When wind turbine blades get old what’s next?

The cranes moved in last year at Hagshaw Hill, Scotland’s oldest commercial wind farm.

They were there to continue the dismantling of wind turbines that had been generating electricity for the last 28 years.

A similar scene can be witnessed across the world as the first wave of wind turbines built in the late 1990s and early 2000s are decommissioned.

In the case of Hagshaw Hill, the existing turbines will be replaced with taller and more efficient ones that can generate up to 10 times more electricity.

But working out what to do with the old turbines is challenging.

Between 85 and 95% of a turbine’s materials, such as steel, aluminium, and copper, can be easily recycled, but the blades are a different matter.

Made of fibreglass they are covered with a tough epoxy resin, designed to withstand years of hammering by the elements.

These durable qualities make breaking down the blades for recycling a tricky process.

Traditional solutions include using pieces of decommissioned blades in cement kilns to manufacture cement, though this can be an energy intensive process.

Blades are also commonly disposed of in landfill sites, but this option is becoming increasingly less feasible with a number of countries, notably Germany and the Netherlands, banning the practice.

Innovative solutions such as repurposing blades into playgrounds or bike sheds have been shown to be effective at a local level but, with some experts predicting up to 43 million tonnes of wind turbine blade waste by 2050, there is a pressing need for a system that will work on a bigger scale.

Scientists and start-ups are working on the problem, with many focusing on tackling the challenge of breaking down the materials used in the blades.

“At the end of life, if we’re going to get any value out of the materials, we need to be able to separate the fibres from the resin in some way or another,” Dr Claire Barlow, a sustainability and materials engineer, from the University of Cambridge tells me.