Moment of truth nears for would-be floating wind disruptors

Two floating wind pilots packed with the kind of innovations that could boost competitiveness across the sector are nearing showtime in locations off Portugal and Spain although, in one case, permitting delays are still causing concern.

The projects in question stand out for the disruptive nature of designs that attempt to address key issues that have been holding back floating wind from scaling up profitably.

Reducing the levelised cost of energy (LCOE) has become critical as rising supply chain and capital costs, exacerbated by vessel and port bottlenecks, have prevented the sector from making up any ground on the much more mature, and profitable, bottom-fixed sector.

While initial strides in deploying pre-commercial production have mainly featured semi-submersible hulls and versions of catenary or taut mooring systems, attention is increasingly focusing on designs that allow for lighter steel structures while facilitating industrialised mass production with lower-cost installation and logistics.

In Spain, floating innovator, X1 Wind, is chomping at the bit to start developing an 8.5MW of a new floating wind technology that has already been tested as a prototype in the Canary Islands.

The design has a weathervaning downwind configuration that allows the floating turbine to align passively with the wind, continually optimising its position and allowing for longer, lighter blades.

The project mounts a shallow-draft semisubmersible hull on a tension leg platform (TLP) with single point mooring.

“One of the things we want to prove to developers is the potential of a design like ours to reduce the amount of steel that is required quite dramatically,” said Alex Raventos, CEO and co-founder of X1 Wind.

He describes as a weight ratio under 170 tonnes per megawatt as “roughly half that of other pre-commercial projects on a similar scale so far in Europe.”

In what it describes as a “final step” toward commercialisation, the NextFloat pilot is expected to operate at the future Plemcat marine energy test site off northeastern Spain for at least five years, although certification is for 25 years.

Plug and play?

X1 reckons its patented connection and disconnection system could be a game changer for a sector where installation costs and maintenance scenarios have become a sticking point with banks and insurers.

Pre-installation of the mooring system and platform, with dynamic cables attached, means the floating substructure and turbine can then be towed in and positioned on top, using a ballasting and connection procedure and without the need for large construction vessels.

This whole process can be carried out by workhorse tugs and multi-cat vessels rather than the multiple anchor handling vessels required when it comes to pre-tensioning catenary mooring lines or traditional TLPs, says Raventos.

“Our alternative is very important for reducing installation costs but even more important for O&M,” says Raventos, who thinks the sector may have been optimistic about reliability as offshore wind began its expansion into the motions of deeper waters.

“Clearly failures are going to occur in this kind of marine environment, so having the ability to do corrective maintenance quicky and easily is going to be a key factor, and this is one of the key aspects that are that we want to test within the project.”

Permitting pinch

NextFloat has secured 80% of its capex financing, including two EU innovation grants and another from the French government, but financial closure depends on the conclusion of permitting procedures.

The project was originally going to be located in France’s Mistral test site, with installation in the Gulf of Lion targeted for 2025 but permits for this location were not renewed

The project was then moved to Spain where the Catalan autonomous regional government has given its backing to a new test site for marine energies.

The Plemcat facility, to be located in the Gulf of Roses, will feature a floating hub providing connection points to three pilot projects, of which NextFloat is one.

The Catalonia Institute for Energy Research (IREC) initially aimed to have the facility ready in the first quarter of 2026 but the permits to start construction have not been obtained yet.

"We remain confident that these permits will come in 2025 and, if so, we expect construction of the Plemcat site to be concluded by 2027," says Raventos.

Time to design

Raventos says the NextFloat consortium has also used the time to continue optimising design and reducing capex. Changes have included new connector designs, new materials for mooring lines and a mechanism for adjusting the length of mooring lines using of a diverless ROV.

“Incorporating two lines per mooring point builds redundancies into our system but it is critical to ensure that these lines are exactly the same length,” Raventos explains.

The NextFloat consortium has also been engaging with scores of European fabricators and suppliers, especially in Spain.

Raventos points out that lighter structural designs, with smaller diameters, and construction in blocks help avoid supply chain bottlenecks by opening the game to more players.

The company has identified more than 20 potential fabricators of structural components, and is looking to harness one of the most competitive and automated corners of the European onshore wind supply chain, namely onshore towers.

"We are talking with onshore tower manufacturers to supply what we call the masts. We've been able to improve the design of these columns so they can be mass-produced," Raventos said.

Quayside assembly will take place at a site in Tarragona.

