Gravity based support structures for offshore wind turbine generators: Review of the installation process

• Identification of operating offshore wind farms with GBS support structures.
• Analysis of the different procedures used for the installation of GBS.
• Explanation of the main phases involved in the installation of GBS.
• Seabed preparation, manufacturing, transport and installation procedures.
• Ballasting and anti-scour protection procedures.

Support structures and foundations are key aspects for the future development of offshore wind facility projects. Their cost is approximately 35% of the total cost of this type of project. Different types of support structure have been considered in the offshore wind industry; the most common are steel monopiles, gravity based structures (GBS), jackets and tripods.GBS support structures have been selected as the most suitable in some operating offshore wind facilities, although to date their use has been limited. Some defend the advantages of the GBS concept in deeper locations. Nowadays, the importance of the GBS support structure is obvious.The main objective of this paper is to show the different phases involved in carrying out the installation of GBS for offshore wind facilities. For that purpose, it is necessary to identify the processes and methods employed in the offshore installation of the most relevant types of GBS in offshore wind facilities operating in Europe.