Enersea, engineering party in sustainable monopile cover for Vattenfall

Up to now most monopile covers, which protect the airtight platform inside the monopile, have been made of aluminum or steel. None of these covers have been reused for new offshore wind farms and recycling steel and aluminum specifically is an energy consuming process. A third variant is a tent cover which also has disadvantages. At high wind speeds there is a risk that they are blown away, contaminate the sea and leave the monopile unprotected.

Wind farm developer Vattenfall asked Sif, which has been granted the assignment to build the monopiles, to come up with a smart and environmentally friendly solution for the monopile covers. Quickly the ball started rolling and Enersea, Theuws and Kansen Voor West got involved and joined forces. Together a first concept was developed which resembles an ingenious birthday cake.

A new and sustainable concept

The construction consists of different fiber reinforced polyester panels and looks a little bit like pieces in a pie. ‘It was not the first material we thought of’, Christian Larsen, project engineer for Vattenfall at HKZ, admits. ‘But we wanted a new and sustainable concept and gave our subcontractors the freedom to come up with a new concept, both in terms of construction as well as in material choice.’

The idea behind the different panels is that you can reuse the top panels of the cover for every diameter of offshore monopile which is currently on the market. Top diameters of monopiles typically vary between 6 and 8m and the concept perfectly matches for those diameters. The MP covers can be tailor made by using longer or shorter parts on the slope in order to adjust to the exact diameter of the monopile in a new project.

In Ocean Energy Resources magazine an article was published about this innovation. Click here for the full story, pages 4-8.