The Active Wake Control system of the Energy research Centre of the Netherlands (ECN) is able to increase the electricity production of wind farms by 0.5 to 5 per cent. Additionally, it is expected that maintenance costs can be reduced with 3 per cent.
The technology has been tested on 5 wind turbines at ECN’s wind farm test site and the next step is to test the technology at an offshore wind farm. Through optimal positioning of the wind turbines, the patented system reduces the wake effects of turbulence. In a perfect line position, turbines produce 100 percent power, but also take a 100 per cent load on axes and blades. When placed behind each other, the upstream turbine still produces 100 percent power, but the capacity of the downstream turbines is reduced to 60 or 50 percent. On top of this, wake effects caused by turbulence increase their load to 110 or 115 per cent and maintenance costs rise proportionally. By changing the pitch angle and/or the yaw angle of the front turbine a few degrees, the turbulence is deflected/altered, thus reducing the load and increasing the power production of downstream turbines. ECN first used in-house developed simulation tools to test the principle of “Active Wake Control”, but did a full-scale test on five 2.5 Megawatt Nordex turbines and finally on scaled wind farm with ten 10KW turbines at its test site in the Wieringermeer in the Netherlands. All tests showed the same result: the wind farm’s power production was increased by 0.5 to 5 percent and the loads were significantly reduced.