Before offshore wind turbines can be installed, their foundations need to be laid first. On top of each set of foundations stands a monopile with a cover, a temporary solution used to cap the huge tube. In the past, covers tended to be written off and destroyed after use. However, those used in the construction of the Hollandse Kust Zuid Offshore Wind Farm are durable, can be reused and will last as long as 10 to 15 years.