As offshore wind projects expand globally, the need for robust infrastructure to transmit generated power to the grid is growing, particularly in Europe. Research by Rystad Energy indicates that 137 offshore substations will be installed in continental Europe by 2030, with an estimated investment of $20 billion. More than 120 of these will be built between 2024 and 2030, requiring about $18 billion. Consequently, spending on offshore substations is projected to rise significantly, increasing from an average of $1.4 billion per year from 2015 to 2023 to $8.4 billion by 2030.

Offshore substations play a pivotal role in the offshore wind sector, gathering power from wind turbines, boosting the voltage, and transmitting it to the shore. The main components of these substations include switchgears, transformers/converters, a reactive power compensation system, and an earthing system. These substations are essential for projects with capacities exceeding 200 megawatts (MW) and located over 15 kilometers from the shore, helping to reduce power transmission losses. They also support other energy projects, such as electrifying offshore oil and gas platforms.

European targets for offshore wind capacity

The drive for more substations is driven by the growing scale of offshore wind farms and their distance from shore. Projects with capacities over 1 gigawatt (GW) typically require multiple substations. European countries have set ambitious targets for offshore wind capacity, aiming to establish the continent as a substation hub. In 2024, eight new offshore substations are expected to be installed, doubling last year’s count. Initially, these substations will be part of wind projects within 50 kilometers of the coast. However, an increase in installations beyond the 50-km mark is anticipated in the latter half of the decade, boosting the demand for offshore substations.

According to Petra Manuel, Senior Offshore Wind Analyst at Rystad Energy, spending on offshore substations will see a significant rise this decade, driven by the growing installed capacity in Europe and the expected adoption of floating wind technology. Floating turbines, positioned far from shore, could lead to the development of the first floating substations in the early 2030s.

Composition of offshore substations

Offshore substations are typically composed of two main parts: the topside, housing the main electrical system, auxiliary systems, and the topside housing, and the foundation, which supports the topside structure. Jackets, fixed to the seabed with piles at each leg, have been the predominant foundation type for offshore substations due to their ability to support larger structures. However, some projects have utilized monopiles driven directly into the seabed.

The topside of an offshore substation is significantly large and heavy, often exceeding the weight of a wind turbine. Between 2014 and 2016, nearly 100 offshore substations were installed in Europe, with jackets making up almost 70% of the total, while monopiles accounted for less than a quarter. The foundation types for substations planned for 2025 and 2026 are not yet finalized, and some are listed as unspecified in the research.