Managing maintenance for offshore wind turbines

At the crossroads of cutting-edge technology and artificial intelligence, from the site in Pau, TotalEnergies deploys a range of expertise to ensure the complex maintenance of these offshore giants. How is their availability optimized? What exactly is “weather delay”? Why do predictive scenarios need to be developed? Guillaume Clément, Offshore Wind Operations Engineer, gives us some of the answers.
 

Guillaume Clément, you are responsible for Operations & Maintenance issues for Offshore Wind projects in the development phase at the CSTJF in Pau. What does your job consist of?

Guillaume Clément: I’m involved right from the study phase, to define the operational strategy and calculate the operating costs (OPEX) of wind farm projects. I also assess the availability of the future assets. Ideally, we’d like our wind turbines to operate continuously but, in practice, we have to work around unexpected events. My job at TotalEnergies therefore involves accurately estimating the "availability time", incorporating the preventive maintenance periods and repair time. It’s a key indicator as it has a direct impact on power generation.
 
 

What kind of failures do you come across?

G.C: To keep it simple, there are two main categories of failures: those that can be repaired directly on the wind turbine without using external lifting resources, and those that require a more complex operation involving specific lifting resources, such as Major Component Replacement (MCR) operations. These may include large components such as the blades, the gearbox or the generator. In cases like that, we bring in a jack-up vessel to lift the component out so it can be replaced.
 

They sound like complex operations…

G.C: Complex and costly, yes! To really understand the challenges involved, you need to understand how a wind turbine works. Above the surface, it’s basically a turbine and some blades, but that’s just the visible part of the iceberg. Underwater, a network of cables links each wind turbine to an offshore electrical substation, which in turn is linked to the coast via an export cable. This configuration requires a lot of different technical experts to ensure the maintenance of these offshore giants. 
 

What about marine logistics?

G.C: Well that’s also a key issue because accessing offshore turbines is a challenge in itself. To maximize availability, we have to choose the most suitable transport and transfer methods, a light vessel with transfer to a landing stage, an offshore service vessel with transfer via a motion-compensated gangway, by helicopter and winching a personnel transfer basket, etc. We also have to incorporate the “weather delay” into our scenarios, i.e. the delay owing to poor weather conditions which hinder the deployment of logistic resources. It’s a step that requires a lot of forward planning, right from the design phase, to ensure that our assets are shut down as little as possible, irrespective of the geographical area. From Pau, I'm currently working on Asia, but we also have other developments under way in Europe and the United States.
 

How can these new technologies help optimize this kind of operation?

G.C: We’re currently working on predictive scenarios so that we can anticipate failures as much as possible. Thanks to artificial intelligence and the latest industrial monitoring technologies, we can improve failure predictability. Using drones for example helps us conduct advanced inspections on sites located far away or which are difficult to access.
More broadly speaking, we draw on the years of expertise at TotalEnergies, which have been its strength for decades now. For example, the Company has unique know-how in marine and subsea logistics. It is among the most advanced when it comes to using subsea inspection robots, thanks to the experience acquired by the Exploration & Production branch. It also has a whole battery of digital tools that allows it to be agile across a wide range of topics: managing geotechnics, operational excellence, or the development of major projects throughout the world. These different areas of expertise are all springboards to support the development of offshore wind!
 

Talking of projects, the Culzean project in the North Sea is now a reference…

G.C: I am very familiar with this TotalEnergies project as I was in charge of the Maintenance Operations for it during the engineering phase. With the water depth being too deep - over 85 meters - to install a wind turbine with foundations fixed on the seabed, we installed a floating wind turbine! A feature that makes the project particularly innovative and fascinating from many aspects. It provides a new inroad into the decarbonization of our activities by supplying the Culzean gas platform with green energy, and raises unprecedented challenges in terms of maintenance and R&D. We’ve mastered the technology on onshore and fixed offshore wind turbines, but how can we adapt it to more powerful (+15 MW) floating offshore wind turbines? Emerging solutions are giving us opportunities to anticipate and model different scenarios.
 

What are your mid-term objectives?

G.C: TotalEnergies is massively investing in onshore and offshore wind. Our ambition is clear - to be a reference wind energy operator! The O&M offshore team in Pau works on a daily basis to reinforce its expertise and achieve the ambition in the short term. As for myself, I’m taking advantage of the "wind of innovation" that is blowing through the CSTJF, among all the interdisciplinary teams, to make progress on strategic topics related to the efficiency of production operations for wind energy.