Emmanuel Macron was careful not to mention the subject during his last trip to Saint-Nazaire. And yet, while France wants to go into overdrive in terms of wind turbines, with 50 parks installed by 2050, scientists are wondering if we will have a lot of wind in the future. The year 2021 has already resulted in an exceptional air pocket due to the anticyclonic conditions present in Northern Europe. Thus, in the United Kingdom, Ireland, Germany and Luxembourg, the speed of air currents at an altitude of one hundred meters – the height of wind turbines – has decreased by 10 to 15% compared to usual averages. For the United Kingdom, it is even one of the worst results of the last sixty years. With concrete consequences: wind power generation, which represented 18% of the energy mix, saw its share fall to… 2% in September 2021.
“Preliminary data seem to show that the year 2022 will be more within the norm,” said Julien Nicolas, scientist at the European Center for Medium-Range Weather Forecasts (ECMWF). This means that air currents will be stronger on average this year. However, the risk for the future is that climate change will gradually weaken the machine for creating gusts. “The difference in temperature between the tropics and the poles is the main wind driver on a planetary scale. However, as in the northern hemisphere, the Arctic is warming up faster than the rest, the temperature gradient between the two zones is reduced. We could therefore have less wind in the future”, confirms Julien Nicolas.
IPCC experts already mention this risk in their latest report. However, they will need time to confirm this hypothesis: “The situation is not as clear as some say, wishes to specify Fabio D’Andrea, research director at the CNRS and deputy director of the dynamic meteorology laboratory at the École Upper Normal (ENS).Although the surface wind has slowed in recent times, in recent years there has been an acceleration of air currents at higher altitudes.Furthermore, not all studies conclude in the direction of weakening of the wind.”
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It’s written in the dust… of the Pliocene era
Certainly, after examining the dust deposited on Earth during the Pliocene era – when temperatures and carbon dioxide levels were similar to what they are today – some scientists estimate that the prevailing winds will be weaker at the future. But other recent works, focused on the United States, anticipate contrasting developments with a decrease in winds over the western part of the country as well as on the east coast, and an acceleration in the center.
In France, the lights are still far from turning red. Last year, the wind speed only decreased by about 4%. A figure much better than that of neighboring countries located further north. However, the network operator RTE mentions the problem of wind in its latest report: “The transformation of the electricity system must now integrate the probable consequences of climate change, in particular on water resources, heat waves or wind”, he says without further details.
“What we saw in 2021 could have been anecdotal twenty years ago. But today, we are increasingly dependent on renewable energies. We must therefore follow this theme closely”, comments Julien Nicolas. If the lack of wind is confirmed, electricity producers will soon suffer the consequences, including in France. First of all, there is a threshold below which the wind turbines no longer turn. Then, the output of a wind turbine is a cubic function of the wind speed. In other words, even a small decrease in bursts can lead to a noticeable drop in yields. Some British experts have already done their calculations: a 10% drop in wind could result in a 30% drop in wind power generation. What seriously complicate the economic equations of the sector.
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