Warming by wind farms minimal

Climate impact remains very low in Europe even with double wind turbine density

Wind Farm: How strong is its climate effect? © DOE / Alstrom
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What climate effect do wind farms have? Are they even worried about additional turbulence heating? At least for Europe, researchers give the all-clear: even if twice the installed capacity by 2020, the effect on rainfall and temperatures will be minimal. It would only be measurable in winter and would be well below the natural annual fluctuation range, according to the scientists in the journal "Nature Communications".

In the last ten years, the output of wind turbines installed worldwide has increased tenfold. Europe is one of the regions with the highest density of such facilities. "But the development of wind energy raises concerns, " said Robert Vautard from the Laboratory for Climate and Environmental Research in Gif-sur-Yvette, France, and his colleagues. On the one hand, the production of wind power depends heavily on the weather and therefore fluctuates considerably. That has to be caught over the nets.

Heating by turbine turbulence

Wind turbines, however, have an impact on the climate and the environment in their environment. It was not until 2012 that a US study caught the eye and found that local wind farms in Texas were up to 0.7 degrees Celsius. Whether such a climate effect is to be feared also for Europe, Vautard and its colleagues have now determined for the first time.

For their study, they first created a climate model for Europe, in which the locations and performance of all installed until the end of 2012 wind turbines were implemented. Then they carried out three simulation runs: once completely without wind turbines, once with the status of 2012 and once with the forecast for the year 2020 density of wind turbines in Europe. In the simulations, the researchers examined how much the turbulences caused by the turbines influenced the local daytime and nighttime temperatures as well as the large-scale air mass movements.

Significant effects only in winter

The result: There is an effect, but this is much lower than previously thought. If the researchers compared the two extremes - the scenario without wind turbines and that for 2020, then significant differences could only be found for the winter. Thus, the wind turbulence induced atmospheric turbulence could distract the west from low pressure areas minimal north. This could lead to less rain or snow, especially in Western Europe in winter. display

However, these changes are extremely small, they only account for a maximum of 0.5 percent and therefore disappear into the normal annual fluctuations, as Vautard and his colleagues emphasize.

Local only a maximum of 0.3 degrees

The effect on the winter temperatures is limited. The researchers found a maximum change of 0.3 degrees Celsius auch and this only in very limited areas. "The wind turbines increase the turbulence in the stable boundary layers between air and ground, " explain Vautard and his colleagues. The reduced cold and fog near the ground and increase the incidence of radiation by a little.

However, these effects are also small compared to the normal annual fluctuations. In offshore wind farms, these climate effects were even lower than on land - probably because the air layers above the sea are more uniform. When these layers are mixed, not so much changes.

Overall, the study gives the all-clear: Even if the wind power in Europe is further expanded, nobody has to fear serious changes in the climate, so the conclusion of Vautard and his colleagues. All of the observed effects are significantly weaker than natural climate variability and are also well below the changes that further climate change will bring. (Nature Communications, 2014; doi: 10.1038 / ncomms4196)

(Nature, 12.02.2014 - NPO)