Over the clouds: Successful wind projects at a 1000m altitude

Sambrès, Bois de la Serre and Monts de l’Ain wind farms, France

The three wind farms of Sambrès, Bois de la Serre and Monts de l'Ain, with a total capacity of 92 megawatts (MW), developed and operated by Renewable Energy Systems Ltd. (RES), share one common characteristic; they are located in a forested and mountainous area at around 1000 meters altitude. This specific characteristic makes these projects more complex to manage, a challenge that Senvion has met head on. To accompany RES in the successful realization of their wind farms, Senvion proposed flexible and tailor-made solutions at the early engineering phase of these projects.

Site specific hub heights respecting sites constraints

It all started with the Sambrès and Bois de la Serre wind farms, located in the French Southern mountain called “Montagne Noire”, for a total of 37 wind turbines. RES was looking for efficient and performing wind turbines that fit the site features: strong and turbulent wind with height constraints regarding the hub height as well as the tip height. In regards to Sambrès, the maximum tip height is 130 meters and 85 meters for the hub height. At Bois de la Serre wind farm, the maximum tip height is 135 meters.

Aurélien Tasse, Project Engineer at Senvion Europe South West explains: "Due to the many different height constraints and wind classes of these sites, the most suitable wind turbines are the MM82 and the MM92 for optimum yield. However, we needed wind turbines with 85 and 88.5 meters hub heights that are not standard heights in our product portfolio. The Senvion R&D department produced feasibility studies and these hub heights have been specially customized and certified for these sites. RES was delighted with this site specific development."

Five different hub heights to optimise the energy production

The flexibility and receptiveness of Senvion’s team motivated RES to continue this partnership for the Monts de l'Ain wind farm, located on a ridge at nearly 1000 meters altitude in the Bugey mountain. For this site, the nine wind turbines could not surpass a height of 1120 meters. Therefore, Senvion's Project Engineering team integrated all the different constraints of the site to find the optimum configuration. Aurélien Tasse specifies: "Given these constraints, we proposed five hub heights and two different rotor size turbines amongst the nine wind turbines destined for the wind farm. Minimising the deforestation was also a requirement, therefore a single blade installation was necessary. We have developed a new single blade mounting tool for the MM100 wind turbines, a tailor-made solution!"

RES is convinced that Senvion’s agility will prove essential for optimised and competitive projects in the current energy transition market.
Catherine Marshall Contract & Purchasing Manager at RES

Catherine Marshall, Contract & Purchasing Manager Wind turbines at RES expresses: “RES is committed to striving for optimised solutions, specific to project constraints and often combined with challenging climatic conditions. Senvion’s Project Engineering and R&D teams have often risen to this challenge, in both the development of project specific towers or in the improved robustness of existing wind class certifications.  RES is convinced that Senvion’s agility will prove essential for optimised and competitive projects in the current energy transition market.”

The wind farms of Sambrès and Bois de la Serre, located in the French departement of Aude, are respectively comprised of 26 MM82 and 11 MM92 wind turbines. The Monts de l'Ain wind farm, in the Auvergne-Rhône-Alpes region, consists of 4 wind turbines MM92 type and five MM100 wind turbines. Together, the wind farms are now producing green electricity for nearly 95,000 French residents.

© Photos: Renewable Energy Systems Ltd.