Why the Times doesn't believe the UK has fifteen centuries of shale gas

  • 11 Feb 2013, 16:00
  • Robin Webster

Bits of a report on the amount of shale gas lying under the UK keep leaking out, and the estimate seems to grow each time. On Saturday, the Times suggested the number will be 200 times larger than the BGS's previous estimate - giving the UK enough shale gas to heat every home for the next 1500 years.  

A big estimate  

The leaked numbers apparently come from a survey of the amount of shale gas under the UK, commissioned by the Department for Energy and Climate Change (DECC) from the British Geological Survey (BGS) last year.

The Times reports BGS's estimate for the amount of shale gas under the UK  "is understood to have increased dramatically" from 5.3 trillion feet to somewhere between 1,300 trillion and 1,700 trillion cubic feet. To provide a bit of context, the biggest gas field in the world is 1,235 trillion cubic feet. 

All in all, if the estimate were true, it sounds like a pretty dramatic figure. 

It's not the first time the Times has published a story based on leaked figures from the BGS report, so presumably it had a useful source somewhere. DECC and BGS wouldn't comment today on whether or not the figure is correct - or when the report is likely to be released - so it is hard to interrogate the figure further. Apparently it the figure itself is shrouded in secrecy within BGS. 

Enough to heat all the homes in the UK for fifteen centuries 

Whether or not the Times's figure is correct, it's certainly had some creative fun with the numbers. The first line of the article says that the new figure could mean that Britain "has enough shale gas to heat every home for 1,500 years". 

We weren't quite sure how this was worked out, so we decided to have another go at the calculation. The Energy Saving Trust told us that the average gas-heated home in the UK consumes approximately 47,000 cubic feet of gas. There are 26.4 million households in the UK. 

So if we make two (rather large, and clearly inaccurate) assumptions that the number of households in the UK and the amount of gas they consume don't change over the next fifteen centuries, then just over 1800 trillion cubic feet of gas would be needed to heat all the UK's home with gas for 1500 years. 

The Times has probably used slightly different figures from us, but the Times article's author, Tim Webb, told us that he used the upper end of the leaked BGS estimate - 1,700 trillion cubic feet - as the basis for its statement. 

But as the article itself points out, it won't be possible - technically or economically - to extract all the shale gas lying under the UK. The Times says up to a fifth - or 16 - 20 per cent - of the UK's onshore shale gas resource should prove recoverable - and even this is quite a high-end estimate for extraction rates. 

BGS has previously said extraction rates in the USA are " typically around 10 per cent". In addition, both BGS and DECC were at pains to point out to us today that it's too early to tell how extraction will pan out in the UK. 

It may be that the Times has more insider information from its industry contacts, however, so it may be right that the extraction rates are higher over here. 

Big numbers don't need inflation 

The Times's claim that "Britain could have enough shale gas to heat every home for 1,500 years" is presumably meant to be illustrative - not a prediction of what might happen over the next fifteen centuries. 

But it's not particularly clear that the estimate refers to the amount of shale gas in the ground, rather than amount that the UK might actually be able to use. And the headline adds to the confusion by simply announcing that "Britain has shale gas for 1,500 years".

In any case, these figures seem large, and even the prospect of heating the UK's homes for a couple of centuries is pretty mind-boggling. Perhaps numbers of this size don't really need confusing calculations laid on the top of them to make them any more impressive. 

Whether or not the BGS figures cited in the Times article prove to be true and how much of the gas it will prove possible or economical to extract, we have yet to find out. 

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