Could the Coldest Days Provide a Wind Power Boost?

World | Wind Energy

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A new study released yesterday suggests concerns about the impact the cold days have on wind power output may have been overblown, and provides new evidence wind power output exceeds the winter average on the coldest days.

The study, which involved scientists from the Met Office Hadley Centre, Imperial College London and the University of Reading, will be published in the journal Environmental Research Letters.

The report analyses wind power availability and electricity demand during the winter months.

Critics of wind energy have long argued that turbines struggle to provide power on the cold, still winter days when power demand across the UK is at its highest.

However, Hazel Thornton of the Met Office Hadley Centre said the study had provided evidence “contrary to what is often believed.

“During winter in the UK, warmer periods are often windier, while colder periods are more calm, due to the prevailing weather patterns,” she said in a statement. “Consequently we find that in winter as temperatures fall, and electricity demand increases, average wind energy supply reduces.

“However, contrary to what is often believed, when it comes to the very coldest days, with highest electricity demand, wind energy supply starts to recover.”

The research team found that during the highest five per cent of energy demand days, one third produce more wind power than the winter average.

“The very coldest days are associated with a mix of different weather patterns, some of which produce high winds in parts of the UK,” Hazel explained. “For example, very high pressure over Scandinavia and lower pressure over Southern Europe, blows cold continental air from the east over the UK, giving high demand, but also high wind power. In contrast, winds blowing from the north, such as happened during December 2010, typically give very high demand but lower wind power supply.”

The report suggests that a spread of turbines across Great Britain could exploit the varied wind patterns associated with the coldest days, and ensure renewable power can play a role in meeting peak winter power demand.

The report also suggests that during high demand periods offshore wind power provides a more secure supply compared to onshore, as offshore wind is sustained at higher levels.

“A wind power system distributed around the UK is not as sensitive to still cold winter days as often imagined,” said Professor Sir Brian Hoskins, of the University of Reading and Chair of Imperial College London’s Grantham Institute – Climate Change and the Environment. “The average drop in generation is only a third and it even picks up for the days with the very highest electricity demand.”

However, the report does highlight the risk associated with concurrent wide-scale high electricity demand and low wind power supply over many parts of Europe. It warns that in such a scenario neighbouring countries may struggle to provide additional capacity to the UK, when the UK’s own demand is high and wind power low.

Catherine Mitchell, Professor of Energy Policy at the University of Exeter, said the report was “a welcome reminder that renewables are a fundamental part of the solution, but are not able to fully solve the problem on their own”.

“Highlighting the potential issues that would be caused by over-reliance on supply of wind power, this research emphasises the value of flexibility in electricity networks, balancing out changes in both supply and demand to keep the lights on at the lowest cos,” she said. “There are numerous flexibility tools in use and many more in the pipeline – such as demand-side measures, interconnection and storage.

“Rolling out mechanisms to expand these in the UK, perhaps through the Clean Growth Plan, will unlock further progress in the decarbonisation of our energy system and help consumers realise the £8bn per year savings highlighted by the National Infrastructure Commission.”

The report came as National Grid issued its annual update revealing that it expects its spare capacity margin for this winter to increase to between 7.2 per cent and 9.9 per cent, compared to 6.6 per cent last year.

A number of newspapers and think tanks have repeatedly warned the UK’s increased reliance on renewables will lead to greater blackout risks throughout the winter months. However, National Grid, Ofgem, and the government have all insisted these concerns are overblown and there is evidence the UK can support significantly higher levels of renewables capacity without jeopardising grid reliability.

“The impeccable reliability of our own electricity network should give ministers confidence to open the market to a wave of technologies set to ease the energy revolution currently taking place,” said Mitchell.

Source: businessgreen.com