How classification helps de-risk and streamline floating platforms
Classification of floating platforms for offshore wind turbines can be a key element in a strategy to industrialize production of these technically complex structures. Odfjell Oceanwind therefore chose to collaborate with DNV to strengthen safety, reduce life-cycle risk, and develop a reliable basis for standardized production at scale.
DNV’s 2025 Energy Transition Outlook (ETO) sees global installed floating wind capacity reaching 330 GW by 2060. While the nearer-term expectations are more modest, the world’s growing energy hunger and a declining reliance on fossil fuels are driving the demand for renewables. Floating offshore wind, which benefits from the more constant and reliable wind conditions further away from shore in deepwater areas, will help accelerate and make the transition possible.
The role of classification in floating offshore wind
Like every emerging technology, floating offshore wind has to overcome hesitancy from parts of the industry, investors, insurers, and governments, not least because of cost- and feasibility-related, technical, and political concerns.
One key element in reassuring stakeholders that all possible steps have been taken to mitigate risks and avoid failures is a thorough project certification scheme, which includes classification. DNV firmly believes that a combined project certification and classification scheme which combines the optimal solution from the two worlds of power plants and maritime can play a prominent role in paving the way towards large-scale floating offshore wind plants by enabling safety and standardization through a consistent, life-cycle‑based rule framework.
Applying offshore drilling expertise to floating wind
Odfjell Oceanwind, headquartered in Bergen, Norway, was formed in 2020 when Odfjell Drilling invested in the Norwegian floating wind pioneer Oceanwind AS. Odfjell Oceanwind benefits from Odfjell Drilling’s 50 years of experience operating offshore drilling rigs in harsh environments, in particular a fleet of advanced semi-submersible rigs designed to operate efficiently in extreme conditions.
“There are many similarities between floating wind turbines and floating assets in oil and gas,” says Trond Grytten, EVP Design & Engineering at Odfjell Oceanwind. “They use the same structures, mooring, anchoring, equipment, and power cables, so we can operate in the same supply market.”
How classification led design helps de risk the Deepsea Star floater
Odfjell’s offshore experience contributed to the decision to design the Deepsea Star™, a semi-submersible floating platform for 14 MW and larger turbines, with classification in mind from the beginning. “Classification ensures adherence to established technical, safety, and environmental standards throughout the project life cycle, from the design stage to construction and operation,” says Grytten. “Choosing a quality class society lowers life-cycle risks and makes a big difference for the trust you get from investors and project stakeholders – bankers, insurance, investors, partners; even the supply chain can see that it’s a serious client.”
Classification of floating offshore wind turbine platforms is voluntary, says Johannes Emanuel Ottersen, Head of Section – Floating Offshore Wind at DNV. “DNV provides and recommends a combined, seamless scheme of project certification for the overall plant and classification for the floaters and mooring. For the floater itself and its mooring system we recommend classification because the yards are more accustomed to the class model, which provides a consistent set of rules for fabrication procedures, material specifications, documentation, and other aspects, all of which helps standardize production.”
Remote monitoring and risk-based inspection streamline class processes
There is a misconception about classification and class surveys, says Ottersen, that sometimes causes unwarranted scepticism: “It does not mean that you have to take the entire unit to the dock every five years,” he stresses. “Today’s class regimes work with remote monitoring and risk-based inspection schemes that help predict damage and schedule inspections accordingly.”
Grytten mentions another key aspect: “Classification helps de-risk any project at an early stage to avoid surprises later on. Then periodic in-service inspections and condition-based regimes keep the asset aligned with the rules during operation. Having chosen DNV as our classification society for the Deepsea Star™ shows project stakeholders that we can offer a well-thought-through life cycle.”
First projects hope to jump-start production at scale
Odfjell Oceanwind is currently involved in two projects that are considered stepping stones towards the industrialization of floating offshore wind:
- SCALEWIND, a demonstrator project planned at the METCentre about 10 km outside Karmøy, on the western Norwegian coast. It will comprise a single turbine of up to 24 MW, positioned in a water depth of roughly 200 metres.
- The Salamander wind farm project, located in north-eastern Scotland, is a test and demonstration project of 100 MW. If the partners decide in favour of 14 MW turbines, Odfjell Oceanwind will be able to furnish seven Deepsea Star™ units, says Grytten.
Both projects are government co-founded and expected to deliver valuable learnings. “Our philosophy at Odfjell is to move step by step, gather experience, and then advance with the larger utility-scale projects,” says Grytten.
Driving floating wind costs down through scale and standardization
Floating offshore wind can be considered technically mature; however, it is still considerably more costly than fixed offshore wind installations. Bringing the costs down is the core challenge. “Standardization, industrialized manufacture, and supply chain optimization are the means to achieve that,” says Grytten.
Another strategy to optimize the cost vs power ratio is to maximize the turbine rating. “The amount of steel required for the floater of a 20 MW turbine is not that much greater than for a smaller unit, but you capture a lot more power,” explains Ottersen. “This is why it makes sense to choose larger turbines.”
Designing floating platforms for efficient fabrication and assembly
Floating platforms must have a certain size to ensure structural and positional stability. “The supporting structure must absorb enormous forces, such as wind pressure, vibrations, and bending stresses,” Grytten points out. “Our big aim is to make them as light as possible to reduce material costs – for the platform steel, mooring, and cables. But we also try to make the design easy to fabricate, standardize, and industrialize, and use existing supply chains and conventional components wherever possible so they can be sourced easily.”
To find the required production capacity and resources at reasonable costs, Odfjell looks to Europe, but is also considering Asian yards. How much of the structures will be finished there depends on factors such as local steel manufacturing and fabrication cost, transport cost per tonne for the trip from Asia to Europe (e.g. stacking options on board carrier vessels), and the costs of final assembly near the destination in Europe, says Grytten. “Finding the right balance between the different options takes careful planning.”
Turning early projects into scalable floating wind momentum
For now, moving the SCALEWIND and Salamander projects through the planning stages is the primary objective. “These projects will build confidence in the technology and production,” says Grytten. Committing to DNV classification has laid the groundwork for establishing a repeatable and standardized project model and a reusable technical ecosystem for the Deepsea Star™ that will make future production at scale considerably faster, easier, and bankable.
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