Researchers use microwaves to recycle polymers to make wind turbine blades

New Delhi: Researchers at the Indian Institute of Technology, Mandi have used microwaves to recycle polymer composites to make wind turbine blades in a rapid and eco-friendly manner, according to officials.

This method is rapid and sustainable compared to currently used methods like landfills and thermal-based recycling, they said.

The findings of the research have been published in the Resources, Conservation and Recycling Journal. According to the team, there is a worldwide impetus to adopt renewable sources of energy such as wind energy to overcome the drawbacks of fossil fuel-based energy.

India is the fourth largest installer of wind energy systems and as of July 2022, its total installed wind power capacity was 40.893 GW. Wind power is harnessed through the installation of wind turbines (windmills) in strategic areas in the country. The blades of these wind turbines are made of polymer composites that are polymer systems in which fibres such as carbon fibres and glass fibres are incorporated for strength.

"We have developed a sustainable microwave-assisted chemical recycling (MACR) process to recycle glass fibre reinforced polymer (GFRP) composite waste. Also, we used microwaves to aid the chemical degradation of GFRP composites with hydrogen peroxide and acetic acid.

"Both hydrogen peroxide and acetic acid are eco-friendly chemicals, the former used extensively as a disinfectant or antibiotic and the latter being vinegar," said Sunny Zafar, Assistant Professor, School of Mechanical and Materials Engineering. Zafar explained that at the end of the service life of the wind turbine blades, the de-commissioned structures made of glass fibres in epoxy polymers are demolished and either landfilled or incinerated.

"Both methods of disposal add to environmental pollution and cost. It is predicted that about 2,00,000 tons of composite waste would be generated by wind turbine blades between 2024 and 2034 all over the world. This negates the environmental benefits offered by wind energy. Furthermore, restrictions on landfill disposal and ?uctuating raw material costs could increase the costs of these composites used in wind turbine blades," he said.