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In 2021 parts of northwestern and central Europe saw some of the lowest annual average wind speeds since 1979. Across the entire year some regions showed drops of 10 per cent on previous years, while in the third quarter of 2021, the UK and Ireland's prevailing winds were 20 per cent slower than the annual average. The drop could be due to climate change.
Global winds are driven by temperature differences between the poles and the tropics. The larger the difference, the stronger the winds. According to a recent study, the Arctic has warmed four times faster than the rest of the world since 1979.
If the Arctic is warming faster than the equator, it's narrowing the temperature difference, which in turn is weakening the jet stream. Long-term trends in wind systems are difficult to detect, but the Intergovernmental Panel on Climate Change says that by 2100, average annual wind speeds could drop by up to 10 per cent. A drop in wind speed will result in a more significant drop in energy production, since power generated by wind turbines is proportional to the cube of near-surface wind speed.
If global stilling is occurring, infrastructure planning will need to be factored into the future of renewable energy. One measure could be to increase investment in floating wind turbines. These platforms can be anchored in deep waters far out to sea.
Nearly 80 per cent of the world's offshore wind resource is in waters deeper than 60 metres, which is too deep for fixed-bottom wind turbines. Floating turbines are currently more expensive than fixed ones, but costs are predicted to fall. Globally, wind power currently accounts for about 7 per cent of electricity generated, but future-proofing energy supply would mean diversifying further in areas such as solar, geothermal, and nuclear.
Another measure that would help smooth supply is building more electricity interconnectors, the high-voltage cables that link the grids of different countries, allowing energy to be imported and exported. Better energy storage options and applying long-term weather forecasting to the energy sector could also help. Net-zero targets will demand significantly higher levels of renewable energy, but if wind speeds do fall, without adjustments, attempts to hit those targets could be compromised.