Can wind power credibly provide a significant contribution to Britain’s future energy needs?

Writing in the Sunday Telegraph over the weekend, Andrew Gilligan raised doubts, presenting a set of figures from scientific experts which questioned the amount the UK could ever hope to generate from onshore wind power.

The Claim

Mr Gilligan referenced the work of Cambridge Professor and now Government Scientific Adviser on Energy , David Mackay to back up his argument about the amount wind can contribute to UK energy generation.

Discussing whether it is possible to overcome the intermittent nature of wind power to make it a reliable contributor to UK energy needs, Mr Gilligan stated:

“The wind turbines required in Britain alone, says Prof MacKay, would amount to about double the number of all turbines in the world. Even then, “the maximum plausible production from on-shore windmills is 20 kilowatt hours per day per person”, about a sixth of Britain’s actual consumption.”

This is quite a statistic – but what are the facts that led to this claim?

Analysis

The quote from Professor Mackay comes from his book ‘Sustainable Energy Without the Hot Air’, in which he calculates that given the amount of energy produced by a turbine and the amount of space available to build turbines in the UK, the most that the machines could ever hypothetically generate in the future by the UK is 20 kilowatt hours per day per person.

This, the book argues, would require an onshore wind energy capacity in the UK of 150 Gigawatts (GW).

Professor Mackay points out that this is in fact double total world wind power capacity of 74 GW, as recorded by the World Wind Energy Association (WWEA).

Yet the problem is that the claim comes from calculations are based on 2006 levels.

Using the same data from the World Wind Energy Association cited by Professor Mackay , it can be seen that in 2009, world capacity had in fact doubled to 159GW and was projected to top 200GW in 2010. The WWEA figures estimate that UK capacity in 2009 was calculated as around 4 GW

The other variables used by Professor Mackay, namely population density and the amount of power generated by wind turbines, are extremely unlikely to have changed by the same degree, meaning the claim would no longer apply.

We contacted Professor Mackay to establish if this was a fair presentation of the claim and he told us: "The world total wind power is changing every year, and my comparison was from 2006 stats. I agree that world capacity is much bigger now, so the comparison would need to be rewritten."

Thus while the original calculations to which the article refers stand up, the use of them in 2010 has the potential to give the wrong impression to readers.

The use of the present tense when attributing quotes taken from Professor Mackay’s book suggest the numbers are much more current than they are.

 Full Fact contacted Mr Gilligan about the time lag in the figures, and he pointed out that Professor Mackay’s book was not actually published until 2009.

Conclusion

While the eye-catching statistic may have passed its sell by date, the wider point made by both Professor Mackay and Andrew Gilligan is valid. A vast expansion of onshore wind farms will be required if the Government does seek to boost the contribution made to UK energy output by wind power still stands.

Even then, the figures suggest there is a limit to what wind turbines can deliver.

We spoke to Renewable UK, the body representing wind energy producers, who acknowledged that with wind turbines operating within their capacity a huge expansion of turbines would be required in order to meet Government targets.  On the last Government’s assessment, EU targets would require the UK to generate between 30 and 40 per cent of its electricity from renewable sources by 2020, much of which would be wind.

“By the end of the year we’ll be getting about 4 per cent of our energy from wind,” a spokesman said.

Obviously we need more turbines there’s simply no other way.”

 

Patrick Casey