German energy giant RWE’s renewables arm is partnering with Spanish floating wind outfit Saitec to test a full-scale model of its innovative SATH (Swing Around Twin Hull) concept at a deep water site off northern Spain, starting next year.

As part of the so-called DemoSATH project, set to run to 2024 including a two-year operations phase, the two companies will trial a 2MW version of the design, which is built around conjoined cylindrical pre-stressed concrete hulls anchored to the seabed via a single-point mooring system, in 85 metres of water at the Biscay Marine Energy Platform (BiMEP).

The focus of the pilot is on the “performance and on the load behaviour of the platform under operational and extreme conditions”, as well as building on operational experience, including vessel-to-platform access and replacement of large components.

“We see great potential for floating wind farms worldwide,” said RWE Renewables CEO Anja-Isabel Dotzenrath. “Especially in countries with deeper coastal waters, this opens up attractive opportunities. With DemoSATH, we are gaining experience with an innovative concrete-based platform technology that will help us to position ourselves in this growth market.”

Saitec Offshore COO Luis González-Pinto stated: “The potential of SATH to reduce the cost of floating wind is immense. Now is the time to build and operate this floating wind turbine and widen this exciting market.

“This is an agreement between a well-established player in offshore wind, and a young innovative company. We are confident that this combination can provide massive gains for both parties.”

Saitec is in the final throes of building a 1:6 version of its 2MW design, for installation this spring in the Cantabrian Sea off Santander, Spain for a 12-month testing programme.

“BlueSATH will be sailed in April when an adequate weather window arise,” González-Pinto told Recharge. “It is true that the timelines of both projects are close, but all steps from manufacturing to operation of BlueSATH provide hints of improvements or minor things to correct.”

The company’s longer-term aim is to scale-up the SATH concept to 10-15MW, an ambition that could be accelerated with the backing of an international developer such as RWE.

“Obviously we must get DemoSATH right and operate it. Nevertheless, given the time-scale of offshore wind projects we are already working on, projects using turbines on the 10-15MW range are under consideration.”

González-Pinto noted that while he “could not disclose any information of several projects we are working on”, he expects that “by 2024 there will be at least one wind farm using several SATHs”, adding that Saitec is currently in home-stretch discussions with a preferred turbine supplier “for a long time in close collaboration”.

“Now the last terms are under negotiation, so we will very probably announce it before the summer,” González-Pinto added.

Though Europe, with over half of the total floating wind capacity installed and expectations for some 320MW off its coasts by 2021, is the current market pace-setter, Asian plays in Japan and Korea, as well as the US Pacific, have recently heaved into view with international-scale ambitions, with California most recently seeing set-up of a coalition that is calling on the state government to support construction of 10GW of floating wind by 2045.

Norwegian energy giant Equinor set out a road map in 2017 when it brought online the world's first floating wind array, Hywind Scotland, which forecast 12-15GW of moored units turning by 2030 at a levellised cost of energy of €40-60/MWh, the current price of conventional offshore wind power.