Government plans to generate all of Scotland’s electricity from renewables have been blown off course – by the summer heatwave.
Windfarm electricity output drastically fell away as a high-pressure system – bringing warm, settled weather – dominated the country for weeks. Critics called for a change of official government policy to prevent higher consumer prices and fears of the “the lights going out”.
New figures have revealed output from windfarms changed dramatically day-to-day over the summer. In June, turbines produced 1,044GWh (gigawatt hours) of electricity representing 4.7% of the total 22,335MWh (megawatt hours) input from all sources into the National Grid. In July wind was responsible for 726GWh, or 3.1%, of the total. And so far this month wind turbines have contributed 667MWh into the grid, or 5.1% of the total input.
Looking at days through summer, the output from turbines peaked and dipped considerably. On June 23, windfarms contributed 95,206MWh – but two days later the total fell to just 6,293MWh.
Over one week-long period at the height of the heatwave, output crashed. Total generation was 22,742MWh on July 21 – only to fall a 9,615MWh over the next six days.
Production has been so low that on Friday, one windfarm – Bilbster, near Wick – was generating enough to boil little more than 180 kettles.
Campaigners argue the sort of high pressure system – which kept temperatures around 30C last month – can happen in winter, when energy demand is high.
Stuart Young, of Caithness Windfarm Information Forum, said no one can say how much wind energy there will be at any given time. “Wind is the only generation technology that can be entirely absent. Over that we have absolutely no control.”
The Scottish Government has a goal of generating the equivalent of 50% of the country’s electricity from renewable sources by 2015 and 100% by 2020.
Wind power dominates the green energy mix. Output hit a record high last year, up 19% on 2011 and four times the levels reached in 2006.
Dr John Constable, director of the Renewable Energy Foundation, said the margin between generated and consumed electricity in the next few years will be “uncomfortably tight”. “There is a real risk that we are not going to have enough conventional generation,” he said.
He believes politicians are terrified of the lights going out and will probably have to take stop-gap measures, such as reopening closed coal power stations.
“That is what is so alarming. Politicians are blundering ahead, dogmatically attached to these policies, not thinking about the risk and the costs,” he said.
Jenny Hogan, of industry body Scottish Renewables, said a “diverse mix” of technologies was needed.
“It won’t come as a surprise to anyone that some days are windier than others. But it’s important to look at the average output for onshore wind over the entire year rather than snapshots of single days,” she said.
“Onshore wind in Scotland helps meet the equivalent of 22% of our electricity demand with other renewable technologies contributing a further 17%.”
A Scottish Government spokeswoman said renewable energy targets were “ambitious, but achievable”. “Renewable generation in Scotland was at a record high in 2012, meeting around 39% of our electricity demand,” she said.