Unpacking Christopher Booker’s wind vs coal comparison
UK energy policy is “collapsing”, says Christopher Booker, just like the cooling towers of closed coal-fired power station Didcot A in Oxfordshire. It’s an arresting image, but is it right?
Booker thinks we should be sticking with cheap coal-fired electricity instead of investing in wind power, despite the large carbon emissions and health impacts from coal-generated air pollution.
Wind versus Didcot A
Booker’s recurring theme is that wind power is a poor way to generate electricity, when compared to coal.
In order to rubbish it he presents a comparison with coal power. But it’s not easy to understand, and more importantly it may obscure more than it reveals about what’s actually going on with power generation in the UK.
Booker says:
“At the time when the plant’s German owners closed down Didcot A last yearâ?¦ the 2,000 megawatts of electricity it was capable of supplying to the National Grid were only slightly less than the average total of 2,200 megawatts then being unreliably generated by all of Britain’s thousands of subsidised wind turbines put together.”
It should be immediately clear that this argument uses a more favourable theoretical maximum for coal (“capable of supplying”) against a tougher, “in practice” amount for wind. But let’s pass over that for the moment, and treat the argument on its own merits.
The BBC reports that Didcot A closed down on 22 March 2013. That day, the average output from wind was 5,206 megawatts. That’s according to data from the UK National Grid Status website .
So on the day Didcot A closed down, wind generated more than twice as much electricity as the Oxfordshire coal plant could have done, if it had stayed open.
But that’s just for a day. What about over a longer time period? Looking at the whole month of March 2013, wind had an an average output of 2,150 megawatts a day. The theoretical maximum output from Didcot A operating 24 hours a day was 2,000 megawatts. So again, wind comes out on top – albeit not by much.
Capacity facts
Where then does the 2,200 figure come from? One final possibility seems the most plausible.
By the end of March 2013 the installed capacity of windfarms around the UK was 8,865 megawatts according to industry group Renewable UK.
On average, the UK’s windfarms generate around a third of their full capacity over the course of a year – because some days are windier than others. Onshore windfarms have a slightly lower capacity factor (29 per cent in 2013) and offshore slightly higher (39 per cent in 2013).
Applying a relatively ungenerous 25 per cent capacity factor to the combined total of onshore and offshore windfarms – the 8,865 megawatts – gives you a rounded down figure of 2,200 megawatts.
Which method is likely to produce a more informative view of the UK energy system? We’ll leave that up to the reader. Nevertheless, on the (presumably quite windy) day Didcot A was closed, UK wind was cranking out about twice as much electricity as the power station had ever managed.
Wind versus coal
Of course none of this changes that fact that coal currently generates much more electricity than wind in the UK. In 2013 coal generated 36 per cent of our power, compared with 8 per cent for wind.
It’s also the case that large, centralised power stations like coal, gas and nuclear plants generate relatively predictable ‘baseload’ power that – to a greater or lesser extent – can be switched on or off to match demand.
Nevertheless, the government clearly believe that wind power has a place in the UK’s electricity system – to say nothing of other European countries. Wind already generates a fifth of electricity Spain and a third in Denmark, for instance.
And it is equally true that coal power comes with a range of environmental and health impacts that other, cleaner sources of power do not.