An industry in the making: diverting wind turbine blades from landfill

Two years ago, Bloomberg published a picture of large wind turbine blade fragments being buried in earth in Wyoming, USA. ‘Wind turbine blades can’t be recycled, so they’re piling up in landfills’ the accompanying headline read. The story and image of piled-up, dusty white blades, much smaller than today’s which can reach up to 107m, was not a good look for an industry born from the need to combat climate change.

This paradox was not lost on the sector; for some time, manufacturers had been working to find solutions to a problem it knew was set to escalate. Around 25,000 tonnes of blades will reach the end of their operational life every year by 2025, this number could increase to 52,000 tonnes by 2030, according to industry trade body WindEurope.

The organisation, backed by its members, including turbine manufacturers Siemens Gamesa and Vestas, is calling for a landfill ban on wind turbine components by 2025.

“Our aim is to make them 100 per cent circular,” says Christoph Zipf, WindEurope’s press and communications manager.

At the beginning of August, the first recyclable blade, developed by Siemens Gamesa, was installed at the Kaskasi offshore wind farm in Germany, marking notable progress on this goal.

But the journey to circularity is still a long and challenging one. At present, around 95 per cent of a wind turbine – the foundation, tower and components in the nacelle, which contain materials such as steel, oil and cement – can be, and are, commonly sold into established recycling processes for profit, according to Zipf. Blades, on the other hand, are not.

They’re made of two forms of hardy plastic resins: thermosets and thermoplastics. The first forms an irreversible solid polymer that is most common and hardest to recycle, while the latter is considered simpler to remelt and recycle. Current methods available for recycling both, such as pyrolysis, which is usually conducted at or above 500°C, and mechanical recycling are considered too costly and energy intensive, however, while others are in early development phases and need to be demonstrated at scale.

Landfill, therefore, is often the only or the most cost-effective option, according to John Korsgaard, senior director of engineering excellence at LM Wind Power, a wind turbine rotor blade manufacturer. In fact, across all industries using waste fibre-reinforced plastic – used in car seats and interiors, aeroplane wings, skis, and surfboards – 60 per cent of the waste is sent to landfill.

Siemens Gamesa’s RecyclableBlade, launched in 2021, is made of a plastic resin that took five years to develop. It requires only a ‘mild’ process to break it down for recycling, according to Jakob Maennchen, team lead – casting at the company.

“Instead of energy-intensive measures [such as mechanical recycling or pyrolysis] we can put the blade into a container of acetic acid for 3-4 hours at 80°C; it’s a simple process and doesn’t require much time or many chemicals,” he explains.

Performance, quality and manufacturing are the same as its non-recyclable blades, he adds, but the material is currently more expensive, though it’s hoped it will reach cost parity over time.

The blade already has a pipeline of orders from EDF Renewables, Vattenfall and WPD, and if applied to all global offshore projects planned until 2050, the company estimates it could create more than 10 million tonnes of recyclable material.

A prototype of a 100 per cent recyclable, 62m blade, was also produced at LM Wind Power’s factory in Ponferrada, Spain in March under the €18.5m Zero wastE Blade ReseArch (Zebra) consortium.

The blade is made using a special thermoplastic resin called Elium, produced by speciality chemicals company Arkema, and a new high-performance Glass Fabrics from Owens Corning, the world’s largest manufacturer of fibreglass composites. The prototype is said to be the world’s largest thermoplastic blade ever produced.

The resin can be depolymerised – reverse manufactured back into liquid – through chemical and thermal recycling using a heating process to separate the fibre from the resin, according to its developers. The liquid can then be reused to produce new thermoplastic resins to make new blades.

The prototype is currently being fatigue tested in Denmark, and in December the recycling process will also be trialled. After this it will be offered to the market, and another test blade of the same size using different reinforcements developed.

LM Wind Power is also trialling the use of chemical recycling to turn turbine blade manufacturing waste back into raw material for new blades, an area it says the industry should tackle as a priority.

“In tonnes today it’s actually a bigger challenge, but it’s a much under-discussed issue with little understanding,” says Korsgaard. “We can see the benefits from recycling our waste immediately.”

The development of two recyclable blades is a milestone, no doubt, but just because something is recyclable, doesn’t mean it will be recycled. A report by UK Offshore Renewable Energy (ORE) Catapult states that there is a risk of producing “recyclates with no clear destination”.

It highlights that for glass fibre reinforced plastics the low price of virgin glass fibres (£2-3/kg) does not incentivise the use of recycled alternatives that may be a higher price and lower quality. What’s more, while the cost of landfill in Europe is growing and availability dwindling, much more still needs to be done to incentivise the development of the value chain.

Maennchen believes this can be achieved before Siemens Gamesa’s technology reaches its end of life.

“Our blades will be recycled after 25-plus years. Composite materials are used in a variety of industries, for products that have a much shorter lifecycle than ours, meaning an industry will be built around the reuse and recycling of these materials prior to decommissioning our blades; we want to participate in that, so we can help build out this concept and help make it viable for everybody. But it is something the whole industry needs to do together,” he says.

Siemens Gamesa is involved in a new project by EnergyLOOP, a company established by Spanish energy firm Iberdrola and industrial and commercial waste specialist FCC Ámbito, launched in May to build the first industrial-scale wind turbine blade recycling plant in Navarre, Spain. The €10m project will recycle glass and carbon fibres and resins so they can be reused in sectors such as energy, aerospace, automotive, textiles, chemicals and construction. Iberdrola and Siemens Gamesa declined to say any more about the project, such as what technology it will use.

