Abstract
The number of decommissioning activities in the offshore wind industry will increase in the coming years as many wind turbines reach their planned service lifetimes. Cost-effective solutions for decommissioning are important considering the levelized cost of energy of offshore wind farms. In addition to the existing challenges in marine operations such as waiting for suitable weather window, logistics and availability of the vessels, the limited experience in offshore wind decommissioning makes the process more challenging regarding the fact that the size of current installations of offshore wind turbines is growing considerably and more preparation and competence are required in association with new projects. In this paper, a review of existing decommissioning methods for offshore bottom-fixed wind turbines is provided first. The removal of wind turbines’ foundation and transition piece, on which significant duration of decommissioning operation is spent, is identified as a critical element, and is focused on. The decommissioning challenges and the decommissioning techniques implemented in previous projects are studied. These include partial and complete removals of foundations. These techniques and methods will be investigated thoroughly.
