From End-of-Life Wind Turbine Blades to New Raw Materials

What happens to a wind turbine blade when it reaches the end of its service life after years of operation?
This question was recently addressed in a broadcast by the Dutch current affairs programme Nieuwsuur. It is a question that will only become more relevant in the coming years, as increasing numbers of wind turbines approach the end of their initial service life.

The composites industry has been developing solutions for some time. End-of-life rotor blades can be put to new uses in several ways. The composite material can be processed into raw material for new products, while entire blades or sections of blades can also be repurposed for applications such as infrastructure.
Concrete examples of these approaches can already be found in the Netherlands. At the same time, further scaling up is needed: greater processing capacity, sufficient demand for circular products, and conditions that support reuse and recycling.
This article explores where the industry stands today, which approaches are already being applied in practice, and what is needed to take the next step.

From Rotor Blade to New Composite Product

One concrete example of a circular approach is the processing of end-of-life rotor blades into raw material for new composite products. The Polymer Engineering Research Group at Windesheim University of Applied Sciences has been researching this form of reuse for many years.
Dr. Ir. Albert ten Busschen, Associate Professor within the research group, explains that the rotor blades are first cut into smaller sections and shredded into composite flakes. These flakes can then be used as raw material for new composite products.
The recycled material is combined with a limited amount of new resin and fibre reinforcement to produce new panels and profiles, for example for sheet piling, bridge decks and guide beams for ships.
The method is already being applied in practice. Ten Busschen explains:
"Several companies in the Netherlands have now made this method operational. This means that a substantial proportion of the end-of-life rotor blades in the Netherlands can already be processed into new products."
According to Ten Busschen, research at Windesheim shows that recycled composites achieve comparable strength and long-term performance to virgin composites with the same composition.

When products made from recycled composites reach the end of their service life, they can be processed again using the same method. Ten Busschen therefore describes this as a closed loop.

More Than One Approach

The composites industry is not focusing solely on material recycling. Direct reuse also plays an important role.
For example, end-of-life wind turbine blades are finding new applications in infrastructure. Blade-Made has developed a noise barrier incorporating decommissioned wind turbine blades. Work is also underway on bridges in which the blades serve as load-bearing structural elements.

InfraBlades is collaborating on these developments with several partners, including Haskoning, TU Delft and the Municipality of Rotterdam. The knowledge and experience gained contribute to the further development of these applications and make future reuse easier.Circularity is also being advanced in other parts of the value chain. Resin suppliers such as AOC are working on raw materials from bio-based or recycled sources. NPSP and Eve Reverse are developing applications using bio-based composites, while Holland Composites and Solico are working on Duplicor applications.In addition, companies such as Curve Works and Pure Infinity are focusing on reusable moulds and reducing emissions in production processes, respectively.

From Technology to Scaling Up

The first applications are already in place, and various organisations are continuing to develop these solutions. According to Ten Busschen, expanding processing capacity is essential to applying them on a larger scale.
"This requires investment from the companies themselves, but governments and market participants purchasing these products can help by financially rewarding circularity, and therefore good LCA scores, in their procurement decisions."
Ten Busschen also points to the competitive position of non-circular processing methods. As long as options such as incineration remain relatively inexpensive, circular approaches will struggle to compete. In his view, governments can help address this through pricing mechanisms or regulation.

Efforts to close the composites loop are also underway at European level. Within EuCIA, the European Circular Composites Alliance (ECCA) brings together industry stakeholders to work on areas including recycling, collection, life cycle assessment (LCA), traceability and design for circularity.
In addition, the European REFRESH project focuses specifically on circular solutions for end-of-life composite wind turbine blades.

From a Waste Challenge to a Raw Materials Opportunity

The question of what happens to end-of-life rotor blades will remain relevant in the coming years.
The Dutch composites industry is already developing a range of solutions to preserve the value of these materials. These range from the direct reuse of complete blades or blade sections to recycling processes in which composite materials are used again as raw materials for new products.
Within the CompositesNL network, knowledge and expertise are also being brought together to help advance these developments.

Further Reading and Viewing

• Nieuwsuur | wat kan Nederland doen met afgedankte, moeilijk recyclebare windmolens?
• Windesheim, Albert ten Busschen | 10 jaar Hergebruik End-of-Life Composieten
• Compone | industrialisering van de recyclingroute voor composieten
• Blade-Made |  tweede leven voor afgedankte windturbinebladen
• Rijkswaterstaat | geluidsscherm van windturbinebladen langs de A58
• Infra-Blades | bruggen met afgedankte windturbinebladen
• NPSP | biobased en circulaire composieten
• Eve Reverse | natuurlijke vezels, biobased harsen en gerecyclede materialen
• Holland Composites | Duplicor
• Curve Works | herbruikbare/adaptieve mallen
• Pure Infinity | composiet en emissiereductie
• European Circular Composites Alliance (ECCA)
• REFRESH | circulaire oplossingen voor composiet-windturbinebladen
• EuCIA | EU Wind Innovation Cluster Hub