Winded: what becomes of decommissioned wind turbines?

In October 1993, Australia’s first commercial wind farm of note was constructed at Ten Mile Lagoon, west of Esperance, Western Australia. Twenty-eight years on, with wind now generating around 10% of Australia’s total electricity and 35% of its clean energy, Ten Mile Lagoon’s nine turbines are spinning towards the end of their working life, which is typically estimated at about 30 years.

They’re not alone, with several other wind farms around the country notching up more than 20 years of electricity production.

It begs the question: as turbine replacement approaches across a number of wind farms, how renewable are these producers of renewable energy?

In the main, recycling a wind turbine is straightforward, with the bulk of its tower composed of high-quality steel. For example, Danish wind-turbine developer and manufacturer Vestas, which has installed turbines in more than 80 countries, reports that its 4.2-megawatt turbines are composed of 91% steel and other metals such as iron, copper, alloys and aluminium.

But look up, and that’s where the recycling difficulties begin – in the blades.

“Blades are one of the hardest things on a wind turbine to recycle,” says Katrina Swalwell, a wind engineer and technical director at Aurecon, an engineering consultancy that’s been active in the wind industry since its inception in Australia. “They’re fibreglass, often with quite a lot of structural components in there as well.

“But most of the rest of [a turbine] is generally metals, and that is relatively easy to recycle. You’ve got to get the paint off the towers – there’s quite a lot of paint on those towers. We’ve talked to the metal recycling industry locally and there’s cost involved with that time, but it’s not something they can’t do.”

Australia currently has no facilities for recycling fibreglass, leaving the turbine blades hanging in the proverbial air. The world’s first wind farm was constructed only 41 years ago, so even international examples of recycling blades are few. But they do exist.

In December 2020, GE Renewable Energy signed the first agreement of its sort with Veolia to recycle turbine blades from its onshore wind farms in the United States. The blades are removed and cut into smaller pieces on site, then transported to a plant in Missouri where they are shredded into a material that can be used in cement manufacturing, replacing the sand, coal and clay usually needed.

More than 90% of the blade is recycled, and it’s said to result in a 27% reduction in carbon dioxide emissions.

“It’s reducing the energy you see in the in the manufacture [of cement],” says Swalwell. “And it’s also reducing the water requirements and some of the input requirements.”

As the time approaches for the earliest Australian wind turbines to be decommissioned, solutions are needed to avoid the blades and other components becoming part of landfill.

Even larger countries with significantly more turbines are struggling with the disposal options. In the US, it’s been reported that around 8000 turbine blades will come down by 2024 and already they’re piling up in landfill – Bloomberg Green reported last year that almost 900 blades had been dumped at a municipal landfill in Casper, Wyoming, alone.

How does Australia avoid this wholesale dumping of fibreglass blades – which are typically between 40 and 90 metres in length – into landfill when our turbines reach the end of their working lives?

Wind farms will be looking at one of two possibilities: extend the life of existing turbines, or await the emergence of a fibreglass recycling industry similar to that operated by Veolia in the US. Repowering wind farms – replacing the turbines – will require operators to go through the costly process of acquiring new planning permits, as well as purchasing and installing new turbine towers, so for many the most economical and practical of solutions will be to extend the life of their existing turbines.

“I think it’s going to be quite a popular option for some wind farms where the newer turbines aren’t going to sit very well,” says Swalwell.

“Wind farms that are on the end of the grid, they don’t need more power, and they can’t take more power out, so they’re pretty much going to have to repower just a few bigger turbines and the economics of it don’t necessarily stack up.

“The electronic components and electrical components are usually capable of operating for a lot longer. And things like the SCADA [supervisory control and data acquisition] and communication systems get replaced on a five- to 10-year basis anyway, just because the technology changes so quickly.

“The blades are upkept during the life anyway, so you would just be continuing to do assessments on the condition of the rest of the turbines. You might need to refurbish gearboxes, for instance.

“It’s a matter of continuing the best practices in maintenance and probably doing some extra assessments just to make sure the turbines keep operating.”

The drawbacks to lengthening the life of turbines are in efficiency and power production. Early turbines typically had a rated power of around 1.5 to two megawatts, while today’s wind wonders are up five or six megawatts.

“So you could potentially repower the site with far fewer turbines,” says Swalwell. “But it would require a completely new planning process – you have to go through that whole process still, with all of the environmental effects statements and things like that.

“So it’s that trade-off of, I’ve got a site here that is operating, presumably still making money, and it’s probably paid my loans off by now. Or do I take the risk and go through planning and repowering and potentially have a more cost-effective site.

“The cost of energy at the new farms is much lower than at the old farms. That being said, the old farms have paid their loans off, so in some ways they’re a pure asset.”

As these first-generation wind turbines approach their working lives’ end, there will be wind farms that decide to repower, replacing old turbines with the larger and more powerful towers. This hastens the need for Australia to develop an industry to recycle and reuse the fibreglass blades and other components.

A 2019 report from the European Technology and Innovation Platform on Wind Energy projected that the wind industry would be the fifth-largest supplier of fibreglass waste by 2025, but it’s still far behind industries such as building and construction and electrical and electronics when it comes to industrial waste.

The volume of materials and consistency of supply of retired blades is unlikely in itself to sustain a fibreglass recycling industry in Australia, but the wind industry is looking beyond, with ideas to incorporate other areas of fibreglass waste.

“There’s certainly lots of other industries that create composite waste that we can work with,” says Swalwell. “We’ve talked to people in recreational boating, for instance, because there’s a lot of fibreglass hulls out there. A lot of them are currently dumped – there’s not a really clear market there.

“So there is certainly a need for it, not just for the wind industry but for other industries as well. I think the fibreglass is still the major area where we’re going to need some government support.”