Currently most of the licences for offshore wind farm development zones are granted with a lease period of 20 to 25 years. As a consequence the turbines have to be built to last for at least that period. There are several elements that can affect the life span of a turbine once it is installed and in operation. They need, for example, to be strong enough to endure the movement stresses that take place on an operational turbine. However, the biggest challenge comes from nature itself.

The harsh winds offshore, while needed to get the best energy output, are at the same time a turbine’s enemy due to their corrosive nature. UV also plays a role but the biggest enemy is the sea, with its salt content, which damages the steel foundations. The splash zone is especially vulnerable as it is here where air, water, salt and UV are all attacking the steel components and the protective coating at the same time with aggressive and varying types of corrosion.