Heerema’s unusual floating turbine installation

Heerema Marine Contractors has installed the first of 27 Vestas V174 – 9.5MW turbines at the Arcadis Ost 1 offshore wind farm in the Baltic Sea, offshore Germany, using a floating installation method, which the comapnies involved said is unique.

Heerema, Vestas and Parkwind complete its first wind turbine installation using a novel floating installation method (Photo: Heerema)

The turbine was installed using Heerema’s Thialf semi-submersible crane vessel instead of the typical method using a jack-up vessel.

The plan to use a floating installation method for Parkwind’s Arcadis Ost 1 was announced for the first time in November 2019.

After almost 3 years of development and engineering, in November 2022, the companies executed the floating installation of the first Arcadis Ost 1 turbine.

Heerema said the floating installation method has two main advantages. There is zero seabed interaction, which is useful when working in areas of significant water depth or challenging soil conditions. It also has a shorter installation cycle.

Parallel operations

According to Parkwind, to speed up the installation process, assembly and lifting operations happened in parallel.

One of the Thialf’s two main cranes lifted the pre-assembled WTG-tower to the foundation, whilst the second main crane was used to pre-assemble the WTG in parallel.

Support tower

For the latter, Heerema developed a method where the Rotor Nacelle Assembly lift takes place on a support tower on board of the crane vessel.

The support tower provides a stable platform to allow a fast and secure assembly of the nacelle and the blades, Parkwind explained.

Once pre-assembled, the complete Rotor Nacelle Assembly was lifted as one piece onto the WTG tower in only one lift.

“The pre-assembly process on board the Thialf ensures full control, guaranteeing a safe and highly reliable installation environment. The reduced number of lifts between the vessel and the structure eliminates key risks of the floating installation. Vestas has delivered RNA lift-feasible components by developing new tools to support the offshore floating installation,” a spokesperson from Parkwind said.

Michel Hendriks, COO of Heerema Marine Contractors said, “This first installation is the result of extensive engineering, innovation, and the dedication of our team, alongside Parkwind and Vestas, who together have worked hard to deliver the first floating installation of a wind turbine generator using our novel RNA method. This moment is also a major milestone within the offshore wind industry.”

Wind work

The Arcadis Ost 1 is a 257 MW wind farm developed by Parkwind, located in the German territorial waters of the Baltic Sea, and will generate enough electricity to power 290,000 households. It is Europe’s first wind farm equipped with Vestas’ V174-9.5MW turbines and Parkwind’s first international project.

The offshore wind farm’s final commissioning is planned in 2023.

Eric Antoons, co-CEO of Parkwind commented, “The industry often talks about innovation. Together with our partners we create solutions for challenges that seemed impossible to overcome in the past. The floating installation method is the perfect example of what it takes to set new industry standards, and new standards mean new opportunities for offshore wind globally. Arcadis Ost 1 will soon be one of the world’s most advanced wind farms, thanks to its design, components, and installation method, all brought together by exceptionally talented teams. Now, with the first turbine installed, we trust that the project teams will successfully install the remaining 26 turbines.”