Case studies
Case Study: Saint-Nazaire Offshore Wind Farm
The Saint-Nazaire Offshore Wind Farm marked many milestones. It was not only France’s first large-scale offshore wind project but also one of Endiprev’s major offshore projects. For the past six years, our teams have proudly contributed to its journey through challenges, changes, and growth.
The Saint-Nazaire Offshore Wind Farm, also known as Parc éolien en mer du Banc de Guérande, is a milestone project in France’s energy transition. Comprising 80 GE Haliade 150-6 MW wind turbines and delivering 480 MW of capacity, it is the first large-scale offshore wind farm in the country. This project is capable of powering 400,000 homes and covering 20% of the local electricity consumption.
For Endiprev, the project represents far more than a milestone in France’s renewable energy ambitions. It was proof of our technical expertise, adaptability, and global collaboration across the entire lifecycle of an offshore wind farm. Our team supported GE Vernova from factory work and installation testing to commissioning, maintenance, and remote operations.
Early Involvement: Laying the Foundation
Endiprev’s journey with the Saint-Nazaire project began long before the wind turbines were installed at sea. In 2018, we deepened our partnership with GE Vernova at the Saint-Nazaire factory. Our teams supported the production of nacelles for several projects, starting with Saint-Nazaire.
At the factory, Endiprev’s scope of work was extensive and highly technical:
- Developing method statements and LOTO procedures
- Drafting commissioning manuals
- Executing pre-commissioning
- Performing HV terminations and cabling
- Assembling generators
- Preserving nacelles
This hands-on involvement gave Endiprev unique product knowledge that would later prove invaluable in the offshore environment.
In parallel, GE Vernova entrusted Endiprev with the installation test in Antwerp Port. This was a crucial step in validating the interface between the transition piece and tower sections. Over three weeks, technicians carried out structural checks, bolt tightening verification, and cable connection tests. We identified any deviations and corrected them before offshore deployment, preventing costly delays and ensuring smooth installation later at sea.
Building on this, Endiprev was awarded a contract for Combined Test Services. Our teams provided troubleshooting support during nacelle testing, performing root cause failure analysis, and ensuring timely EHS KPI reporting. These factory-based activities not only solidified Endiprev’s reputation as a trusted partner to GE but also equipped our teams with a deep understanding of the Haliade 150 technology.
Commissioning the Saint-Nazaire Offshore Wind Farm
By 2021, Endiprev was selected as the main engineering service supplier for the commissioning of the Saint-Nazaire Offshore Wind Farm. This marked the company’s largest project to date, mobilizing more than 100 engineers and technicians.
The scope covered three critical areas:
- Electrical and High Voltage works
- Mechanical and Electrical Completion
- Commissioning of 80 GE Haliade 150 wind turbines
Endiprev’s teams had already supported GE Vernova in pre-installation tests, and now we were responsible for bringing the wind turbines online at sea. The scale and complexity of the project required precise coordination, technical rigor, and strict adherence to safety protocols in an offshore environment.
“This is yet another turning-point project for us, and we are very happy that GE Vernova has trusted in our expertise, teams, and project management skills,”
said Tiago Ornelas, Endiprev’s Business Development Manager at the time.
The commissioning of Saint-Nazaire Offshore Wind Farm not only demonstrated Endiprev’s capability to execute large-scale offshore projects but also reinforced our role as a reliable partner in France’s renewable energy future.
Beyond Commissioning: Maintenance Campaigns
Endiprev’s involvement did not end with the wind turbines’ energization following the commissioning phase, we were awarded a series of maintenance contracts to cover the full spectrum of service needs at the wind farm. Since then, our teams have continuously supported the offshore site, working on preventive, corrective, and troubleshooting scopes.