X1 Wind is also working on the engineering and certification of a scaled up version of the platform for 20MW turbines with diameters of up to 280 metres, but Raventos issues an alert on the permitting front.

"The situation right now is not the easiest in the sector and these delays are impacting us. We're confident that the project has a lot of interest.

"If you don't have this data, then you cannot really understand what the impacts of these technologies will be. Pilots need to move into the water fast, otherwise Europe will not be able to compete." he says.

"Hopefully the permit will come in the second quarter, but we need it in place this year for sure so that we can start construction, which will take around one year and a half. Otherwise, we may lose all the financing that we have.. we cannot postpone this forever."

In Raventos' view, the whole floating offshore wind sector is now facing up to the fact that traditional concepts will not be enough to get LCOE down to levels that are comparable with bottom fixed wind.

"There's a need of disruptive concepts that are specifically adapted for floating conditions," he says.

"There was some aversion to these concepts, but I think that the picture has changed dramatically, and many companies are changing their designs.

"More than ever, pilots are key for Europe right now to succeed and to show that some of the big challenges that floating wind sector is facing can be overcome with innovation."

Gazelle takes a leap.

In Portugal, Gazelle Wind Power has already received its approvals to deploy a 2MW demonstrator that will set out to prove the company's claim to be able to reduce the LCOE for floating wind by 30% and broaden options for integration sites, "helping make floating wind commercially viable".

Gazelle Wind Power’s naval architecture draws on established offshore technologies, with elements of semi-submersible, spar and barge.

A dynamic mooring system results in a configuration that is analogous to a tension leg platform. Six mooring lines connecting vertically to the hull's outer column arms, sharing three mooring foundations in pair to create a geometry that helps the platform move horizontally and vertically to minimise tilting.

A counterweight suspended below the centre of the hull makes the platform behave more like a spar than a semi-submersible structure in the water. Once connected, the counterweight spreads the load dynamically, reducing mooring tensions.

When the counterweight is retracted, the hull's draft is a fraction of that of conventional spar, meaning developers can include shallow water ports among their options for integration and maintenance sites.

Gazelle says its design also facilitates quicker mooring connections without the need for large vessels or sea cranes.

For example, pre-tensioning of the mooring lines occurs automatically on connection by deploying the counterweight mass on the lines, reducing dependance on such assets and speeding up the maritime operation.

Electrical power cables can be connected and disconnected on the topside without the use of wet mate connections.

Mass produced floating wind?

Gazelle has also been working on a scaled up version of the demonstrator, to host 15MW turbines in the future.

Salazar says the chief goal of the pilot project is to demonstrate the principles and performance of the technology, but it will also initiate a procurement strategy that prizes local supply chains.

“Globalisation has been on the retreat for years now and now we are seeing an acceleration of a trend towards regionalisation,” Salazar reflects.

“Local content requirements can bring their own issues, such as skills shortages, but Portugal and Spain are well positioned. We are partnering with leading industrial groups in Portugal, and we have an excellent partner in DST.”

Gazelle was also an early mover in adapting the technology to broaden the fabrication scope to include flat-line panelling and modular assembly.

"Iberia has a long shipbuilding history and has many shipyards and steel manufacturers that are used to using flat panel lines.... Spanish and Portuguese companies are also doing very well when it comes to innovation, " Salazar says.

“Our goal is to become the second technology ever tested in the Atlantic Ocean, but the first one that can be mass-produced using a regional or national or Iberian supply chain.”

“This is a region that has a lot of tradition in shipping and can be the heart and lungs of a future floating offshore wind industry," Salazar enthuses.

Salazar is satisfied with how the permitting process has unfolded in Portugal, despite the backdrop of three general elections in less than four years.

He admits that the political instability has a “ripple effect” in the relevant ministries but says this has not interfered in the process of assembling a supply chain and feeding data back to the company's technical teams.

"Several different ministries were involved in all these processes, and I think Portugal has shown that the political will is there, even if there is uncertainty and political change. Despite all the uncertainty, we've been able to get the authorisation."

The Agucadoura project site, previously hosted WindFloat 1, one of Europe’s earliest floating wind pilot projects and, despite opposition from fishing groups in the northern region of Portugal, this area already has an industry footprint.

"I think our early engagement with the fisheries and the local authorities was important," Salazar says. "Portugal has shown that it has the will to take floating offshore wind forward."