In the past few years, we have covered a bunch of fascinating drones from Aerones. As it happens, they build drones capable of cleaning and de-icing wind turbines. They are powered from ground level to work for hours and have redundancy.
These drones allow cleaning of the blades without putting humans in danger. They can move around the blade or in snake fashion. The water shooting nozzle can target specific spots. The pressure is adjustable.