linguistic:voice_change, structural:summarization
Maintenance

Wind turbines need regular maintenance to stay reliable and available. In the best case turbines are available to generate energy 98% of the time. Ice accretion on turbine blades has also been found to greatly reduce the efficiency of wind turbines, which is a common challenge in cold climates where in-cloud icing and freezing rain events occur. Deicing is mainly performed by internal heating or in some cases, by helicopters spraying clean warm water on the blades.

Modern turbines usually have a small onboard crane for hoisting maintenance tools and minor components. However, large, heavy components like generators, gearboxes, blades, and so on are rarely replaced, and a heavy lift external crane is needed in those cases. If the turbine has a difficult access road, a containerized crane can be lifted up by the internal crane to provide heavier lifting.