It is supposedly the cleanest of green technologies — but wind power has a dirty secret. When turbines reach the end of their lifespan, the blades, which are notoriously difficult to recycle, are sent to landfill.
Until now these wind graveyards have been out of sight and out of mind, too small a problem to concern us, because the vast majority of turbines ever erected are still standing. But the problem is becoming more pressing, because they were designed with a lifespan of 20 to 25 years — and many of the wind farms that sprang up in the early 2000s are running out of time.
About 600 turbines in UK waters are due to be decommissioned by 2030, according to the Offshore Renewable Energy Catapult, a government-funded research group. The number of onshore turbines coming to the end of their lives is expected to be even higher.
Durable turbine components are buried in landfill sites, such as in Casper, Wyoming, where 870 blades are stacked into 30ft deep holes
BENJAMIN RASMUSSEN/GETTY IMAGES
BENJAMIN RASMUSSEN/GETTY IMAGES
Within a decade, the agency predicts, turbine blades weighing a combined 40,000 tonnes will need to be disposed of each year, taking up as much landfill as the household waste produced annually by a city the size of Bristol. “It’s getting to the stage where the problem is imminent,” said Katharine York, in charge of sustainability at the organisation.
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Each blade from a large offshore turbine can be longer than a football pitch.
Fortunately, engineers are coming up with solutions. Off the Yorkshire coast, 120 miles out into the North Sea at the Sofia wind farm, 50 turbines have been installed in recent weeks with a new type of fully recyclable blade. Each of them towers 252 metres (827ft) above the waves, almost as tall as the Shard, in London, which stands at 309 metres.
When the wind farm is completed next year, it will power 1.2 million homes. When it is decommissioned in the 2050s, those blades will be turned into everyday items such as bicycle helmets, suitcases and car dashboards.
The blades, made by Siemens Gamesa at its factory in Hull, are held together by a resin that can be easily dissolved once the wind farm has reached the end of its life. That means the materials that go into the 108m (354ft) blades — glass fibre and carbon fibre, bound with the resin around a wooden core — can be separated and reclaimed once the turbines are dismantled. Even the resin can be reused.
Construction at the Sofia windfarm
All that is required is acetic acid, warmed to about 80C, to dissolve the resin. “That is the same thing I use to clean my coffee machine at home,” said Jonas Jensen, global head of sustainability at Siemens Gamesa. The additional cost of the new resin adds just 2 per cent to the total cost of each turbine.
Darren Davidson, vice-president of Siemens Energy UK and Ireland, said the development of the world’s first recyclable blades had been a huge boost for Hull, where the company is one of the city’s biggest employers. It has also supplied blades to Kaskasi wind farm, off the coast of Germany.
“We’ve developed the factory from nothing in the last ten years to a place where we employ 1,400 people, and we’re doing market-leading innovation,” said Davidson. “The impact that has on the community has been fantastic, and we’re really proud about what we’ve achieved. Seeing the first recyclable blades being installed in UK waters is a major landmark moment.”
Sven Utermöhlen, chief executive of RWE Offshore Wind, which runs the Sofia wind farm, said just half of the blades used at that site would be recyclable, because there was a limited supply of resin when the order was put in. Supply of the resin, which is commercially produced by third parties, has since been increased, and the company hopes that eventually its entire supply chain will be “circular”, with no waste. He said other parts of the turbines, particularly the steel towers, were already recyclable.
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This just leaves the problem of the hundreds of turbine blades already installed, which cannot so easily be separated into their constituent parts. There are various ways to tackle the problem to avoid sending them to landfill.
“One is mechanical recycling, shredding the blades into really small pieces and then mixing it into construction products, such as cement and concrete,” Utermöhlen said. “There is also a growing market for what you would call upcycling or repurposing — using them for playground equipment, furniture, bus shelters etc. But when you just look at the sheer volume being produced, the demand for repurposing probably will never be enough to really cover the issue.”
The British start-up Blue Parameters has an alternative solution for old blades, which involves cutting them into pieces and then subjecting them to heat and steam. “This allows the recovery of fibres, the resins, polymers and other chemicals,” James Scott-Anderson, the director, said. “This can be reused, with a very small percentage of waste.”
It is likely to be a far more expensive process than that which will be used on the new recyclable blades. Blue Parameters is trying to raise £185,000 to demonstrate it can recycle a single blade, and then £3.2 million to set up a processing plant in southwest England which will process 25 tonnes of waste a year. “The value for sustainability and circularity is exceptional,” said Scott-Anderson. “It puts the UK way ahead of the pack.”