Pushing the limits of offshore wind farm installation and transportation

October 28, 2021, by savannahweeda

With the rapid increasing size of Wind Turbine Generators (WTG’s), the transportation and installation of offshore wind farms is becoming a big challenge in the complex logistics around increasing the offshore energy production. Currently the capacity is around 9MW per installed turbine, which is expected to increase to 11MW next year. Furthermore, the latest turbine models being displayed by the major manufactures will increase further to 15MW within 5 years

The challenge comes from the sheer size of the components. For example, the blades, though not relatively heavy, are heading towards 130m length, which becomes challenging to store on the deck of the ship. When considering transporting the blades transversally on the deck of a ship, the rolling motions could cause the tips of the blades to touch the water. When considering transporting the blades longitudinally, the length of the vessel becomes the limiting factor.

Furthermore, the next generation nacelles are expected to weigh up to 1000 tonnes, and have to be hoisted to heights of up to 150m above sea level. The ships currently used to transport and install WTG’s were designed for turbines of about 3MW, which would weigh around 150 tonnes and had to be hoisted to 80m above sea level. This development has occurred very fast, in less than 5 years, which is a fraction of the lifespan of a typical vessel. To keep up with this progress, vessels have had to go through multiple updates since launch so they can still be utilized in the latest installation of wind farms.

New opportunities

With the American offshore wind market opening up, many new opportunities will arise which will also bring their own new challenges. The approach in Europe is to mobilize in the closest port to the location of the wind farm. This becomes a hub for the nacelles, blades and tower subparts. Getting the components to and from the mobilization port involves careful consideration, for example with respect to port opening and quay strength. In Europe, this does not involve sailing long distances, as these components come from other European ports. For the offshore wind market in the United States, shipping these components across the Atlantic will probably become more relevant, and not many ships are up for this task.

Finally, with an eye set on the future, the maintenance and decommissioning of WTG’s will increase in importance. This opens up the opportunity for retrofitting existing vessels or designing and building new ones fit for purpose. The demands for decommissioning are not the same as for commissioning wind farms, resulting in further opportunities for innovations and creative solutions.

Blades onboard the aft of an offshore installation vessel
on racks designed and engineered by DEKC Maritime

DEKC Maritime has been involved in all the challenges the offshore wind industry has presented, from upgrades of offshore wind farm installation vessels, to the ground up design and engineering of installation vessels, support vessels, turbine transport vessels, rock-dumping vessels, cable layers, dredgers, etc. In addition, solutions for rock-dumping, cable laying and grouting operations are also designed in-house at DEKC. This is carried out with the state-of-the-art tools available in our repertoire, such as the calculation of structures through FEM, parametric hull shape optimization by CFD, stability optimization with NAPA programming and an optimal design and layout through the usage of a 3D environment in every engineering stage.

Given these requirements, DEKC Maritime has been looking closely at what the design of the next generation vessels will look like for the offshore wind industry. These include transport vessels, WTG installation, crew transfer vessels, and wind farm support, maintenance and decommissioning. With a focus on fuel and cost efficiency, high reliability, and good workability characteristics, we believe we have the right tools for the job! Furthermore, with careful regulatory consideration and with our experience in the sector, we have multiple starting points we would like to walk through with our clients to be at the forefront of the growth in this sector.

Let us discuss what we can do for you at stand 1.315 at the Offshore Energy in Amsterdam.