The subsea drill system in DEME's signature green color

DEME Commissions Subsea Drill for Saint-Nazaire OWF’s XL-Monopiles

A tailormade subsea drill that will be used to install XL-monopile foundations at the Saint-Nazaire offshore wind farm has been commissioned after passing Factory Acceptance Tests on 30 September.


The drill, jointly designed by DEME Offshore and Herrenknecht, will be deployed at the French offshore wind farm site from the Innovation installation vessel.

“Never seen before in the industry, this unique subsea drill embodies our expertise in soil mechanics and offshore engineering”, DEME said in a post on social media.

The Saint-Nazaire project, being built between 12 and 20 kilometres off the coast of the Guérande peninsula in western France, will be the world’s first wind farm to use drilled XL-monopile foundations.

The 480 MW offshore wind farm, also known as Parc du Banc de Guérande, will comprise 80 GE Haliade 150-6MW wind turbines, expected to be fully commissioned in the summer of 2022.

A consortium including DEME Offshore and Eiffage Métal was awarded the EPCI contract for 80 foundations for the French wind farm in 2019 by Eolien Maritime France (EMF), a consortium between EDF Renouvelables and Enbridge. The scope includes the design, fabrication, transportation and installation of the steel foundations.

The same year, Sif received an order from Eiffage Métal for the delivery of 80 monopiles and primary steel for 80 transition pieces.

In February 2020, DEME Offshore and Herrenknecht signed an agreement for the fabrication of the subsea drill for the project.