Good news for wind farm operators: According to a study, the average wind speed on land in the northern hemisphere has risen by about seven percent in the past few years - from 3.13 meters per second in 2010 to 3.30 meters per second in 2017. This is a turnaround: between 1980 and 2010, wind speeds had fallen.
As the wind in the northern hemisphere now blows faster on average, the potentially exploitable wind energy increases by 17 percent, report researchers to Zhenzhong Zeng from Princeton University (New Jersey, USA) in the journal "Nature Climate Change". For a wind turbine in the Northeastern United States, the researchers even calculated an increase of 25 percent for the period 2014 to 2017 compared to the period 2009 to 2013.
For the analysis, the researchers had analyzed weather data from more than 1400 stations from the years 1978 to 2017, especially in the temperate latitudes of the northern hemisphere. In Asia, wind speeds have been increasing since 2001, in Europe since 2003 and in North America since 2012.
In ten years, wind speeds could fall again
One megawatt of wind power, according to the researchers compared to other energy sources reduce the carbon dioxide emissions by well over 1300 tons and also save about 2000 liters of water. Therefore, it is important to know how the changed wind speeds on land come about.
Scientists suspect that interactions between oceans and the atmosphere have led to rising wind speeds. The strength and temperature of currents in the oceans are constantly changing over the course of decades. They also affect the air temperatures at the sea surface and thus the differences in air pressure that cause the wind.
Zeng's team tested 21 such interactions between the oceans and the atmosphere. Wind speeds in Europe could have increased as a result of changes in the so-called North Atlantic Oscillation, in particular due to fluctuations in the pressure ratios between the Azores high and Icelandic low.
"We expect the trend of increasing wind speeds to continue over ten years," says researcher Zeng. After that, the wind speeds could decrease again. The researchers demand more accurate forecasts, so that the investment in wind turbines, which are usually twelve to 15 years in use, could be better calculated.
"Knowing about possible downward trends in wind speeds in the long term can be very useful for planning future wind power infrastructure," says Charles Meneveau, a professor of mechanical engineering at Johns Hopkins University in Baltimore, Maryland, USA Study was involved.
