Dutch offshore installation services company Van Oord has started the installation of the first of 62 jacket foundations for Iberdrola's Saint-Brieuc offshore wind farm project in France, using its upgraded Aeolus vessel.
The wind farm is located 16,3 kilometers off the coast of Brittany and has a total capacity of 496 MW.
Before installing the very first pin-piles for the jacket foundation this month, the Aeolus was upgraded and an extensive spread of project-specific installation equipment was placed on deck, Van Oord said.
Van Oord is responsible for the transport and installation of 62 jacket foundations for the wind turbines (3 pin piles each) and the 4 foundation pin piles for the offshore substation. A total of 190 pin piles will be installed.
The Aeolus was put into service in 2014. The main crane has a lifting capacity of more than 1,600 tonnes, making the vessel suitable for the transport and installation of foundations and wind turbines.
"Its advanced jacking system with its four giant legs, each measuring 85 meters and weighing 1,280 tonnes, allow Aeolus to be jacked up and to work in waters of up to 45 meters deep," Van Oord said.
Also, Van Oord said that due to the geotechnical circumstances in the Bay of Saint-Brieuc, harsh weather conditions combined with extremely strong currents, heavy Atlantic swell and very high waves, offshore operations are possible only between March and October.
"To ensure that the Aeolus can be safely jacked up above sea level the lifting spuds were modified with a flex-pin construction. For the drilling operations, new hydraulic drills were engineered and built to handle all types of soil and rock conditions. A newly designed and created state-of-the-art drilling template will function as positioning and holding tool to ensure the precise placement of the pin-piles," the company said.
Van Oord will also be deploying several other vessels on the project in the next months for the removal of boulders, installation of scour protection, transport of pin piles, etc. The installation campaign for the pin piles will be executed in 2021 and 2022. In 2022 the jackets will also be installed.
Van Oord will use the port of Cherbourg as the pin pile marshaling port. The pin piles, coming from Spain, will be stored in France before installation offshore.