Europe has seen unusually light winds in the summer and early autumn of 2021. The resulting slowdown in wind power production is being partially blamed for the current energy crisis. British energy company SSE reported it has produced some 32% less renewable power between April and September due to a dry and low-wind summer, one of the least windy in the UK and Ireland in the last 70 years. Ørsted, the world’s biggest offshore wind developer, reported a loss of DKr300m (€40m) from its wind farms.
While the wind drought is expected to be temporary, understanding changes in wind speed seems vital as countries continue to invest in wind energy. A study into the increasing sensitivity of power systems to climate variability suggests that long-term, year-to-year fluctuations should be taken into consideration more, especially as renewables continue to expand.
Climate change research tends to focus on temperature, but the implications go far beyond that. The most recent report by the UN’s Intergovernmental Panel on Climate Change expects that, in most regions, the mean wind speed will decrease as a result of climate change. Between 1979 and 2018, global mean land wind speed (excluding Australia) showed a reduction of 0.063m per second every decade.
Figures from Copernicus, the EU’s Earth observation programme, show that wind speeds have shifted in different ways in different parts of Europe, with northern European countries seeing faster winds now compared with 40 years ago, while central Europe has seen wind speeds diminish.
Even small differences in wind speeds could have a large impact on power output. The amount of electricity generated by a turbine is mostly determined by wind speed, and the power output will increase cubically with the speed. In other words: if the wind speed doubles, the power output will increase eight times.
Meanwhile, wind capacity is only growing. With 220GW of wind capacity already installed in Europe – and even more needed to reach net-zero emission goals – the recent wind drought highlights the need to take fluctuations in wind speed into consideration.