Session: 09-01-03 Installation, Marine Operations and Maintenance - 3

Paper Number: 80933

80933 - A Perspective of Decommissioning Methods for Bottom-Fixed Offshore Wind Turbines 

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 will become 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' foundations and transition pieces, on which significant duration of decommissioning operations is spent, is identified as a critical element, and will be focused on. The decommissioning challenges and the decommissioning techniques implemented in previous projects will be studied. These include partial removal of foundation using different methods like internal or external cutting and total removal of it. These techniques and methods will be investigated thoroughly, and new methodologies for cost-effective decommissioning will be proposed. Moreover, the environmental issues during the decommissioning process will be discussed.

Presenting Author: Soheil Salahshour University of Stavanger

Authors:

Soheil Salahshour University of Stavanger
Muk Chen Ong University of Stavanger
Bjørn Skaare University of Stavanger
Zhiyu Jiang University of Agder