In 2021, Danish partners launched DecomBlades to recycle retired wind turbine blades. 5 years later, 40 tonnes of recovered glass fibre had entered new blades in Taiwan

A retired wind turbine blade is not an easy piece of waste to deal with. Built to withstand decades of wind, weather and constant movement, its composite materials are also difficult to separate once the blade reaches the end of its working life. A Danish-led project has spent the past five years tackling that problem, turning material from old blades into components for new ones.

The project, known as DecomBlades, was launched in 2021 by partners from across the wind industry value chain. Its work has focused on finding practical ways to recover valuable materials from blades that would otherwise face increasingly difficult disposal challenges.

One result has now moved beyond the laboratory and into commercial wind turbine production. Siemens Gamesa has used 40 tonnes of recovered glass fibre from decommissioned blades to manufacture new 115-metre-long turbine blades for Ørsted's Greater Changhua 2b and 4 offshore wind project in Taiwan.

Why are old wind turbine blades difficult to recycle?

Wind turbines are designed for long service, with blades commonly remaining in operation for 20 years or more. Their strength comes partly from composite construction, where materials such as glass fibre are embedded in resin to create a lightweight but durable structure.

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That durability becomes a challenge at the end of the blade's life. Unlike materials that can simply be melted down and reshaped, composite blades contain different materials that must be separated before they can be effectively reused.

DecomBlades brought together companies and organisations across the industry to explore ways of recovering those materials. The aim was not simply to find a way of getting rid of old blades, but to return useful material to the manufacturing cycle.

How does the DecomBlades process recover glass fibre?

One of the approaches developed through the project uses pyrolysis. In simple terms, the process applies high temperatures to break down the resin surrounding the reinforcing fibres, allowing the glass fibre to be recovered and processed again.

The recovered fibres can then be remelted and turned into new, high-quality glass fibre. That material has subsequently been incorporated into new wind turbine blades, creating a link between an older generation of turbines and new renewable-energy equipment.

The significance lies in that closed material loop. Instead of treating a retired blade as the final destination for its materials, part of the blade can become a resource for another generation of turbines.

What happened to the recycled material in Taiwan?

The clearest demonstration of the approach is in Taiwan, where 40 tonnes of recycled glass fibre were used by Siemens Gamesa in the production of new blades.

Those blades measure 115 metres in length and are being produced for Ørsted's Greater Changhua 2b and 4 offshore wind project. The scale of the blades makes the recycled-material achievement particularly tangible: material recovered from decommissioned equipment has been incorporated into components destined for another large offshore wind development.

For an industry built around the rapid expansion of renewable electricity, the issue of what happens to equipment after decades of service is becoming increasingly important. Recycling solutions therefore address a different stage of the wind industry's lifecycle than simply building more turbines.

Can a material passport make blades easier to recycle?

DecomBlades has also worked on a less visible part of the recycling problem: information.

The partnership developed industrial material passports for decommissioned wind turbine blades. These documents record the materials used in a blade and identify their precise locations, giving recycling companies information they can use when dismantling and separating components.

That information can make the recycling process more targeted. Rather than treating an entire blade as one unknown composite structure, recyclers can use the passport to understand what is inside and where particular materials are located.

The system is intended to remain useful long after a blade leaves the factory. When a turbine reaches the end of its service life, the wind farm owner is expected to provide the material passport to the companies responsible for decommissioning and recycling. Blade manufacturers can also make the documents available online so recyclers can access them when needed.

What does this mean for the future of wind turbine recycling?

The DecomBlades project shows that blade recycling involves more than developing a single technology. Recovering material is one part of the challenge; knowing what a blade contains and where those materials are located can also determine how efficiently it can be dismantled and reused.

The 40 tonnes of recycled glass fibre used in Taiwan provide a concrete example of what that approach can achieve. At the same time, material passports address a more fundamental issue by carrying information about a blade throughout its lifecycle.

Wind energy has expanded around the need for long-lasting infrastructure and lower-carbon electricity. As the first generations of modern turbines approach retirement, the industry's environmental footprint will increasingly depend not only on how turbines generate power, but also on what happens to their materials afterward. DecomBlades' work points toward a model in which retired blades are treated less as waste and more as a source of materials that can return to the same industry.