Windletter by RenerCycle – Dismantling a wind farm: all the details of a real case
RenerCycle, responsible for managing all the recovered material from the Muel wind farm, has opened its doors to share first-hand how the process unfolded.
Hello everyone and welcome to a new issue of Windletter. I'm Sergio Fernández Munguía (@Sergio_FerMun) and here we discuss the latest news in the wind power sector from a different perspective. If you're not subscribed to the newsletter, you can do so here.
Let’s go today with an edition sponsored by RenerCycle.
RenerCycle was born in Navarra as an industrial company promoted by a group of leading firms in the renewable sector with a clear objective: to apply circularity principles to the wind industry through the recovery, reuse, and recycling of wind turbine components.
Its mission is to give a second life to materials coming from dismantled wind turbines, transforming them into new resources, whether for the renewable industry itself or for other uses. All of this with the ZeroWaste goal, the company’s motto and raison d’être.
To achieve this, RenerCycle applies advanced engineering processes and innovative solutions to maximise the recovery of materials such as steel, copper, magnets, oils, and blades.
For us, it’s a pleasure to count on the sponsorship of RenerCycle, a pioneering example of circular economy applied to the wind sector, showing how sustainability can go hand in hand with industrial innovation and the creation of local value.
♻️ Dismantling a wind farm: all the details of a real case
At a time when circularity has become a key challenge for the wind industry, we have had the opportunity, together with RenerCycle, to closely follow the dismantling and material recovery process of the Muel wind farm (Zaragoza), owned by RWE, which has become a benchmark in circular economy.
The results, certified by Bureau Veritas, speak for themselves: 99.85% of the total weight of the wind turbines has been recycled or recovered for new uses — almost reaching the ZeroWaste target and positioning the Muel project as a reference in circular management of wind farms.
🌬️ A journey to the past: the legendary NordTank 600/43
Before talking about recycling, we must stop at the protagonists of this story: the 27 NordTank 600/43 turbines. In operation since 1998, they were manufactured under licence from the Danish company NordTank by the Zaragoza-based firm TAIM (Talleres Auxiliares de la Industria Minera).
They are true pieces of wind energy history and a rara avis in the Spanish market. In the case of Muel, they have provided no less than 27 years of service.
Each of these 600 kW, 43 m rotor machines holds a few curiosities we already mentioned in a previous Windletter edition: clamshell-type nacelle opening, passive aerodynamic stall regulation system, and blade tip acting as an aerodynamic brake.
🏗️ The challenge of dismantling
Dismantling turbines that were not designed with circularity in mind is a logistical and engineering challenge. There were no manuals or specific tools for dismantling, so RenerCycle had to reinvent the process while ensuring full compliance with safety standards.
For example, RenerCycle’s team needed to redesign lifting and transport tools through reverse engineering, as the original equipment was no longer available on the market.
By early July, the 27 turbines had already been dismantled and stored at RenerCycle’s facility in Falces (Navarra), where the second phase began: recovery and recycling. By the way, the dismantling work was carried out in collaboration with Tetrace.
♻️ From wind farm to raw material: Muel’s circular journey
As the company responsible for managing and tracing all recovered material, RenerCycle opened its doors to tell us first-hand, and in full detail, how each wind turbine component was handled and recovered.
🪶 Blades: one of the greatest challenges
The rotor, representing around 10% of the total weight, is the most difficult component to recycle due to the use of composite materials.
One of the main criticisms of the wind sector has been the storage of blades in landfills, an image that stuck in the public’s mind since Bloomberg published a photograph that went around the world.
But the picture has changed. New recycling and material recovery technologies are transforming how the industry manages the end of turbine life.
In this case, blades from the Muel wind farm were mechanically recycled in specialised facilities.
Meanwhile, RenerCycle and ACCIONA are advancing their joint project Waste2Fiber, a wind blade recycling plant in Lumbier (Navarra) that will allow fibers and resins to be recycled for use in new structural materials.
⚙️ Major components: value in the aftermarket
Large components such as gearboxes, generators, and hubs have a relevant market value as spare parts, especially for turbines and components discontinued many years ago. This secondary market extends the useful life of hundreds of turbines across Europe.
In the case of Muel, several generators have been sent to a Danish customer who will use them as replacements in their turbines.
In addition, to gain a more detailed understanding of component condition and potential lifetime extension, one gearbox, one generator, and one transformer are being used for detailed analysis in the R&D project R3POWER, developed with Norvento and AIMEN.
