The role of offshore substations in wind energy

Offshore substations (OSS) are hubs for the collection, transformation and transmission of electricity produced by offshore wind turbines. These structures convert electricity to higher voltages suitable for long-distance transmission to onshore substations, minimising power loss along the way.

OSS are either fixed to the seabed using foundations such as monopiles or jackets, or arefloating offshore substations, which are anchored and buoyed. Floating designs are increasingly popular for deeper waters, offering scalability and adaptability to new wind farm sites.

Offshore substations vary in size but are typically comprised of four key levels:

This deck facilitates the pull-in installation of export cables that connect the offshore substation to onshore facilities.

This floor houses high and medium-voltage equipment, including the critical power transformer.

This level includes rooms for day crews and additional support equipment.

The top deck accommodates the main crane used for lifting heavy equipment during construction and maintenance operations.

In essence, the role of offshore wind substations is to facilitate efficient energy transport, reduce transmission losses and enhance grid stability. These structures include advanced monitoring and control systems to ensure optimal operation of wind farms. For example, in large-scale OSS wind farm projects like those in the North Sea, substations are critical to meeting grid compliance and maintaining energy reliability.

Building an OSS platform involves advanced engineering to ensure stability and durability in harsh marine environments.

Key stages of construction include:

Substations are custom designed based on wind farm size and location. They integrate dynamic cables and electrical equipment made to withstand a corrosive marine environment and harsh weather conditions.

Large cranes and specialised vessels are used to transport and install substations.

Once installed, substations undergo rigorous testing to ensure they meet operational and safety standards.

A key advantage of floating offshore substations is that they eliminate the need for seabed foundations, reducing both installation costs and environmental impact. Efforts are underway to refine the design and operation of floating OSS, ensuring reliability in unstable marine conditions. Such innovations are playing an important role in the transition to renewable energy sources.