Floating wind is an emerging sector with only a few turbines installed to date in contrast to the maturing bottom-fixed wind market. There are some key differences between these new floating wind turbines and their more established bottom-fixed counterparts.
Bottom-fixed turbines are more suited to shallow waters while floating wind turbines can be deployed in waters over 60 metres. This increased water depth brings more complexities to the installation process mainly through costs associated with greater distances to shore. However, along with these challenges floating turbines have better access to consistent winds being further from shore and have less of an environmental impact on the seabed.
Early commercial floating wind projects have included between three and 11 floating units. Installation methods differ from bottom-fixed with more reliance on anchor handlers and construction support vessels rather than on heavy-lift assets. This aligns floating wind more with the practices used in oil and gas operations.
With offshore wind markets emerging from a troubled period, offshore wind could also begin a resurgence. If upcoming projects in France, the UK and South Korea reach their development milestones, then offshore floating wind could bring new opportunities for industry players, particularly in the OSV market.
Learning from past projects
With a handful of major projects now commissioned, some of which have already undergone some initial heavy maintenance, the sector can benefit from the lessons learned during each scope.
We have reviewed the maritime operations of four of these major floating wind projects: Provence Grand Large (France), Kincardine (UK), Hywind Tampen (Norway) and WindFloat Atlantic (UK). This review allowed us to establish a reference for estimating expected activities and marine spreads required during the construction of upcoming projects. This analysis focuses on three main phases which involve anchor handlers and tugs: anchor installation, towing to the offshore site, and hook-up.
Read More: Lessons learned from heavy maintenance at the world’s first commercial floating wind farm
Anchor Installation
- The anchor system installation is well established in offshore operations.
- Suction anchors reduce turbine spacing and optimize layout.
- Hywind Tampen used 1.8 anchors per turbine, fewer than the typical three, due to its optimized honeycomb pattern.
Towing Speed
- Spar foundations (Hywind Tampen) are harder to tow due to their deep draft, and their cylindrical shape requires additional stabilization.
- Towing speeds depend on weather conditions.
- Kincardine and Windfloat used one heavy AHTS, while PGL used three smaller tugs to improve maneuverability.
Hook-Up Duration
- Hook-up duration improved significantly due to the experimental nature of the projects, with on-the-job learning by the crew also contributing to performance gains.
- The marine spread includes two to four anchor-handling vessels and one construction vessel.
Carrying lessons forward: a Golfe du Lion case study
WindFloat Atlantic, Kincardine, and OceanWinds’ under-construction Golfe du Lion all utilize the same semisubmersible foundation design, allowing for a comparison of installation strategies and operational efficiency.
These past campaigns have shown that each turbine installation typically requires around five vessel days. With improved planning, forecasting, and crew experience, upcoming operations are expected to be quicker. Drawing from previous performance, a clear understanding of the necessary maritime operations is available.
At the time of writing, construction was well underway at Golfe du Lion floating wind project off the southern coast of France. The project follows the first floating wind farm offshore France, Provence Grand Large, and will be the next to achieve commissioning (which is expected later in 2025).
The anchors of the three turbines were pre-installed—a process which took one construction vessel with 250t bollard pull capacity 16.1 days excluding mob, demob and transit. Floaters are now being assembled with the first 10 MW turbine completed and ready for installation on June 10. The remaining units will follow in the coming months.
What does the future hold?
The floating wind market could really scale-up by 2030 with over 10 GW planned globally. Markets like South Korea and France see floating technology as particularly feasible and valuable for their renewable energy efforts.
By 2040, floating technology could take a much larger share of new capacity. Developers are increasingly counting on floating to become economically viable at scale. This is due to some clear advantages: access to deeper waters and proximity to existing offshore oil and gas infrastructure which alleviates the pressure on the heavy-lift fleet and offers fewer location constraints.
There are some key market milestones that will indicate that offshore floating wind is picking up:
- Final Investment Decision (FID) at the first South Korean floating wind projects are expected in 2025.
- The progression of Scotwind 1 and INTOG projects in the UK with first consent authorized and FID that could be reached by the end of 2025.
- Interest from developers for the first leasing rounds in Greece and the Canary Islands.
- Good uptake in the AO9 tender for France.
Yet, despite some optimism, the industry remains cautious for now. Floating demand remains uncertain as there are still several questions to address in order to bring floating projects to an industrial scale with sufficient profitability. For now there is a widespread “wait and see” approach because no large-scale commercial floating projects have yet fully demonstrated economic viability at scale.
Click here to find out more about our floating wind reports. With in-depth analysis of vessel performance and marine spread during the construction and heavy maintenance of the first four industrial-scale floating wind farms, these studies provide invaluable guidance for future planning. Or, find out more from our team by emailing directly: insights@spinergie.com.
.jpg)
