Scottish wind farms: The circular answer to old turbine blades

Founded by husband-and-wife team Fiona and Steven Lindsay, who met while working for Scottish Power Renewables, ReBlade has used circular economy principles to create an answer to a waste issue that will soon see blades coming down the pipeline fast. 

Fiona Lindsay said: “Our industry intelligence has identified that, in Scotland alone, there are circa 19,000 onshore wind turbine blades. Of those, we understand that about 500 blades have already exceeded their standard 20-year operational lifespan, with thousands more requiring decommissioning over the next 10 years." 

A Reblade bench, with from left to right, L-R Steven Lindsay; Kirsty Leiper; Miles McConville; Fiona Lindsay (Image: NQ Archive)

Only last year, decommissioning began on Scotland’s first wind farm at Hagshaw Hill. More recently, ReBlade has been working with Fred Olsen at Windy Standard Wind Farm, where 36 turbines are planned to be taken down to be replaced by just eight. “That’s 108 blades being taken down,” said Steven Lindsay, “and replaced with 21 blades and at the same time doubling the generating capacity through installing more efficient, taller turbines.” 

That pattern is likely to be followed at other sites, as subsidies and leases come to an end, and owner/operators are encouraged to replant, as they say in the industry, their fields with larger more efficient turbines, through "repowering" planning applications in a drive to meet net zero targets. 

25 years on from that boom starting about 2028, is when you will start to see a whole load of sites start to be decommissioned

“It's not possible,” said Mrs Lindsay, “to say for certain when operators of wind will begin decommissioning and repowering their assets but it is fair to assume this will start to increase significantly from 2025. The aging assets of first-generation wind farms will require to be repowered to increase green energy generation and to be economically efficient and reliable.” 

The wave of decommissioning is beginning slowly but will accelerate as more windfarms reach the end of their lives. Mr Lindsay observed:  “Just as the curve of getting windfarms established began one by one, then saw plenty come online with a boom in the early 2000s, it will be the same with decommissioning. 25 years on from that boom starting about 2028, is when you will start to see a whole load of sites start to be decommissioned.”  

Financial factors will dictate whether farms keep going, as much as the physical condition of the blades. There is also likely to be pressure from landowners, whose leases will also come to an end around the same time, keen to make more money out of the next generation of more powerful turbines, rather than keep the older ones going. 

ReBlade shelter at Kingsway West, Dundee (Image: ReBlade)

Recycling and repurposing blades is also not just a UK issue. There are currently over a million blades, in over 340,000 turbines, installed across the world. Globally, the hunt is on for solutions, and ReBlade is not alone in thinking that repurposing is the answer. In the Netherlands, blades have been used to build playgrounds, and, in Denmark's Port of Aalborg, a bicycle shed was built from a disused blade. 

Until recently, the bulk of the blades that ReBlade has been working on have not been those from decommissioned farms. They are blades that have been brought down for other reasons. Mr Lindsay said: “Sometimes the blade has got a defect, sometimes the blade has been catastrophically hit by lightning.” 

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ReBlade is priming itself  so it can scale up – and looking at a minimum of 80 employees over a 40-acre site. We’re currently small,” said Mr Lindsay, “but our approach is pretty revolutionary. But the shelters that we are making are capable now of providing a scaleable solution. We have the orders and the interest for our approach to whole-site decommissioning. “ 

He added: “We will be that one-stop shop for all windfarm-derived glass resin polymer. We’re not saying that every single blade coming in will be made into large or small street furniture. Blades or parts of blades may have to go for a fibre-reclamation process, where it’s crushed and changed completely and becomes an insulation barrier or other low-grade item. But we plan to grow our capabilities and range of solutions to cope with that scale as and when it comes in." 

Fiona Lindsay with a ReBlade table (Image: Colin Hattersley)

The Lindsays are keen advocates of paying attention to the waste hierarchy. Any blade that comes in will be pushed towards its highest level of use on a hierarchy that descends from reuse through to recycling but never landfill. If there is an outlet for a second-hand blade, that will be its first, though rare, application. Repurposing and giving it a second life in structures  like shelters, will be the next. 

Another much-touted solution for waste blades is "recycling" in which processes are applied to the polymer to release the glass fibres. But Mr Lindsay notes that this is, so far, not commercially available. 

“Worldwide," he said, "there are only about five glass fibre recycling solutions and even then they involve lots of energy – energy to crush it, then energy to cook it, and then energy to bring in caustic chemicals to dissolve it. At the end what you are left with is a fibre  that is greatly compromised  which means it will ultimately end up in a lower grade and ultimately lower value product.” 

By contrast, the repurposing that  ReBlade does, adds value and represents a financially viable circular economy model. It also saves carbon, compared to other forms of disposal like shredding. The chief other low-carbon option, of simply dumping it, whole, in landfill, is now widely rejected. In 2021, WindEurope called for a Europe-wide landfill ban on decommissioned blades. 

The company has also done an independently verified lifecycle analysis and found that it is carbon positive. What it produces – for example the Dundee charging hub shelters – result in less carbon release than a comparable structure made from virgin material. 

But glass-reinforced polymer is not only a waste problem for the wind sector. It’s there in the marine sector, manufacturing, in baths and shower trays, and most of these have not looked at the problem and simply keep sending to landfill. 

The trade association Composite UK estimates that about 100,000 tonnes per year ends up in landfill. 

This is also ultimately about helping create a thriving economy through decommissioning the wind sector sustainably

A key distinction, however, of blade material is how tough and thick it is. Even shredding it, as is done with other products, is too much of a challenge. “Shredding the blades uses up a lot of energy,” said Mr Lindsay. "I broke three shredding machines attempting to do that.” 

Among the problems that ReBlade has faced is that information about the design and make-up of the blades and residual properties after their operational life, which will involce flying through the air for literally millions of miles can be hard to determine. This has meant that to produce structures, like the shelters, they have had to reverse engineer the blades, in order to ensure they are fit to be repurposed into large scale public realm infrastructure items. 

The Lindsays believe their circular solution, which encompasses a full material solution, based on site works where they will cut the blade, collect it, bring it back to their site, and then provide a full range of material solutions, including turning it, or at least parts of it, into other things, will be cheaper than any other commercial wind turbine blade decommissioning model. 

Nor are the Lindsays put off by the idea of the bigger offshore blades that will be decommissioned further down the track. The bigger blades, he observed, are now so big, at approaching 100 metres in length, that you can “literally drive double decker buses inside them”. 

However, the next generation of wind farms is also looking at a longer life, of around 40 years. 

“The ones that get talked about now,” said Mr Lindsay, "and the ones which will be established during the ScotWind process, will be big, not just big, but will probably have a different technology. There will be thicker materials and they will be stronger and heavier. I see that as attractive because we could do a lot more with them." 

He added: “Our site methodology is easy to scale up for offshore. We’re also confident that the supply chain for us in terms of parts of blades that we can’t repurpose and that we have to put into a recycling solution will be there by then.” 

ReBlade is pioneering a circular economy way of thinking that the couple hopes will spread.  

Mrs Lindsay said: "I'm hopeful operators of wind will make sustainable and circular economy-focused commitments as part of their new circular company strategies to help achieve a carbon-neutral footprint. That's where I see ReBlade stepping in.  

"We are focused on providing a carbon emission savings calculation that they can use to showcase their carbon offset through using ReBlade’s services and products. This is also ultimately about helping create a thriving economy through decommissioning the wind sector sustainably.”