Recycling of end-of-life wind blades through renewable energy driven molten salt pyrolysis process
Wind power is one of the most promising pathways for a future fossil-free society due to its abundant resources and continuously decreasing costs. From 2013 to 2022, the global total installed capacity has grown 3 times from 300 GW to 900 GW. In Sweden, wind power has become the third largest electricity source since 2013, and its installed capacity has reached 12.1 GW by 2021. However, wind turbines themselves present another environmental issue when their useful life is over, since they will become a form of hazardous waste that cannot be decomposed naturally. Especially the wind blades, they are mostly made of glass fiber reinforced plastics (GFRP) and can be longer than 60 m. On a global scale, it was expected that the total annual amount of end-of-life (EOL) wind blade can reach 683 ktons in 2025. In Sweden, the cumulative number of installed wind turbine has reached 813 by 2005. Based on the 20 years’ average life time for wind turbines, there will be more than 2400 pieces of wind blades need to be disposed by 2025. With the rapid growth of wind turbine installation after 2005, EOL wind blade will increase dramatically in the near future in Sweden, which is challenging the Swedish wind energy companies and recycling companies.
Background
Due to the nature of the GFRP materials, wind blades are technically difficult to re-process and convert into new valuable materials. In addition, due to the large size of the wind blades, it is also costly to transport and cut these EOL wind blades. Therefore, in most of cases, landfill and incineration are still two major disposal ways for the EOL wind blades, which could potentially cause serious environmental impacts. During past years, other recycling methods also have been explored, which can be classified into three categories: mechanical, thermal and chemical. However, they are either complicated, energy consumption, high cost or failed to obtain high value end products. So far, industrial scale recycling solutions for GFRP composites are still rare or non-existent in most regions, e.g. Sweden. Recently, at national level, many European countries started to forbid composite waste, including EOL wind blades, from being landfilled. At company level, Vattenfall has committed to landfill ban and to recycle all wind turbine blades by 2030. Therefore, developing cheap, clean and efficient EOL wind blade recycling processes of great significance to the wind energy industry and society.
Aims and objectives
The project aims at developing a renewable energy driven molten salt pyrolysis process for achieving a cheap, clean and efficient EOL wind blade recycling process. The new process can be directly integrated with renewable energy systems (e.g. solar, wind power) without extra electricity storage facilities. The levelized cost and potential carbon footprint per kg of the EOL wind blade material of new recycling process should be significantly lower than the traditional thermal pyrolysis process. The process will be developed based on a close collaboration between two departments of KTH and Vattenfall.
Outcomes
Publications coming out of this project will be available through Diva
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