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. 

A monopile cover is a necessary stopgap in the stage between the foundations and the tower of a wind turbine being installed. It offers protection against seawater, rain and bird droppings. “Our people must be able to work safely around the foundations, while the cabling is being retracted, for example,” says Olaf Rick, Civil Works Package Manager at Vattenfall, who was involved in designing the sustainable monopile covers. In the past, covers used to be made of tent tarpaulin or aluminium. However, the tarpaulin was susceptible to wind and mildew and did not allow daylight through, while the aluminium tended to be scrapped after a single use.