Feeds

Wind power: Even worse than you thought

But your 'leccy bill will keep going up to buy more of it

Choosing a cloud hosting partner with confidence

A new analysis of wind energy supplied to the UK National Grid in recent years has shown that wind farms produce significantly less electricity than had been thought, and that they cause more problems for the Grid than had been believed.

The report (28-page PDF/944 KB) was commissioned by conservation charity the John Muir Trust and carried out by consulting engineer Stuart Young. It measured electricity actually metered as being delivered to the National Grid.

In general it tends to be assumed that a wind farm will generate an average of 30 per cent of its maximum capacity over time. However the new study shows that this is actually untrue, with the turbines measured by the Grid turning in performances which were significantly worse:

Average output from wind was 27.18% of metered capacity in 2009, 21.14% in 2010, and 24.08% between November 2008 and December 2010 inclusive.

In general, then, one should assume that a wind farm will generate no more than 25 per cent of maximum capacity over time (and indeed this seems set to get worse as new super-large turbines come into service). Even over a year this will be up or down by a few per cent, making planning more difficult.

It gets worse, too, as wind power frequently drops to almost nothing. It tends to do this quite often just when demand is at its early-evening peak:

At each of the four highest peak demands of 2010 wind output was low being respectively 4.72%, 5.51%, 2.59% and 2.51% of capacity at peak demand.

And unfortunately the average capacity over time is pulled up significantly by brief windy periods. Wind output is actually below 20 per cent of maximum most of the time; it is below 10 per cent fully one-third of the time. Wind power needs a lot of thermal backup running most of the time to keep the lights on, but it also needs that backup to go away rapidly whenever the wind blows hard, or it won't deliver even 25 per cent of capacity.

Quite often windy periods come when demand is low, as in the middle of the night. Wind power nonetheless forces its way onto the grid, as wind-farm operators make most of their money not from selling electricity but from selling the renewables obligation certificates (ROCs) which they obtain for putting power onto the grid. Companies supplying power to end users in the UK must obtain a certain amount of ROCs by law or pay a "buy-out" fine: as a result ROCs can be sold for money to end-use suppliers.

Thus when wind farmers have a lot of power they will actually pay to get it onto the grid if necessary in order to obtain the lucrative ROCs which provide most of their revenue, forcing all non-renewable providers out of the market. If the wind is blowing hard and demand is low, there may nonetheless be just too much wind electricity for the grid to use, and this may happen quite often:

The incidence of high wind and low demand can occur at any time of year. As connected wind capacity increases there will come a point when no more thermal plant can be constrained off to accommodate wind power. In the illustrated 30GW connected wind capacity model [as planned for by the UK government at the moment] this scenario occurs 78 times, or three times a month on average. This indicates the requirement for a major reassessment of how much wind capacity can be tolerated by the Grid.

Remote control for virtualized desktops

More from The Register

next story
FORGET the CLIMATE: FATTIES are a MUCH BIGGER problem - study
Fat guy? Drink or smoke? You're worse than a TERRORIST
Renewable energy 'simply WON'T WORK': Top Google engineers
Windmills, solar, tidal - all a 'false hope', say Stanford PhDs
Rosetta probot drilling DENIED: Philae has its 'LEG in the AIR'
NOT best position for scientific fulfillment
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
HUMAN DNA 'will be FOUND ON MOON' – rocking boffin Brian Cox
Crowdfund plan to stimulate Blighty's space programme
Post-pub nosh neckfiller: The MIGHTY Scotch egg
Off to the boozer? This delicacy might help mitigate the effects
I'M SO SORRY, sobs Rosetta Brit boffin in 'sexist' sexy shirt storm
'He is just being himself' says proud mum of larger-than-life physicist
NASA launches new climate model at SC14
75 days of supercomputing later ...
LIFE, JIM? Comet probot lander found 'ORGANICS' on far-off iceball
That's it for God, then – if Comet 67P has got complex molecules
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
Getting started with customer-focused identity management
Learn why identity is a fundamental requirement to digital growth, and how without it there is no way to identify and engage customers in a meaningful way.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Choosing a cloud hosting partner with confidence
Download Choosing a Cloud Hosting Provider with Confidence to learn more about cloud computing - the new opportunities and new security challenges.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.