A new advanced control system for wind turbines, built by Energy Research Centre of the Netherlands (ECN) makes it possible to build larger wind turbines that produce up to 13% more energy. Tests carried out at the ECN wind farm using the system, which allows blades to be adjusted individually, show that the load on the wind turbine blades can be reduced by at least 20 %.
The construction of larger wind turbines can reduce the cost of wind energy and increase yields. However, the rotor blades of larger turbines are also subject to higher wind loads. Individual adjustment of the rotor blades can reduce this load, allowing lighter, cheaper wind turbines to be developed with a better financial return.
13 % more energy
ECN and wind turbine manufacturer XEMC-Darwind have designed a control system – based on Individual Pitch Control – that allows each of the three rotor blades to be controlled and adjusted individually. A computer programme constantly monitors the wind load and adjusts the positions of the blades accordingly. As ECN project leader Stoyan Kanev explains, ‘This means that you can produce the same amount of energy with a lower load. This makes it possible to design larger wind turbines with rotor blades that are more than 6 % longer and that can produce up to 13 % more energy.’
Tested and proven
The ECN Individual Pitch Control system was subjected to prolonged, large-scale testing on a wind turbine with a rotor diameter of 115 metres – the XEMC-Darwind XD 115. Testing took place at the ECN test farm in the Wieringermeer area, in accordance with the international IEC standard. Until now, such systems had only been tested in simulations. Kanev comments: ‘We tested it in an operational situation for two months and we proved that it works. We are incredibly happy with the results, which are even better than those obtained in the simulations.’ The 20 % lower load on the rotor blades translates into a higher energy yield.
FLOW research programme
ECN is continuously working on research and development aimed at reducing the cost and increasing the efficiency of wind turbines and wind farms. The advanced control system was developed as part of the FLOW research programme, in which 13 Dutch companies and knowledge institutions work together on innovative projects that aim to achieve cost reductions in offshore wind farms. Although the system was developed for offshore wind turbines, it can also be applied to wind turbines on land.