The blades of wind turbines must be ice-free in order to function properly. Scientists have developed an inexpensive method of using drones to apply an environmentally friendly de-icing coating to the blades.

If too much ice accumulates on the blades, they rotate more slowly, producing less energy. Moreover, if there is a different level of icing on all three blades, the balance of the turbine may be disrupted, which will lead to increased wear and possibly even breakage.

There are de-icing systems that can be integrated into the blades, but they may not be affordable for many wind farm operators. The same can be said about using helicopters to apply chemicals to prevent icing.

In search of a more economical, but at the same time effective alternative, scientists from two departments of the German Fraunhofer research group recently turned to unmanned aerial vehicles. The research project was named "TURBO – Temporary coating by means of drones".

In the current version, the system is a hexacopter equipped with a small pump that pumps a liquid mixture of urea and wax under high pressure into a long thin spear, at the end of which there is a nozzle with a diameter of only 0.3 millimeters. The system sprays the mixture under high pressure, forming droplets with a diameter of 100 microns.

With this installation, the drone successfully applied coatings of sprayed droplets to the icy edges of wind turbine blades at wind speeds up to 35 km/h. After solidification, this protective coating prevents the formation of ice for several weeks, after which it is necessary to repeat the process.

Now scientists are looking for industrial partners to commercialize TURBO technology. Perhaps it will find application in the maintenance of power lines, the upper floors of tall buildings and other objects that are difficult to reach by conventional means.