Demonstrating floating offshore wind technology in Norway

Location

Goliat, located in the Barents Sea, 85km northwest of Hammerfest, Norway, is the largest cylindrical floating production storage and offloading unit for oil production in the world. It is currently powered from shore via a 75 MW power cable.

The purpose of the GoliatVIND project is to demonstrate floating offshore wind technology in Norway by using floating wind turbines to supply the platform with clean renewable energy. The area has a water depth of 300 to 400 meters and is an ideal location to demonstrate the versatility of floating offshore wind.

The facility

The plant is planned with 5 wind turbines. Each turbine will have a capacity of 15 MW, with a planned total capacity for the project of 75MW. The floating foundation used for the GoliatVIND project is Odfjell Oceanwind's Deepsea Star™, a semi-submersible foundation with a turbine located in the centre. The foundation is made of steel. The floater is designed as a triangle with a length of approximately 100 meters on each side. Each corner consists of buoyancy columns that include ballast. The turbine tower has a height of 135-170 m, while the rotor diameter (length from blade tip to blade tip) is between 220 and 260 metres.

Each foundation has six anchors, each with an anchor line with a horizontal length of 1,700 meters. This distance between turbine and anchor can be changed based on optimization of the anchoring solution. Six anchors per turbine have been chosen as a safety measure related to proximity to existing oil and gas infrastructure.

Two types of anchors are considered: suction anchors or drag anchors. For each floating unit, a location-specific analysis must be carried out to determine the type and size of anchor.

An internal cable is planned from each turbine to a common substation. It has not been decided whether this will be placed on the seabed or on one of the units. An export cable to the Goliat platform is planned from the substation.