1,000 trillion cubic feet of offshore shale gas? “Don’t believe the figures,” says geologist
- 19 Apr 2012, 17:00
- Ros Donald
Reports emerged yesterday that the UK might have around 1,000
trillion cubic feet of offshore shale gas, a figure the
Wall Street Journal are attributing to the British Geological
Survey (BGS). But when we asked BGS, it told us it doesn't
recognise the estimate, or think that much gas will be recoverable.
So what's going on?
The Times wrote:
"Yesterday, the British Geological
Survey released estimates of Britain's offshore shale gas reserves,
exceed one trillion cubic feet, more than five times the
estimated onshore deposits, it said. This would catapult the UK
into the top ranks of worldwide producers of shale gas."
In 2011, BGS estimated the total onshore shale gas resource in
the UK at 144 billion cubic metres. It is currently in the process
of coming up with a new estimation for onshore
resource, but we didn't know anything about a new offshore
estimate. So it seemed a bit out of character for BGS to start
announcing offshore reserves of 1,000 trillion cubic feet off UK
On investigation, it appears this figure stems from a Reuters
report on Tuesday:
Exclusive: UK has vast shale gas reserves, geologists say.
Reuters quotes a BGS geologist, Nigel
"'There will be a lot more offshore
shale gas and oil resources than onshore,' [...] UK offshore
reserves could be five to 10 times as high as onshore[...]."
Smith made this statement to the
UK's energy and climate change committee in February 2011
during an investigation into shale gas.
But when we asked him whether he'd ever said the UK's
offshore reserves equalled 1,000 trillion cubic feet, Smith told
"Don't believe the figures!"
Shale gas company Cuadrilla last year
estimated the UK's onshore reserves at 200 trillion cubic feet.
"What [the reporter] has done, I think,
is take Cuadrilla's 200 [trillion cubic feet] resource and
multiplied by five."
The Cuadrilla figure is not uncontroversial either - an earlier
article describes BGS as "sceptical" about
it. Reuters seemed to realise this a bit late in the day, as a
later version of their report adds the caveat:
"[S]ome experts doubt preliminary
onshore reserve figures by private companies."
Smith advises further caution, saying there's big difference
between theoretical reserves and the amount of shale gas ultimately
"We would need to work out the areas of
different aged source rocks offshore and plug in some gas contents
and thicknesses to come up with a ball-park figure of this
theoretical resource. At current technology onshore US only 10% of
the resource is actually produced."
Reuters did mention this, but the Times and WSJ miss that bit
He added that although there are arguments in favour of UK
concentrating on offshore reserves - including energy security and
minimising potential harm to the public - the day when they are
exploitable is still far off. The UK will have to pioneer offshore
shale gas drilling because the US, the trailblazer in
unconventional gas, has not needed to look further than its onshore
It is possible, of course, that there is a significant amount of
shale gas offshore. A column in the
Economist suggests the UK government has pulled together its
own data that also suggests reserves could be significant. And
Reuters also claims that energy companies are getting excited about
larger than imagined shale gas reserves:
"Geologists at [...] leading energy
companies spoke on condition of anonymity due to the sensitive
nature of the dramatically higher estimates, but a consensus of
optimism about potential European reserves has grown in the
hard-headed commercial sector."
But these estimates don't come from the BGS.
There's another point that the UK will have to take into account
if it wants to meet its emissions targets. A column by pro-shale
Matt Ridley in the Times illustrates the difficulty the UK
faces in further cutting emissions if it goes for unconventional
gas wholesale. Ridley says:
"[S]hale gas has already cut carbon
emissions in a way that wind, biomass and solar power have failed
He cites a 7 per cent drop in US emissions in 2009 as "caused
largely by a switch to shale gas". There's an obvious
problems with his argument: the UK already derives the majority of
its electricity from gas, while shale gas in the US has displaced
coal-fired plants - as we explain
here. If, indeed, shale gas were to displace UK renewables,
that won't help us meet our