Floating Offshore Wind Platform StormCatch: Extending Wind Farms 100 Kilometers Out to Sea

StormCatch, the floating offshore wind platform jointly developed by Norway's energy major Equinor and France's TotalEnergies, completed its first offshore test in Stavanger, Norway. The technology allows wind farms to be deployed in waters more than 500 meters deep, well beyond the 60-meter depth limit of conventional fixed-bottom wind.

Traditional offshore wind uses monopile or jacket foundations that fix the turbine tower to the seabed. That structure works in shallow waters up to 60 meters deep, but more than 80 percent of the world's potential offshore wind resource sits in waters deeper than that. StormCatch addresses that limit with a floating foundation.

StormCatch uses a semi-submersible floating foundation made of three cylindrical floats arranged in a triangle. The foundation is moored to the seabed by nine anchor chains using a tension leg design that keeps the platform stable under wind and waves. The foundation is rated for 17-meter waves and gusts of up to 32 meters per second.

On the turbine side, StormCatch is equipped with GE Renewable Energy's latest Haliade-X 15 MW offshore wind turbine. The turbine's rotor has a 236-meter diameter, with a swept area equivalent to four standard football fields. Each turbine can generate about 67 million kWh per year, enough to power 24,000 UK households.

The first 12 StormCatch turbines will be installed about 120 kilometers off the coast of Aberdeenshire, Scotland, in waters roughly 480 meters deep. The full wind farm, named Pentland Floating Wind, is expected to generate about 800 million kWh per year. The project has a total investment of 2.1 billion pounds and is supported by the UK's Contracts for Difference mechanism.

Mads Holm, head of renewables at Equinor, said StormCatch validates the commercial viability of deep-water offshore wind. The levelized cost of electricity from floating wind is still higher than fixed-bottom wind, but with scale-up and supply chain maturation, it is expected to reach parity by around 2030.

On the technical challenge side, the biggest issue for floating wind is the short offshore work window. Strong winds and waves in deep water make installation difficult and risky. StormCatch uses a modular design where all critical components are pre-assembled onshore, reducing offshore work time to about five days per turbine.

On the environmental side, floating wind has less impact on the seabed than fixed-bottom wind. The anchor chain system leaves only nine small contact points on the seabed, far fewer than the disturbance caused by traditional monopile installation. Deep-water areas also have lower biodiversity than nearshore waters, so the wind farm's impact on fisheries is smaller.

The floating wind supply chain is taking shape. Norway, South Korea, and Spain have set up specialized floating foundation manufacturing facilities, each able to produce more than 50 floating foundation units per year. The International Energy Agency forecasts global floating wind installed capacity could reach 60 GW by 2030.