HSB and partners publish "Handbook of offshore wind farms decommissioning"

Wind power from offshore farms is one of the key technologies of the energy transition. In the future, the ambitious expansion of wind farms with ever higher and more effective turbines will be contrasted by resource-efficient decommissioning. The "Handbook of offshore wind farm decommissioning: framework, technologies, logistics, processes, scenarios and sustainability" published in June 2022 by Hochschule Bremen City University of Applied Sciences with joint partners outlines technical concepts for resource-efficient decommissioning and their impacts on the environment and costs. The project "SeeOff - Strategieentwicklung zum effizienten Rückbau von Offshore-Windparks" (development of efficient strategies for offshore wind farm decommissioning) (01.11.2018 - 30.04.2022), funded by the German Federal Ministry of Economics and Climate Protection, was dedicated to investigate possible decommissioning strategies and assess their sustainability. Under the leadership of Prof. Dr.-Ing. Silke Eckardt, Professor of Sustainable Energy Supply and Resource Efficiency, an interdisciplinary research team from the Schools of Architecture, Civil and Environmental Engineering and International Business at Hochschule Bremen City University of Applied Sciences, together with the joint partners Deutsche Windtechnik Repowering GmbH & Co. KG, Nehlsen GmbH & Co. KG and the German Offshore Wind Energy Foundation, as well as the associated partners Vattenfall Europe Windkraft GmbH, TenneT Offshore GmbH and EnBW Energie Baden-Württemberg AG investigated various aspects of sustainable decommissioning. At the end of the research project the handbook has now been published with many best-practice examples. ‘For me the 'Handbook of offshore wind farm decommissioning' represents the first public knowledge basis that provides a comprehensive understanding to a broad stakeholder forum interested in the decommissioning of offshore wind farms. The handbook will support the industry in developing sustainable decommissioning scenarios. And just in time as the wind industry also needs time to prepare for upcoming decommissioning projects’, Gencer Genc from Vattenfall Europe Windkraft GmbH explains the far-reaching significance of the project.

To date, only a few offshore wind farms have been decommissioned worldwide and they are not comparable to those installed in the German Exclusive Economic Zone in terms of location, power classes and size. The ‘Handbook of offshore wind farm decommissioning’ thus breaks new ground by outlining the legal framework and diverse technical requirements as well as decommissioning scenarios. In this context, dismantling techniques for, among others, the wind turbines and foundation structures, the inter-array cables and the offshore sub-station, but also the partial or complete decommissioning is evaluated with regard to impacts on marine biodiversity, economic efficiency, greenhouse gas emissions, occupational safety as well as the recovery rate of construction and demolition waste at sea and on land. ‘It has proven useful to approach the largely unknown field of decommissioning of offshore wind farms by investigating and evaluating decommissioning processes. The information relevant for the calculation of decision criteria (e.g. costs, process durations or fuel consumption) was collected in a large data set. By this manner, a comprehensive knowledge and data base was built up, by which potential improvements for a more sustainable decommissioning of offshore wind farms could be identified’, says Prof. Dr.-Ing. Silke Eckardt, summing up the research project, which, with many transferable results, has met with great regional and international interest in research and business.