Presentations

Abstract

Floating offshore wind enables the use of wind resources in water depths between 60 m and 2000 m, which represent over 75 % of global offshore potential. Due to limited shallow-water sites, this technology is essential to meet the 1.5 % climate target, requiring offshore capacity to increase from 68 GW in 2023 to 494 GW by 2030 and 2465 GW by 2050. As of 2025, floating wind remains in a pre-commercial stage, with Hywind Tampen (88 MW) being the largest project. A key technology gap is the grid integration of floating wind farms using substations. Current projects avoid offshore substations by using direct-to-shore connections, limiting scalability beyond 100 MW. This research evaluates bottom-fixed, floating, and subsea substations for varying site conditions to identify the most cost-efficient and technically viable solution for floating wind farms. A case study is performed for two wind farms (300 MW and 1.2 GW) at water depths of 100 m and 1000 m and distances of 10 km and 100 km from shore. A techno-economic framework is developed that combines recent industry reports with lifecycle cost modelling. The results show that for 1000 m water depth, subsea substations are the most cost-effective solution with and without maintenance. In scenarios with high energy prices and low discount rates, floating designs can outperform subsea alternatives due to lower maintenance and curtailment costs. At 100 m depth, bottom-fixed substations remain the preferred choice. The main advantage of switchgearless subsea substation over floating substations is the simplified architecture, absence of floaters and mooring systems, ease of installation and cable layout optimization, which comes with a trade-off regarding fault isolation, grid code compliance, and complex subsea environment in case of a failure.