Teams per Rotation
| Year | Troubleshooting | Preventive Maintenance | Supervision | Access Means |
| 2022 | 9 technicians | 12 technicians | 1 technician | CTV – La Turballe |
| 2023 | 6 technicians | 15 technicians | 4 technicians | SOV |
| 2024 | 6 technicians | 30 technicians | 4 technicians | CTV – La Turballe |
| 2025 | 3 technicians | 15 technicians | 3 technicians | SOV |
Preventive Campaigns
In 2022, Endiprev performed the break-in maintenance (BIM) campaign, with 12 technicians per rotation. In 2023, a team of 15 technicians executed the preventive campaign from February to September. In 2024, the scope expanded significantly with 30 technicians per rotation, covering operations from April to August. In 2025, 15 technicians were mobilized again for the preventive scope. These campaigns included torquing, greasing, and rope access activities, ensuring long-term turbine performance in a demanding offshore environment.
Corrective Maintenance
Corrective works were a constant part of our involvement at Saint-Nazaire. Endiprev deployed dedicated troubleshooting teams year-round, consistently maintaining a strong presence offshore. High-voltage works were also an integral part of our role, a capability that represented both a requirement and a distinctive added value for our client.
Supervision and Site Management
Beyond field execution, Endiprev provided supervisors and site managers who supported GE with daily operations and technical coordination. This trust reflected the confidence placed in Endiprev’s expertise—not only in delivering high-quality service offshore but also in ensuring seamless project management and operational efficiency.
Navigating New Operational Challenges
While the 2023 campaigns relied on Service Operation Vessels (SOVs), 2024 introduced a new challenge: the shift to Crew Transfer Vessels (CTVs). Unlike SOVs, which allow technicians to remain offshore for extended periods, CTVs require daily transfers from land to the turbines.
This logistical change had two major consequences:
- Reduced productivity: daily transit times shorten the available working hours offshore
- Higher weather dependency: CTVs are less capable of operating in rough sea conditions, increasing downtime risk
Despite these constraints, Endiprev has relied on the adaptability and dedication of our technicians to maintain productivity and ensure campaign success. Careful scheduling, robust supervision, and close coordination with GE have been key to overcoming these operational hurdles.
Remote Operations: The Role of ROC
Complementing its offshore activities, Endiprev’s Remote Operations Centre (ROC) has played a pivotal role in Saint-Nazaire’s lifecycle. Under a three-year contract with GE Vernova, we provided 24/7 monitoring and technical support for Saint-Nazaire, along with other offshore wind farms.
For Saint-Nazaire Offshore Wind Farm specifically, 14 technicians were deployed in Nantes for six months to supervise test runs, assure turbine performance, and manage troubleshooting. The ROC team continues to deliver preventive maintenance, operational reporting, and remote interventions, ensuring uninterrupted performance.
By integrating on-site maintenance with remote monitoring, Endiprev provided a complete service chain, identifying and resolving issues quickly while supporting long-term asset reliability.
A Global and Collaborative Effort
The success of the Saint-Nazaire Offshore project reflects Endiprev’s ability to operate as a truly global and collaborative company. All Endiprev’s subsidiaries (Portugal, France, the UK, and the United States) have contributed technicians, supervisors, and project managers.
This multinational teamwork has not only expanded the technical capabilities of Endiprev’s workforce but also strengthened its positioning as a global player in offshore wind. The experience gained in Saint-Nazaire is already being applied to other projects. We brought this knowledge to Vineyard and Dogger Bank Wind Farms, both of which involve the larger Haliade-X wind turbine.
The Saint-Nazaire Offshore Wind Farm stands as a defining project in France’s renewable energy transition, and a defining achievement for Endiprev. From early installation tests to commissioning, from preventive maintenance to remote monitoring, Endiprev has been present at every stage of the wind farm’s lifecycle. The project also created 29 new positions locally, reinforcing Endiprev’s commitment to supporting regional economic development and demonstrating technical excellence, operational adaptability, and a capacity for global collaboration.
Most importantly, the project highlights Endiprev’s commitment to supporting its partners and contributing to the broader energy transition. As France pursues its ambitious goal of deploying 50 offshore wind farms by 2050, Endiprev is well-positioned to continue playing a leading role in delivering reliable, high-quality engineering services to the industry.