of the likely total gas-in-place in the entire Bowland-Hodder shales¹ (of which the iGas and Cuadrilla sites are but a part) gives two estimates:

•  An estimate of the gas-in-place in the upper layer of shale that, it explains, is (i) geologically very similar to the shale currently being mined in the US, (ii) easier to mine, and (iii) easier to estimate gas-in-place. It estimates this at between 164tcf and 447tcf

•  An estimate of the gas-in-place in the lower layer of shale that, it explains, is difficult to estimate accurately due to the lack of data (i.e. it remains largely undrilled). It offers a cautious estimate, nevertheless, of between 658tcf and 1,834tcf

Combined, therefore, its cautious estimate of likely total gas-in-place in the entire Bowland-Hodder shales is between 822tcf and 2,281tcf. 

BGS warns that insufficient data exists to give a reliable estimate of the proportion of the likely total gas-in-place that would be technically recoverable, let alone profitably recoverable. It does, however, compare the Bowland-Hodder shales in size and geology to the Barnett deposit in Texas (US) that, it says, "could potentially yield up to 4.7 tcf".
For even more fun then, let's be wildly optimistic (as one would never dare be if one was a Government minister developing an energy policy) and take BGS's most optimistic estimate of likely total Bowland-Hodder shales' gas-in-place (2,281tcf) and apply the tentative off-the-cuff, proportion of likely profitably recoverable gas from Bowland-Hodder extracted by torture from BGS (3%). 

The sum would be: 

2,281tcf gas-in-place x 3% profitably recoverable

= 69tcf profitably recoverable gas 

the equivalent of just over seventeen years current UK gas consumption - i.e. not a lot. Just time for four average UK Governments to come and go
And if, on the other hand, we took BGS's most cautious estimates (as one should do if one was a Government minister, etc.) the sum would be:

822tcf gas-in-place x 3%

= 24tcf profitably recoverable gas 

the equivalent of a mere eight years current UK gas consumption - and time for just two average Governments to come and go.

BGS is now re-estimating the likely total gas-in-place in the Weald basin, one of the UK’s other significant shale deposits. Its gas-in-place is currently thought to be around a nineteenth of that of the entire Bowland-Hodder shales.

Is it better as a country to throw ourselves behind fracking and shale gas for the equivalent of between eight and seventeen years of dirty, non-sustainable fossil fuel gas, or would it be better (in terms of energy policy) for the Government to focus its attention on developing increasingly efficient, non-polluting, sustainable ways of generating electricity, like wind, solar, hydroelectric and tidal power?

For the shale companies, of course, it will probably be highly profitable, so definitely worth it. For the UK Government it will probably mean (i) higher tax revenues despite the huge subsidies and tax breaks it is offering fracking companies (see the footnote below), (ii) the need to import less gas, increasing the UK's energy security, (iii) increased carbon dioxide and methane possibly increasing average global warming, and (iv) a higher burden on the NHS due to the chemical and radioactive environmental pollution that so far appears to be an inevitable part of fracking, 
so a mixed bag.

But as a nation of people who look forward to ...

• clean air, soil, water and food, and
• the day when we no longer depend on oil, gas and coal products

… is it worth it for us?

Footnotes and reference

It is probably illegal under EU law, but UK Chancellor George Osborne has already offered massive subsidies/tax breaks to any apparently responsible hydraulic fracking company prepared to mine in the UK. Those subsidies (all taxpayers' money) and tax breaks could have been invested in further developing wind or solar power, or in building pumped-storage hydroelectricity plants in Scotland (see 'The other half of windpower success' in Green Health Watch Magazine 44 page 9). 

* When the word 'trillion' was coined some time during the sixteenth Century it usually meant a million million million. By the 1970s the UK and US had adopted the 'short scale trillion' that we use now - a million million.

¹ Andrews, I.J. 2013. The Carboniferous Bowland Shale gas study: geology and resource estimation. British Geological Survey for Department of Energy and Climate Change, London, UK. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/226874/BGS_DECC_BowlandShaleGasReport_MAIN_REPORT.pdf

(16177)   Nick Anderson. Green Health Watch Magazine 45    (6.8.2013)