“From September 2016 an until December 2018, a special wind turbine was situated at DTU Risø Campus. It was a 4-rotor Concept Turbine from Vestas. The name refers to the fact that it has four rotors instead of the usual one rotor, which we know from most turbines of today.
The 4-rotor Concept Turbine was a part of research into whether the cost of wind energy can be more competitive by delivering a larger production of electricity and reducing the weight concurrently. Researchers from DTU Wind Energy contributed with counselling and metrological services.
The motivation behind the turbine was thus to reduce the cost of electricity. This was done by reducing the consumption of materials and using smaller components for the turbine. The smaller parts were visible at the small blades of the turbine. In general, through the last decades, turbines have grown larger resulting in bigger challenges regarding logistics and handling of the components. The larger the turbines are the more materials are being used.
In spite of the height of the concept turbine of just 74 meters, it had a capacity of 900 kW.
When doubling the size of a turbine, the area which the rotating blades are covering will get four times as big. In that way the electricity generation will increase fourfold. However, there is another side of the coin: The total weight of the blades is increasing as well as the weight of the other mechanical components. The increased weight comes from an increased material consumption resulting in higher total costs of the turbine. By constructing a turbine like the 4-rotor Concept Turbine with more and smaller components a lower weight is achieved, just as it gets easier to handle the turbine and the components.
This is an advantage e.g. when the components of the turbine are to be transported to markets where the necessary infrastructure has not been developed yet.”