Scottish offshore energy company Equinor has revealed its preferred floating wind foundation design for full-scale gigawatt (GW) commercial floating offshore wind, if successful in the ScotWind leasing round.

The Wind Semi, a semi-submersible wind turbine foundation, has been designed with flexibility, specifically to allow for fabrication and assembly based on local supply chain capabilities.

According to Equinor, the new floating wind concept will enable industrial standardization and maximize opportunities for local supply chains.

Read more: A supply chain is born: Can the U.S. reach 30 GW of offshore wind by 2030?

“We are ready to develop the next generation, large-scale commercial floating offshore wind in Scotland…we plan to develop GW-size floating projects in one single phase.

Sonja C. Indrebø, Equinor’s vice president of Floating Offshore Wind. Credit: Equinor

“Implementing large-scale projects will accelerate Scotland’s energy transition to net zero. At 1GW, this project would be over 30 times bigger than Hywind Scotland, the UK’s and Equinor’s first floating project and have the potential to not only position Scotland as a leader in deepwater technology but also create opportunities for both existing suppliers and new entrants to the offshore wind sector,” says Sonja C. Indrebø, Equinor’s vice president of Floating Offshore Wind.

To ensure the technology is cost-effective, Equinor has developed a set of design principles and solutions that are applicable across floating concepts.

Equinor operates Hywind Scotland (30 MW) floating wind farm and believes this project demonstrates the true potential of floating offshore wind.

“Hywind Scotland proved that the floating concept works, and as we move to the next generation floating offshore wind projects, we need to demonstrate that floating offshore wind is deployable at scale, in different geographies cost-effectively whilst bringing local benefits. We have seen the journey of fixed bottom offshore wind, and combined with our long experience in floating, we can take learnings into account as we design and innovate the concepts for full-scale GW floating wind farms”, says Indrebø.

Image credit: Equinor

The Wind Semi has several features making it particularly suited for harsh waters:

Dependability: By introducing a passive ballast system, the Wind Semi has a simple substructure design, reducing the risk of system failure and the amount of maintenance needed

Simple, robust design: A flat plate design that is free from bracings, heave plates, and complicated nodes that are prone to fatigue cracking

Flexibility towards the supply chain: With a harbor draught of less than 10 m, the Wind Semi’s turbine integration can be assembled at most industrialized ports. The Wind Semi’s simpler flat plate design enables the substructure to be built in blocks that can either be fabricated locally and/or shipped from other locations.

“With a design-based approach we’ve used our experience and gone right back to basics to incorporate this focus in the initial concept design,” says Indrebø.