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.