Deme Offshore installs ‘largest ever offshore wind monopile foundations’

257MW Arcadis Ost 1 Arcadis Ost 1 (257MW) Offshoreoff Rügen, Mecklenburg-Vorpommern, Germany, Europe Click to see full details is located in the German Baltic Sea off the island off Rügen in water depths of up to 45 metres and with challenging soil conditions. The project is due to be supplied with 27 Vestas V174-9.5MW wind turbines later this year.

According to the company, the 28 XXL monopiles are the largest monopile foundations ever to be installed, weighing more than 2,000 tonnes each, with a diameter of 9.5 metres and a length of up to 110 metres.

Deme’s Orion installation vessel used its DP3 system to install the foundations. This dynamic positioning system provides the vessel with stability on the water and enables it to continue operation even if an active or static component fails.

The Orion runs on LNG and is equipped with a 5,000-tonne crane and a motion-compensated pile gripper system. The gripper system enables the crew to upend and drive the monopiles, which are then transported horizontally on deck. The system, combined with the vessel’s DP3 capability, keeps the monopiles vertical and stable offshore despite waves and vessel motions.

A new set of specialist tools were added for the project, including an adjustable monopile sea fastening system, a newly-built automated monopile lifting spreader beam to enable the horizontal lifting of the XXL monopiles, automated quick-lifting tools to avoid manual handling on deck, as well as several new noise mitigation systems.

Arcadis Ost 1 is being developed by Parkwind with PMV and OstseeWindEnergie, a project company consisting of Oberhessische Versorgungsbetriebe, Stadtwerke Bad Vilbel and WV Energie.

The wind farm is due to begin operations in 2023.