PhD Thesis: End-of-life of wind turbine blades – Value chain, recycling and composite materials

The recycling of wind turbine blades and of composite materials in general has been studied for the last three decades, but recycling solutions available on an industrial scale are still rare. Wind turbine blades are high performance components designed to resist at least 20 years of service life. The complex structure mainly made of glass fibre polymer composites is a challenge for recycling. As an increasing number of wind turbines are reaching end-of-life, sustainable solutions are needed. Wind energy is a renewable source of energy and it is generally expected that wind turbines should be renewable too. Nowadays, wind turbines are recyclable, up to 85%.

Experience show that the existence and the good technical performance of a recycling process do not guarantee the success of recycling. The recycling process, transforming wind turbine blade into recycled materials, is part of a longer chain of processes. An end-of-life value chain leading to recycling, however including many steps, decisions, stakeholders and framed with regulations and cost driven decisions.

The subject of this PhD is dedicated to the end-of-life of wind turbine blades. It investigates the importance of the end-of-life value chain in the establishment of sustainable recycling solutions for blades. The end-of-life value chain is described and the PhD discusses the benefit of adopting a holistic approach to facilitate the development of the recycling industry. The end-of-life of wind turbine blades is also studied through the lens of materials. Recycled materials from blades are used in the production of new polymer composite. The reinforcing effect of the recycled materials in the new composite is examined. Finally, to supplement the discussion, this PhD also investigates polymer composite materials, which are more easily recycled. Composite materials made of a biobased and biodegradable polymer named Poly (lactic acid) are produced and their potential to replace glass fibre polymer composite is discussed.