Life cycle assessment of floating offshore wind anchors: A state-of-the-art review

Floating offshore wind (FOW) is moving from demonstration projects towards commercial-scale deployment, but the lifecycle greenhouse-gas implications of its anchoring systems remain poorly resolved. This paper presents a state-of-the-art review of how FOW anchors are represented in life cycle assessment (LCA) studies, focusing on system boundaries, functional units, lifecycle-stage coverage, anchor disaggregation, and the links between environmental impacts and engineering function. The review shows that anchor-related emissions are controlled by coupled drivers: material demand, fabrication route, installation-vessel logistics, mooring configuration, load direction, soil conditions, and end-of-life treatment. These drivers are often hidden in current LCAs because anchors are aggregated with mooring lines, foundations, substructures, or farm-level inventories and are commonly normalised by electricity production. To address this mismatch, the paper proposes a complementary component-level functional unit, the provision of 1 MN of holding capacity under stated reference conditions, and an associated capacity-normalised carbon-intensity indicator expressed in tCO 2 eq/MN. The indicator is meaningful only when reference conditions are stated, including soil class, load inclination, static or cyclic capacity basis, capacity definition, and lifecycle boundary. Applied to the four studies in the review that report both anchor-level emissions and holding capacity, the indicator can preserve material- and installation-related trends. This quantitative base is, however, too narrow to rank anchor technologies, and the demonstration is presented as a proof of concept rather than as a benchmarking result. The paper concludes with a practical reporting framework intended to support transparent anchor-level benchmarking and low-carbon anchor selection in future FOW projects.