Most wind turbines' output could be boosted by changing rotational direction - study

The energy output of most wind turbines around the world could be increased by changing their direction of rotation from clockwise to anti-clockwise, a study conducted by the German Aerospace Centre (DLR) has found. While most turbine makers have opted for a clockwise rotation under the assumption that the rotational direction is irrelevant for the amount of energy each installation can produce, the DLR study, seen by Clean Energy Wire, showed that there is indeed a difference if turbines are built in clusters, which is usually the case as these are generally packed together in wind farms. According to the DLR, slipstreams that occur as the airflow is passed on from the first turbine to the next ones built behind it mean a staggered array of turbines rotating in either direction could, at least in theory, increase the output of rearward turbines by up to 23 percent. Due to inertia caused by the so-called Coriolis force, the effects described in the study are much stronger in the northern hemisphere, where the vast majority of all turbines in operation are built. They also tend to increase during the night and are strongest at locations with a steady and unobstructed wind flow, for example on plains or at sea, the study found, which was first reported on by Tagesspiegel.

About 30,000 onshore wind turbines were in operation in Germany as of 2019. They form the most important pillar of the country's renewable power supply. Licensing difficulties and protests against individual projects have hampered the technology's expansion in the past years, even though wind power generally continues to enjoy a very strong backing among the population. Wind power showed its potential in the first three months of 2020, when renewables for the first time covered more than 50 percent of Germany's power production and onshore and offshore wind together contributed over one third.