DEME Offshore has contracted Allseas to install the offshore substation for the Yeu and Noirmoutier islands’ offshore wind farm development off France’s Pays-de-la-Loire coast. The Pioneering Spirit will carry out the job in the first half of 2024.

The “lift and set down” job of the substation jacket and topside is very similar to the Saint-Nazaire installation job Pioneering Spirit performed for DEME in the Bay of Biscay in August 2021 – Allseas’ first assignment for the fast-growing offshore wind industry.

‘We’re delighted to be providing installation services for a second major offshore wind project in France,’ says Matthijs Groenewegen, Vice President Projects at Allseas. ‘This latest award builds on our earlier successful collaboration with DEME on the Saint-Nazaire project and illustrates the important role Allseas can play, both in terms of transport and installation, in this fast-growing, sustainable offshore industry.’

He adds: ‘Weather and tidal conditions at the installation location can be challenging, which we’re able to mitigate thanks to the unprecedented size and stability of our installation vessel.’

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Consortium of wind farms

The wind farm is being developed by Éoliennes en Mer des Îles d’Yeu et de Noirmoutier (EMYN), a consortium including Ocean Winds (an ENGIE and EDPR joint venture), Sumitomo Corporation, La Banque des Territoires and Vendée Energie.

DEME, the main offshore contractor, has hired Allseas to execute the jacket and topside installation works. DEME will perform the installation of the pin piles for the substation foundations and transport the jacket and topside to the installation site.

The jacket and topside structures will be transferred to Pioneering Spirit in the field and installed directly with the vessel’s 5000-tonne crane.


Yeu-Noirmoutier is situated 16 km off the Atlantic Coast, where waters are up to 36 metres deep. When complete, the development will have a total capacity of 496 MW and produce enough energy to meet the annual electricity demands of 800,000 people.

Also read: Pioneering Spirit’s single-lift capacity to be extended to 60,000 tonnes

Pioneering Spirit

Pioneering Spirit is the largest offshore construction vessel in the world. Designed completely in-house, the vessel is designed for the single-lift installation and removal of offshore platforms and the installation of record-weight pipelines.

The twin-hulled vessel is 382 metres long and 124 metres wide. At the bow is a slot, 122 metres long and 59 metres wide, that enables Pioneering Spirit to move around a platform and lift and transport entire topsides using eight sets of horizontal lifting beams.

For jacket removal and installation, two 170-metre-long lifting beams, which can rotate on hinges, is located at the vessel’s stern. This Jacket lift system was deployed on the Ninian Northern jacket removal in 2022. Complementing the lifting systems is a 5000-tonne special purpose crane for additional lifts such as lighter topsides and jackets, modules and bridges.

In 2022, Pioneering Spirit surpassed the 330,000-tonne mark for lifted platform weight.

Picture: Pioneering Spirit in the Port of Rotterdam (by Frans Berkelaar).

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