Feeds

Wind power: Even worse than you thought

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

Build a business case: developing custom apps

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.

Boost IT visibility and business value

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Brit amateur payload set to complete full circle around PLANET EARTH
Ultralight solar radio tracker in glorious 25,000km almost-space odyssey
Boffins spot weirder quantum capers as neutrons take the high road, spin takes the low
Cheshire cat effect see neutrons and their properties walk different paths
NASA Mars rover FINALLY equals 1973 Soviet benchmark
Yet to surpass ancient Greek one, however
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.
Maximize storage efficiency across the enterprise
The HP StoreOnce backup solution offers highly flexible, centrally managed, and highly efficient data protection for any enterprise.