Handbook of offshore wind farm decommissioning. Framework, technologies, logistics, processes, scenarios and sustainability

At the end of their operational life, offshore wind farms (OWF) have to be decommissioned. At present, there is little experience in decommissioning OWF. Due to the size and number of wind turbines, experiences can be transferred to the upcoming decommissioning of OWF only to a limited extent. The research project "SeeOff - Strategy development for efficient offshore wind farm decommissioning" has set itself the goal of supporting companies involved in OWF decommissioning in the development of sustainable OWF decommissioning strategies. We consider the decommissioning of OWF to be sustainable if it is cost-efficient, environmentally friendly as well as safe, fulfils all legal requirements and is publicly accepted. The research results are compiled in this "Handbook of offshore wind farm decommissioning". First, the requirements, especially of a legal, technical and organisational nature, for the decommissioning of OWF are presented (Chapter 2). For a reference OWF, decommissioning processes offshore and ashore, the associated technologies, logistics, procedures and resources are examined and described in detail (chapter 3). Based on this, ten decommissioning scenarios are developed and analysed in terms of their cost and resource efficiency, greenhouse gas emissions, occupational safety and impact on marine biodiversity. Within the framework of a multi-criteria decision analysis, a holistic evaluation of the decommissioning scenarios is carried out (Chapter 4). Finally, the research results, transferability of the decommissioning processes and the assessment approach and potential for improvement are discussed (Chapter 5).