Wales’ burgeoning wind farms could be producing far less energy than supporters claim, a new report has suggested.
A two-year study – based in Scotland – by wild land conservation charity the John Muir Trust, concluded that many wind farms were operating at just 10% of their capacity for a third of the time.
The study also found that low output sometimes coincided with periods of peak demand.
However green energy experts claim the figures were “not relevant”.
The report concluded that wind power “cannot be relied upon” to provide any significant level of energy generation at any defined time in the future.
Wales currently has 34 onshore wind farms in operation, two offshore farms, two onshore farms under construction (in Rhondda Cynon Taf and Neath Port Talbot) and another 13 that have gained planning permission.
One of those sites is the £2bn Gwynt y Mor offshore farm in North Wales, which will have 160 wind turbines around 10 miles off the coast near Colwyn Bay and Llandudno.
There are another 23 proposed sites in the planning stage, including an 84-turbine proposal at Pen-y-Cymoedd in Rhondda Cynon Taf and Neath Port Talbot.
Powys is also the site of 15 proposed new farms.
But the study found that for numerous extended periods of time, all the wind turbines linked to the National Grid mustered less than 20MW of energy – only enough power for 6,667 households to boil their kettles for a cup of tea. It also questioned industry assertions that wind turbines would generate an average of 30% of their capacity over a year. It found that average output from wind was 24.08% between November 2008 and December 2010.
Report author Stuart Young said: “Over the two-year period studied in this report, the metered wind farms in the UK consistently generated far less energy than wind proponents claim is typical.
“The intermittent nature of wind also gives rise to low wind coinciding with high energy demand. Sadly, wind power is not what it’s cracked up to be and cannot contribute greatly to energy security in the UK.”
The study also found that 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.
Kate Ashbrook, general secretary of the Open Spaces Society which campaigns against wind farms on rural land, said that the next Assembly Government needed to “rethink” its love of wind turbines.
“If the report is correct, that is all the more reason not even to consider desecrating the open hillsides of Wales,” she said. “They provide far greater value for recreation and refreshment and a greater boost for tourism for the people of Wales.
“The government needs to be clear about the science of wind energy, because if the John Muir Trust is right, then they have clearly got it wrong being so wedded to wind as a cost-effective form of energy.”
But Alex Randell, spokesman for the Centre for Alternative Technology in Machynlleth, Powys, said that while the numbers were correct, they were “not relevant”.
He said: “What they are saying is that wind turbines do not operate all of the times, they operate when the wind blows, but we already knew that.
“Wind turbines generate electricity for the grid when the wind blows, and when it doesn’t, it doesn’t – that is not particularly controversial.
“Have we gone down the wrong route in renewable energy? I don’t think so. Wind is the most tried-and-tested renewable technology we have and it has always been said that there needs to be a mixed approach.
“We have got to replace our current energy generation with something, given what we know about the climate, and it has to be something that doesn’t produce carbon – and wind is our most developed way of doing that.”
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