"WE have close to 12,000 turbines in the UK at the moment. That means, plus spares, well over 30,000 blades. You've got to double it, triple it, quadruple it."
As Professor Paul de Leeuw explains, Scotland and the wider UK’s rapidly growing wind energy industry has already left us with “a bucket load of stuff” – and the question of what to do with it after it's no longer fit for purpose.
And De Leeuw, the director of Robert Gordon University's Energy Transition Institute, said the number of turbines was only going up.
“If you look at the targets for the Government, they want to double onshore wind – so from 15 gigawatts to 30 by the end of this decade – and they want to quadruple offshore – so we'll go from 15 to about 55 gigawatts."
Why would Scotland have wind turbines that need scrapping?
An original equipment manufacturer – OEM – will often set up a contract with a new wind farm to provide full services of those turbines for 10 years. That leaves at least 10 more years when an operator may choose to “self perform”, taking on the maintenance and repair of the turbines themselves. But the OEM may stop making the old turbine model and parts for it altogether.
Marc Hickling, an engineering project lead with Canada-based Utilities Kingston, says that is quite common.
“It's such a quickly moving market that you end up with obsolescence really, really rapidly,” he says. “It's ridiculous. There's obsolescence like every five minutes.
“I'm actually standing in front of five inverters that have been shipped to me because the OEM doesn't want to support it anymore, even though the OEM still exists.”
James Barry, the chief executive of Scotland-based Renewables Parts, explains that operators must decide whether to “sweat the asset, just keep running it for as long as possible and make as much money as possible” – or “replace it with this much [newer and] bigger turbine which can generate more power, more revenue”.
Repowering or replacing?
Repowering, Hickling says, is “basically upgrading” – and is more common in North America than Europe.
“They replace something like 80% of the turbine,” he says. “You rip out the gearbox and refurbish it, rip out the converter and refurbish it, upgrade the blade, if it's a 2-megawatt turbine, you turn it into a 3-megawatt turbine.
“By repowering, you're extending the life by another 20 years.”
The second option is completely replacing the turbine, using the infrastructure already in place to provide more power than the old one did.
“It's almost plug and play if you get it right,” de Leeuw says. “The beauty of what we have is most of the cabling is in place, the substations, it's already there.”
What about the old wind turbines?
Whether repowering or replacing, the question of what to do with the old turbines – or all the old parts – has not gone away.
Barry says that one simple option is “that they could be removed and replanted somewhere else”.
“Many turbines have found their way into other countries,” he says. “Africa has a lot of second-hand turbines, Eastern Europe, even in Scotland, right here, we have reused turbines and that's very viable depending on what you want to do.”
The second idea – which is clearly less desirable for an industry built on green credentials – is to simply send the turbines to landfill.
Both Hickling and Barry independently raise images of blade “graveyards” in the US, where old turbine parts are simply abandoned – and sometimes even buried.
“Tens of thousands of aging blades are coming down from steel towers around the world and most have nowhere to go but landfills.”https://t.co/ivbh6HrfDY#EnergyTransition #ClimateActionNow #NetZero
— Art Berman (@aeberman12) August 15, 2022
Five years ago, this issue made headlines, with Bloomberg reporting: “Wind turbine blades can’t be recycled, so they’re piling up in landfills”.
However, de Leeuw says this is not necessarily the case.
“If you actually look at what the industry is saying, they think about just over 95% of [a turbine] already you can recycle,” he says. “The copper, the steel, all the bits and pieces of recycled plastic, they're absolutely fine.
“The big challenge we currently have is the historic stuff we installed, particularly the blades. The product is fibreglass. It's great stuff to make things from. It's very hard to recycle.”
The professor says there are four main things which can be done with these old blades:
- 1: Mechanical recycling. De Leeuw calls this “the easy one”. Cutting, grinding, and repurposing materials into low-grade products like concrete or asphalt.
- 2: Burning the blades for energy. “It's not a particularly clever way of doing it, but you can basically burn it,” the professor says.
- 3: Chemical processing which can remove plastic to salvage glass fibres. But, de Leeuw says: “Nobody does it. It's too expensive, too complicated. It's a lot cheaper to make glass fibres.”
- 4: Creative repurposing, such as noise barriers, shelters, or bike stores.
With thousands of blades already in use and many more to come, the question of what to do with outdated or obsolete parts is increasingly urgent.
As Scotland pushes forward with ambitious renewable energy targets, finding sustainable solutions for turbine decommissioning will be essential to maintaining the industry's green credentials.
