Evaluating environmental impacts and public preferences in offshore wind farm decommissioning

The expansion of offshore wind energy presents new challenges as many wind farms approach the end of their operational lives and will need to be decommissioned. This study presents the first multi-criteria assessment of offshore wind farm decommissioning scenarios that brings together life cycle environmental impacts, local marine benthic biodiversity impacts, and public preferences. Using Horns Rev 1 – the oldest large-scale wind farm in the North Sea - as a case study, we analyze 16 decommissioning scenarios ranging from full removal of infrastructure to partial removal strategies in which parts of the foundation, scour protection, or cables are left in place. Environmental impacts are assessed through life cycle assessment, and local marine biodiversity impacts are quantified using a newly developed method tailored to North Sea habitats. Public preferences are analyzed based on a nationally representative Danish survey. Our findings show that removing high-value recyclable materials while leaving scour protection in place yields the lowest life cycle environmental impacts due to recycling benefits and avoided removal of components with low recycling value. In contrast, full removal receives the strongest public support and best aligns with restoration of the sandy seabed but also results in higher climate impacts. Biodiversity outcomes depend on the selected reference state and desired ecological function, with trade-offs between supporting native benthic communities and preserving artificial reef structures that support diverse communities. This study demonstrates the value of a multi-criteria approach to offshore wind decommissioning and provides a transferable framework supporting decision-making by integrating environmental, ecological, and societal dimensions. • First integrated LCA, biodiversity, and social acceptance study of decommissioning. • Sixteen decommissioning scenarios assessed for Horns Rev. 1 wind farm. • Findings support flexible, site-specific, and participatory decommissioning policy. • Partial removal can reduce climate impacts while preserving artificial reef habitat. • Public preferences favor full removal.