Researchers at the Indian Institute of Technology Mandi have claimed to have successfully used microwaves to recycle polymer composites from old wind turbine blades, using a rapid, sustainable, and comparatively eco-friendly method.

The blades of wind turbines are made of polymer composites, typically polymer systems in which fibers such as carbon and glass are incorporated for strength.

The team has developed a sustainable microwave-assisted chemical recycling (MACR) process to recycle glass fiber-reinforced polymer (GFRP) composite waste. They used microwaves to aid the chemical degradation of GFRP composites with hydrogen peroxide and acetic acid.

Both hydrogen peroxide and acetic acid being eco-friendly chemicals make the process particularly distinctive.

The researchers identified that their method’s decomposition rate of epoxy was 97.2% with recovery of the glass fibers. The recovered fibers retained nearly 99% of the strength and more than 90% of other mechanical properties than the virgin fibers.

“The recycling method that we have developed can lead to a profound shift in recycling technologies, which can help the country move towards a circular economy for wind turbine blades,” Venkata Krishnan, Associate Professor, School of Chemical Sciences, IIT Mandi, said.

India currently is the fourth largest installer of wind energy systems, with a total installed wind power capacity of 40.8 GW at the end of Q2 2022. However, India’s wind potential remains largely untapped.

The National Institute of Wind Energy’s (NIWE) recent resource assessment indicates a gross wind power potential of 302 GW in the country at a 100-meter hub height and 695.50 GW at 120 meters above ground level.

As India faces challenge with repowering old wind projects, recycling could be considered as a promising option.

When turbines can no longer be used, the de-commissioned structures of these blades, composed of glass fibers, are demolished, landfilled, or incinerated. These methods of disposal add to both environmental pollution as well as cost. It almost nullifies wind energy’s environmental benefits. Moreover, the restrictions on landfill disposal and fluctuating raw material costs could increase the costs of these composites used in wind turbine blades.

According to a report, ‘Capturing Green Recovery Opportunities from Wind Power in Developing Economies,’ published by the Global Wind Energy Council (GWEC), the wind energy sector could bring in $18 billion gross value to India’s economy.