The new test facility with a multi-rotor turbine will be built at Risø near Roskilde in Denmark. The four turbines are placed on the arms protruding from a central pillar. The rotor diameter is 29 meters. The upper rotor pair hits a high of 74 meters above the ground, which means that this type of wind turbine can also be an option in places that do not allow wind turbines with a large rotor and a higher altitude.
One of the goals of the project, called Babylon, was to avoid the negative consequences of weight gain in larger rotors. A rule of thumb says that the effect increases with the square of the diameter of the rotor, while the weight increases with the cube of the diameter.
The multi-rotor facility at Risø will have a total installed capacity of 900 kW. Any commercial facilities can later be built for higher powers.