Out of date statistics make Christopher Booker's wind power maths a bit shaky
- 30 Jul 2012, 17:38
- Christian Hunt
Government plans to meet renewable energy targets are
unrealistic, argues Christopher Booker in
yesterday's Sunday Telegraph. But the statistics he's using to
back up his argument suggest that renewables aren't actually as
useless as he thinks.
Last week, the Department of Energy and Climate Change (DECC)
set out how much electricity the UK will have to produce from
renewables in order to meet 2020 EU renewable energy targets. We
need to generate 79 terawatt hours (TWh) of electricity a year from
renewables in 2017, and 108 TWh a year in 2020, DECC says.
But Christopher Booker argues that given how little electricity
wind power currently produces, such plans are hopelessly
"In 2010, the last year for which we
have figures, we used 378 TWh of electricity, of which only 10 TWh,
or 2.6 per cent, came from wind … [T]o meet that ... target within
eight years, almost all the increase would have to come from new
Newer energy statistics show growth in
Booker is taking figures from DECC's
2011 Digest of UK Energy Statistics (DUKES)
report, which provides UK energy statistics for 2010.
But although he says these are the most recent figures available,
the new edition of DUKES was published last week,
providing information on what happened in 2011.
These new figures show the year saw fairly significant growth in
the amount of electricity coming from renewable sources. The amount
of electricity generated by wind power rose from 10.2 terawatt
hours in 2010 to 15.75 TWh in 2011 - a rise of 5.53 TWh.
This made up much of a wider growth in renewable power -
renewables generated 34.4 TWh of electricity in 2011, a rise of
about 8.6 TWh compared to 2010.
(See page 135.)
So is meeting a 2020 target "out of the
Based on the 2010 figures which show that only 2.6% of UK
electricity came from wind power that year, Booker argues that
getting 30% of the UK's electricity from renewables by 2020 is just
But looking at the newer 2011 figures suggests this might not be a
particularly solid argument.
DECC says we need to be generating 79 TWh of renewable electricity
a year by 2017. According to our calculations, this would mean an
increase of about 8.92 TWh a year from 2011. Getting to 108 TWh by
2020 requires faster growth - 9.2 TWh per year.
The increase in renewable generation between 2010 and 2011 was 8.6
TWh, so the new DUKES figures actually show something approaching
this rate of growth.
Of course, whether this can be sustained is a complicated
question. It would probably be unwise to assume that because
electricity produced from renewables jumped by 8.6 TWh in a year
this will carry on whatever happens, and it's worth pointing out
that in relation to the 2020 target DECC says:
"the scale of the increase over the next
10 years represents a huge challenge and will require strong
contributions from all three sectors of electricity, heat and
32,000 Turbines? Probably not
Booker goes on:
"If 3,000-odd turbines produced 2.6 per
cent in 2010, then to meet the EU target would require something
like the "32,000 turbines" mentioned by Davey's predecessor Chris
Huhne just before he resigned. This would require us to build about
10 giant turbines every day for the next eight years. Regardless of
how many billions of pounds of subsidy might be thrown at this, in
practical terms it is quite out of the question."
Is this right?
The 32,000 figure appears to have originated
in a Sunday Times article based on
this DECC report. The DECC report doesn't contain
the number, and the Sunday TImes article doesn't provide any
details on how it was calculated. It doesn't appear that Chris
Huhne is the source for the number - he
told the Daily Mail that the actual number of
turbines built to 2020 is likely to be closer to 10,000, as
turbines get larger.
So how many wind turbines would it take to provide the extra 73.6
TWh of electricity a year DECC says we need to meet the 2020
We can work this out, roughly, as:
Electricity generated = Number of turbines x (Turbine capacity
x Load factor x Time)
Time is just the number of hours in a year - 8,760. Load factor is
the average percentage of maximum capacity at which a turbine
operates at, and turbine capacity is the power rating of an average
load factor for onshore wind is 0.27, and 0.37 for
offshore. According to Renewable UK, the generating
capacity of wind turbines currently being installed is about 2 MW
for onshore and 3.6 MW for offshore.
Plugging those numbers in, an extra 73.6 TWh would take either
another 15,600 onshore turbines, or 6,300 offshore.
In practice, the numbers are likely to be smaller. Offshore
turbines will continue to increase in size, meaning it will take
less to produce more power. Turbines will probably become more
effective - increasing their load factor. And other sources of
renewables will produce more power, reducing the amount of wind
turbines needed to hit a particular amount of renewably-generated
So the 32,000 figure looks pretty overinflated.
On gas, the man's got a point
Finally, Booker probably has a good point in the rest of his
article, where he talks about the government's gas plans.
It's hard to see how the government can be committed to gas power
and meeting carbon budgets when carbon capture and storage is still
an "unproven technology", Booker says, suggesting that relying on
gas will "drive a coach and horses" through carbon targets.
This is a reasonable point - and one that
we made ourselves, in slightly different terms, last
Update - Guy Newey of Policy Exchange gets
in touch to point out that the 32,000 wind tubrine figure is likely
informed by the DECC 2050 Pathways calculator
here. (If you hover over some of the wind options, you can see
suggested numbers of turbines.) This is a scenario for 2050, rather
than the 2020 that Booker is talking about.