Vestas System Stops Wind Turbine Shadow Flicker

New technology produced by Danish wind power firm Vestas aims to counter the effects of shadow flicker - one of the most controversial aspects of wind energy collection.

Shadow flicker occurs as a result of the sun making shadows out of rotating wind turbine blades - shadows that, if passing over properties or businesses, can be a real nuisance for those living inside.

It's for that reason that wind turbine site planning steps can include ecosystemic studies that look at how, once erected, the turbines' shadows will fall on the surrounding land.

Vestas Wind Systems' response to this situation is its Shadow Detection System, which essentially calculates when shadow flicker is going to take place and stops the blades' movement until the sun has moved around to cast the turbine's shadow elsewhere.

Vestas Shadow Detection System

The Vestas Shadow Detection System uses four sets of parameters to makes its judgment, looking at the sun's position and angle, relative to the wind turbine, the distance between the wind turbine and nearby residential units, the distance between the tips of the turbine blades and the distance between the highest point reached by the blades and the ground.

From here, a linked software programme comes up with two, different shadow scenarios. One displays the worst possible shadow flicker that could take place, while the other displays what Vestas terms an ‘actual' shadow depiction, factoring in real-time data values such as what the weather's doing and the operational state of the turbine.

Turbine Shadow Flicker System

According to a Vestas official, more than 50 of the firm's globally-installed wind power arrays have now hosted trials involving the firm's turbine shadow flicker detection system.

In comments quoted by the New Scientist, engineer Bruno Lund Mathiasen, representing Vestas, explained what happens when a potential shadow flicker incident is forecast. "The turbine will be put in idle mode, which means we twist the blades so the rotor turns very slowly", he said, adding: "This stops any shadow flickering.

"Based on its calculation of the shadow effect, the system will decide by itself whether to put the turbine in idle mode or not."

Besides shadow flicker, another issue associated with wind turbines is military radar interference. As covered by Enviro News, in July this year, Vestas carried a stealth wind turbine trial involving technology designed to mitigate the radar disruption factor.

Image courtesy of Vestas Wind Systems A/S

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Companies supplying Wind Power