🔧 Small components, big opportunities
Small components are key to maintenance circularity. Increasingly, the industry is opting to recondition parts that, after inspection and certification, can be put back into service with full guarantees, lower cost, and reduced environmental footprint.
In Muel’s case, RWE, the wind farm’s owner, recovered more than 250 nacelle components (pumps, solenoid valves, lights) and 1,550 electrical components from control cabinets (capacitors, fuses, etc.).
All of them have been catalogued and will be reused in other wind farms in its fleet. Thus, dismantling one wind farm directly contributes to maintaining others.
For the NordTank 600/43, many components such as pumps, solenoid valves, or lights remain compatible with later NEG Micon models (NM600, NM750), opening the door to an even broader market for reuse as spare parts.
🗼 Towers: steel returning to the market
Towers account for about 70% of a wind turbine’s total weight. In Muel’s case, the steel was sent to Spanish steelworks for melting and reintroduction to the market as raw material. Steel is the world’s most recycled industrial material (>90%) and can be infinitely recycled without losing its properties.
Other internal metallic elements such as ladders, railings, or platforms, made of aluminium, have also been recovered. This metal is considered strategic by the European Union due to its role in the energy transition.
Additionally, as part of the R3POWER project, several towers are being inspected to assess their condition (from steel thickness to welds) and define new protocols for evaluation and reconditioning.
In June, the first field tests were conducted, extracting 38 steel samples that will be analysed by AIMEN Technology Centre to assess their behaviour and reuse potential.
🔌 Transformers and cables: the copper mine
Copper is one of the most valuable materials recovered during wind farm dismantling. Found in transformers, generators, and cabling, its recovery represents a high-value and strategically important flow for European industry, which remains highly dependent on imports.
In the Muel wind farm, all copper from transformers and cables was separated, classified, and sent to national foundries, where it is recycled and reintroduced to the market as secondary raw material.
🧲 Permanent magnets: the hidden treasure
Permanent magnets are among the most valuable turbine materials, and also among the most controversial, as they contain critical minerals or “rare earths”, with the supply chain largely dominated by China.
Although not all turbine types require them (depending on the drivetrain design), in these NordTank turbines they are found inside the generators, representing a small fraction of total weight but a high market value.
RenerCycle collaborates with the Canadian company Cyclic Materials to recover and reprocess the rare earths contained in these magnets. Part of the permanent magnets removed from Muel have been sent to their facilities in Canada for recovery.
Analyses of the Muel units reveal 28% neodymium and praseodymium (NdPr) and 1.48% dysprosium (Dy), all critical materials for manufacturing new motors and turbines.
🛢️ Oils: one of the greatest challenges
Managing the lubricating oils from gearboxes and hydraulic systems is a complex yet very relevant issue, one of the main challenges in achieving ZeroWaste, as they are very difficult to treat.
Within the RENEROIL4WIND project, RenerCycle and SKF are developing oil reconditioning methods to enable their reuse.
In Muel, 1,500 litres of oil have been recovered to be used in a test bench with one of the recovered gearboxes and assess its viability as reconditioned lubricant.
🔩 Bolts: the science of a second life
Although it might seem a minor component, bolts have a significant impact on both cost and material use in a wind turbine, an importance that only grows as turbines increase in size.
In collaboration with the German institutes Fraunhofer IWES and IZFP, RenerCycle has supplied structural joint bolts (rotor-hub and tower-tower) to assess their remaining life.
The tests include fatigue and damage modelling, aiming to establish technical criteria for their safe reuse. The project will also evaluate the environmental and economic impact of this practice compared to conventional recycling.
♻️ Total circularity: the path to ZeroWaste
The dismantling of the Muel wind farm demonstrates that circularity in wind energy is already an industrial reality.
The results, with an outstanding 99.85% of materials recovered or recycled, confirm that recycling or recovering nearly 100% of a turbine is not science fiction, but the outcome of applying engineering, collaboration, and technical knowledge.
The next step for the industry will be to make it faster, more cost-effective, and with greater added value in each material flow, consolidating circular economy as a standard practice in future repowering projects.
📬 Want to know more about RenerCycle?
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The Muel repowering project receives funding from the Recovery and Resilience Facility established by Regulation (EU) 2021/241 of the European Parliament and Council of 12 February 2021, through the Recovery, Transformation and Resilience Plan NextGenerationEU funded by the European Union.
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