A much smaller, £2m, three-year project is also under way in Scotland to set-up a pilot plant for recycling existing wind turbine blades. It will test and develop a thermal recycling process developed by researchers at the University of Strathclyde’s Advanced Composites Group and Lightweight Manufacturing Centre to recover glass fibre from blades that can then be reused for other products such as automotive panels and in shipping. The technology heats up the blades to evaporate the resin holding the glass fibre together.

Typically, the high heat needed in this process has damaged the material and reduced its characteristics, says Mark Robertson, project development manager of the Oil and Gas Institute at Strathclyde University. “In our new process the secret piece is that we can effectively regenerate the glass fibre back to near virgin quality,” he says.

This recovers around 80-90 per cent of the product, and the process can be used for any glass fibre waste streams. Researchers estimate they can do this at a cost comparable or lower to virgin material.

Over the next three years the consortium, which is led by Aker Offshore Wind and Composite UK and is part funded by Innovate UK, will work to scale the technology, currently a “room-sized demonstrator”, into a full-scale pilot plant located in the UK. The first milestone of the project is to have a full process design for the pilot plant, which Robertson expects will be achieved in 9-12 months.

“We expect the outcome of this project will be a proven commercial offering, from which we can build more plants wherever they’re needed. The potential supply is huge – anywhere glass fibre is used,” he adds.

Around 2.5 million tonnes of composite material are used in the wind energy sector globally.

Until today only 83MW of offshore wind capacity have been decommissioned in Europe.

But by 2050, globally this is expected to rise to 1,200GW of onshore and up to 85GW of offshore wind farm capacity (cumulatively, and assuming a 25-year lifecycle). By 2023, it’s anticipated that 40,000 to 60,000 tonnes of composite materials will be decommissioned by the wind industry (approximately 14,000 blades).

Companies looking to cash in on the opportunity are already popping up; German-based start-up Billion People says it has developed technology to turn composite fibres such as those used in turbine blades into beams for solar panels and other components.

The company recently received 50 tonnes of blade waste from the decommissioning of Vattenfall’s16.8MW Irene Vorrink Wind Farm, consisting of 28 turbines.

Chemist and company founder Dr Gregor Luthe is coy about the technology behind the process, which is supported by the co-EU-funded CarbonGreen project, other than to say it runs off electricity and has no chemical consumption, besides some additives, and the end products are fully recyclable.

Luthe says the company needs around 10,000 tonnes of composite glass and carbon fibre, which it currently gets paid to take, to scale the technology more quickly.

“We want to engage with companies that have these blades lying around – we know several energy operators and manufacturers have stored these blades for when they find the proper solution. The more we have, the better,” he adds. The long-term goal is to have processing hubs located globally.

Other companies receiving waste from Irene Vorrink include Norwegian Gjenkraft AS from which it will produce recycled fibres, synthetic oils, gas and even skis.

Eventually, Siemens Gamesa hopes that recyclable blades will be the norm, rather than the exception.

“Once there is more competition of suppliers of recyclable resins and cost comes down to a similar level as conventional resins, then it is very likely the recyclable ones will push conventional ones out of the market for many applications and conventional resins will only be used in niche applications with very special requirements,” says Jonas Pagh Jensen, sustainability specialist at Siemens Gamesa.

He believes there will be two phases for the RecyclableBlades; the current one where they’re used by choice, and phase two where they’re the default. To achieve the latter, Jensen says more competition and innovation in the supplier landscape is needed to drive down the cost of recyclable resins, along with interest from developers, regulation, and auction incentives.

LM Wind Power’s Korsgaard agrees. “The value chain needs to find ways to incorporate recycled materials into the products they supply us,” says Korsgaard. “That is why the industry want a landfill ban: to drive the creation of a value chain. It will not come without a push.”

Germany, Austria, the Netherlands and Finland have already banned landfilling of turbine blades. WindEurope says it is in contact with the European Commission to make this EU-wide, but current events, the pandemic and war in Ukraine, have stalled the issue. Though he adds “it is not forgotten”.

Of course, recycling composite materials and resins is not just a wind industry challenge. By 2025 wind is expected to account for only 10 per cent of the total thermoset composite waste stream in Europe (and 5 per cent of the total composite waste stream) according to the European Composite Industry Association. Though this hasn’t stopped wind power critics using the Bloomberg landfill pictures as a stick to beat the industry with, even if it is, for now, leading the recycling revolution for these materials.

“Perhaps it’s because we are a younger industry or because of our green image, it’s more of a focus point for us; this is not an issue that you see concerning hulls from ships, for example. I think we’ve had a higher focus on it compared to the rest of the industry in general,” says Maennchen.

The industry seems determined in its quest: since 2020, the number of projects specifically targeted to wind turbine blade recycling, covering the breadth of the value chain, have grown significantly, and most manufacturers and developers also have circularity targets.

Whatever recycling processes are commercialised, their carbon impact must also be considered, says Zipf. Eventually, he believes, sustainability will become a quality marker.

“There is a business rationale for building recyclable blades. Going forward, making blades 100 per cent circular will become a quality indicator and an important differentiator between European wind turbine technology and (potentially cheaper) non-European turbine models.”