A watershed moment for offshore floating wind turbines

Less than two decades ago, floating wind turbines were little more than a concept, with the first prototypes and approvals in principle (AiPs) hardly under discussion. Technology providers were just starting R&D projects. Equipment manufacturers were testing early demonstrators. And the first pilot wind farms were being designed. Technical, environmental and financial questions abounded as the offshore industry took its hard-earned understanding of fixed-bottom turbines and began applying it to floating turbines.

Today, floating wind turbines are making the crucial transition from pre-commercial to commercial projects, thanks to growing demand for alternative energies that can support a zero-carbon society. Early pilot farms are now being developed into commercial farms, many of which will begin production between 2025-2030. Looking beyond 2030, small-scale commercial farms will be expanded into industrial farms, with production capacities of up to 500 megawatts (MW) – enough to power a mid-sized European city.

What makes floating wind turbines different?

Fixed-bottom turbines are designed for installation in shallow water, while floating wind turbines are placed further offshore, in water deeper than 60 meters. This makes turbines for floating wind farms suited to bringing clean energy to the majority of countries that do not have a shallow coastal shelf. While costs are higher for installation, being placed far offshore also means these turbines have more consistent exposure to high-speed winds.

However, being installed in so-called “deepwater” also leads to unique obstacles. Floating turbines are subject to harsh environmental conditions and constant cyclic motion, making them prone to fatigue. Specially designed mooring systems must also be installed for floating turbines to keep them steady. This is bringing new technical and economic challenges to equipment designers, who are looking to use novel materials (e.g., nylon, polyester fibers) not yet approved for floating turbines.

The coming wave of floating wind turbines

In 2020, a series of important commercial offshore floating wind projects were announced around the world, representing hundreds of MW of power generated by floating turbines.

• The French government confirmed the construction of the first French commercial floating wind farm, to be developed in South Brittany, with a total capacity of 250 MW
• Total is partnering with Macquarie to build an as-yet unnamed offshore floating wind farm in South Korea, in the provinces of Ulsan and South Jeolla. Slated to produce 2 GW of power, the project aims to be generating at least 500 MW by the end of 2023.
• The EREBUS project, spearheaded by Total and Simply Blue Energy, will be installed on the Pembrokeshire coast in  Wales. The floating wind farm will produce 96 MW, and may be constructed by 2027.

Addressing challenges for floating wind turbines

To build safe, environmentally sound floating wind turbines, industry players brought transferable skills from fixed-bottom wind installations and fixed and floating oil and gas assets to floating assets. As project de-risking and certification have become standard for floating turbines and installations, the offshore wind industry is now looking to manage challenges across the floating wind turbine supply chain.

The price of floating wind turbines is still not competitive when compared to costs for fixed-bottom turbines, or alternative energy sources like solar power. The commercialization and increased standardization of floating turbines should help achieve competitive levelized costs of energy (LCOE) for offshore energy. But this in turn requires increased investment from governments and private stakeholders to ensure the economic viability of floating wind projects.

However, while floating wind remains the least financed of offshore wind activities, 2020 saw a major boost in public sector spending on renewable energy. Moreover, the prevailing social attitude of today favors the quick development of renewable energies. Banks and other financial institutions are increasingly turning away from carbon-heavy activities, in favor of financing environmentally responsible projects. This could potentially further reduce the cost of building floating wind turbines in the coming years.

In addition, the infrastructure for offshore floating wind farms is not yet ready to deliver large-scale, industrial-capacity turbines. Each turbine is affixed to a floating structure that is both large and heavy; constructing these foundations will require the modification of shipyards and existing facilities. Thanks to their knowledge of fixed-bottom turbines, which are built using similar techniques, manufacturers have the experience to build floating foundations. But organizing the supply chain remains complicated. Each industrial wind farm will be made up of a hundred or more turbines, each attached to multiple superstructures. Manufacturers need the infrastructure to build and store the foundations quayside, then tow the individual elements out to the offshore site.

Keeping floating wind turbine construction local

Floating wind turbines and foundations are primarily constructed from steel or concrete. These key materials are verified during the project certification process, either through independent structural modeling or to specific qualifications.

Steel has advantages as a building material, being lighter than concrete, but it is often imported, shifting construction opportunities away from local shipyards. Concrete, by contrast, can be prepared onsite by manufacturers, keeping construction local and avoiding import costs. For stakeholders looking to boost business at local shipyards when building floating wind farms, favoring concrete is a small step with big impact.

Key services boosting floating wind turbines

Construction and installation will be the major focus of the next five years of offshore floating wind turbines, as assets gear up for production. For owners and operators, this means finding ways to maximize project security and efficiency, while keeping costs as low as possible.

Bureau Veritas provides project certification for floating offshore wind farms and turbines, helping owners ensure that projects are de-risked as much as possible from end-to-end. Our experts can provide design assessment, site evaluations, load analysis, and surveillance from commissioning to installation.

Going beyond compliance

Independent of our classification and certification activities, our Global Services team offers marine warranty surveys focused on the transportation and installation of floating wind assets, providing the third party verification that is indispensable to marine insurers. Marine warranty services are a natural complement to certification, enabling project owners to satisfy requirements for all stakeholders while minimizing service overlap.

Additionally, our experts can help project developers and designers avoid delays and limit costs for wind farm construction and operations. We offer innovative assessments and technical support for hydrodynamics, load assessments, moorings, structural integrity, design optimization and installation, waiting on weather, and downtime analysis. These services are integral to moving the offshore wind industry forward at this critical time.