Wind Power

07 Feb 2020

What Happens to All the Old Wind Turbines?

07 Feb 2020  by Padraig Belton   

Welcome to the wind turbine graveyard. It stretches a hundred metres from a bend in the North Platte River in Casper, Wyoming.

Between last September and this March, it will become the final resting place for 1,000 fibreglass turbine blades.

These blades, which have reached the end of their 25-year working lives, come from three wind farms in the north-western US state. Each is about 90m (300ft) long, and will be cut into three, then the pieces will be stacked and buried.

Turbines from the first great 1990s wave of wind power are reaching the end of their life expectancy today. About two gigawatts worth of turbines will be refitted in 2019 and 2020. And disposing of them in an environmentally-friendly way is a growing problem.

Burying them doesn't sound very green. Can they not be recycled?

Wind power goes as far back at least as 9th Century BC Persia, where sails were used to grind grain and draw up water on the windy Sistan plains.

Scottish professor James Blyth built the first windmill to make electricity in 1887, powering his holiday home in Marykirk.

His second powered the Lunatic Asylum, Infirmary and Dispensary in Montrose (later Sunnyside Royal Hospital).

Instead of using cloth to catch the wind like Prof Blyth and the ancient Iranians, today's turbine blades are built from composite materials - older blades from glass fibre, newer ones from carbon fibre.

Such composite materials might be light and strong, but they are also extremely hard to recycle.

That doesn't mean they have to go into landfill, according to Don Lilly, chief executive of Global Fiberglass Solutions in Bellevue, Washington.

Mr Lilly has been transforming fibreglass composites into small pellets he calls EcoPoly.

The pellets can then be turned into injectable plastics, or highly waterproof boards that can be used in construction, he says.

Mr Lilly has received interest from "several manufacturers" for his pellets.

He's also developed a programme to track blades throughout their life cycle, and make it easier to recycle them at the end.

If we "holistically think about the end of life, there are simple choices we could make now that could make fibreglass in the blade easier to recycle," says Richard Cochrane, professor of renewable energy at Exeter University.

A second avenue for recycling turbine blades is called pyrolysis.

After first chopping up the blades, pyrolysis breaks up the composite fibres in ovens with an inert atmosphere, at about 450-700C.

The process recovers fibres other industries can reuse for glues, paints, and concrete.

Other products include syngas (synthesis gas) that can be used in combustion engines. And char (charcoal) which can be used as a fertiliser.

More News