Ferrovial will manufacture and assemble the DemoSath floating platform to be deployed off the Basque coast in northern Spain. Image courtesy of RWE Renewables.
The DemoSath wind power pilot project consists of a 2MW wind turbine anchored through hybrid mooring lines to the seabed. Image courtesy of Saitec Offshore Technologies.
The DemoSath wind power pilot project is being developed through the collaboration between Saitec Offshore Technologies and RWE Renewables. Image courtesy of Saitec Offshore Technologies.

DemoSath is a floating offshore wind power pilot project being developed off the Basque coast of Armintza in northern Spain.

Spanish engineering firm Saitec Offshore Technologies is executing the £13.12m ($16.95m) demonstration project in partnership with German-based RWE Renewables. It will be the first multi-megawatt floating wind turbine to be deployed in Spain.

The pilot project is intended to test the offshore behavior of the floating wind turbine platform connected to the Spanish grid under real operational and extreme situations.

The partners also aim to collect data and secure practical knowledge to test the construction procedure for mass electricity production through floating wind turbines.

The turbine manufacturing and assembly contract was awarded in October 2020, while the construction work on the project is expected to begin by the end of 2020 and continue for 14 months, creating up to 60 jobs for locals during the peak construction period.

Scheduled to commence operations for up to two years from early 2022 onwards, the DemoSath floating power project is expected to generate enough electricity to power approximately 2,000 households while eliminating approximately 5,100 tonnes (t) of CO2 a year.

Location and site details

The DemoSath offshore floating wind power project is located off the coast of Armintza in the Port of Bilbao, in northern Spain. The floating platform structure and the wind turbine assembling site will be in the Port of Bilbao.

The wind turbine will be installed in the open sea test area Biscay Marine Energy Platform (BiMEP) situated approximately 2km off the coast of Armintza at a depth of 85m.

DemoSath pilot project make-up

The DemoSath floating offshore wind power project will utilise SATH (swinging around twin hull) prestressed concrete floating platform comprising cylindrical and horizontal hulls. The floater will align itself on a single mooring point according to the wind direction.

The prototype involves a 2MW wind turbine with a rotor diameter of 96m, while the base of the floating platform structure will be 64m-long and 30m-wide.

The floating platform will be towed to an anchorage point in the BiMEP test field and anchored to the seabed through hybrid mooring lines made of chains and fibre.

DemoSath is Saitec Offshore’s second floating offshore wind turbine deployment project after the BlueSath, which consists of a 1:6 scale prototype of a 10MW wind turbine. The 30kW turbine, which was installed off the coast of Santander in August 2020, measures 17m in height and 50t in weight and has a rotor diameter of 15m.

The test conclusions of the BlueSath project will be applied to the DemoSath pilot project.

DemoSath wind pilot project power transmission

The electricity generated by the DemoSath pilot project during testing will be fed to the Spanish grid through underwater electrical cables from the BiMEP site.

Project financing

The floating offshore wind power project has secured finance of £10.50m ($13.56m) through grants, equity investment, as well as research and development tax credit transfer.

A part of the project costs will also be financed by RWE Renewables.

Partners involved

Saitec Offshore and RWE Renewables entered into a collaboration agreement for the DemoSath floating wind power pilot project in February 2020.

Saitec Offshore is responsible for the design, project management, operation, maintenance, and data treatment services, while its partner RWE Renewables will contribute offshore expertise along with part-financing.

Saitec Offshore Technologies and BiMEP signed a contract for the installation of the BiMEP test platform at the DemoSath project in June 2020. BiMEP is owned by Ente Vasco de la Energía-EVE (75%) and the Institute for Energy Diversification and Saving (IDEA) of the Ministry for the Ecological Transition and Demographic Challenge (25%).

Contracts awarded

Ferrovial was contracted for the manufacturing and assembly of the SATH floating platform in October 2020. The scope of the contract also includes site preparation works, precast components production, and steel supply.

Worley was previously engaged for advisory services related to accessibility design assessment of the DemoSath floating wind turbine power project.