One of the world’s largest wind turbine manufacturers says it has a potentially game-changing solution to the industry’s huge plastic waste problem. Last week Vestas announced that it had found a novel way to break down the plastic in turbine blades into virgin material. This way, instead of clogging landfills, it can be recycled to make new turbines.
Here’s why it’s a tall order – how literally colossal. Modern turbines with blades longer than the height of the Statue of Liberty are quickly conquering land and sea. They’re super tough and built to withstand the elements for decades. But once they are decommissioned, they usually become waste. By 2050, turbine blades are expected to become 43.4 million tons of waste.
“It could be really big.”
Vestas has so far revealed very little information on how its new technology reclaims the plastic used to make turbine blades. But if the company can do that, it would be a game changer for the wind industry, especially as there are major challenges ahead.
“It could be really big. But, as they sometimes say, the devil is in the details,” says Steven Nutt, professor and chair of composites at the University of Southern California’s Viterbi School of Engineering.
First of all, the turbine blades are not made of ordinary plastic. Vestas says it found a way to recycle epoxy, which is like plastic on steroids. It was chemically engineered to be nearly indestructible. Of course, that makes it difficult enough to make parts for airplanes, spacecraft, and wind turbines.
To understand how tough this stuff really is, we need to get into the chemistry a little. Most other plastics that we encounter in our daily lives can be melted and reshaped. Epoxy is different. It is a so-called “Duroplast”. During the curing process, its chain molecules form almost unbreakable bonds, so-called cross-links. As a result, epoxy retains its shape and chemical structure even at high temperatures and extreme conditions. Think of it like cooked egg whites, Nutt explains: Once heated, cooked egg whites no longer become liquid.
“Plastic on steroids”
“[The material in turbine blades] has been optimized over decades to last as long as possible, even in extreme weather conditions…this focus has also led us to believe that it is impossible to recycle,” says Mie Elholm Birkbak, Innovation Concepts Specialist at Vestas, told The edge. “But now we have found a technical key to unlocking this potential.”
This key is a chemical process that Vestas discovered during its collaboration with Aarhus University, the Danish Technological Institute and epoxy manufacturer Olin. The first step is to immerse the blade in a liquid that separates the epoxy from other materials, which are usually glass or carbon fibers. In the second step of the process, the epoxy is treated again to break it down into its chemical components. The result, according to Vestas, is a new epoxy resin that can be reused to make a new turbine blade.
So far, the company has only been able to demonstrate this process on a small scale using “pieces of turbine blades”. After a few years, says Birkbak, “we expect to have an understanding of what that will look like on an industrial scale.” Vestas is working with Olin and recycling company Stena Recycling to scale up this pilot project.
There are still many big questions to be answered. First, Vestas says its process can recover a “majority” of the epoxy in old blades, but the company doesn’t have specific numbers to share at this time. And Vestas won’t say how many times the epoxy can be reused by the new chemical process it has developed. So it’s unclear if this just extends the life of the material rather than making it infinitely reusable.
There are still many big questions to be answered
A typical turbine has a lifespan of about 20 years. Once his blades can be reused, it could keep him out of the landfill for a few more decades. But if the chemical recycling process can’t be repeated over and over again with the same material, just kick the can down the street a little before sending it to a landfill.
A common misconception about recycling is that plastic can always be recycled. Even flexible plastic is difficult to reuse. Only 9 percent of this has ever been recycled in the history of plastic. Most of the time, plastic is “downcycled” – turned into an inferior product – because the quality degrades each time the material is reheated. And devices made from recycled plastic often need to be reinforced with lots of virgin plastic, a limitation that can only ultimately lead to more waste.
Vestas also doesn’t say what chemicals it intends to use in the process, other than describing them as commodities that are “readily available and relatively cheap,” according to Birkbak. As Vestas scales up, it must ensure that these chemicals do not create their own environmental problems.
The company also needs to figure out what to do with residues other than epoxy. Turbine blades are made from a mixture of epoxy and glass or carbon fibers. These fibers typically make up half or more of the material. So in order to recycle the entire blade, the company has to reclaim everything. In addition, all of these recovered materials would need to be competitive with virgin material.
Still, the growing wind industry has to figure out what to do with all the old turbines. In Europe, turbine blades were used to build bridges. Blade material can also be used to make cement. But these solutions, while promising, still resort to downcycling.
Vestas, on the other hand, hopes to have found a truly circular solution to the wind energy waste problem. If successful, the new technology could even be used to breathe new life into turbines that have already been discarded. And it could potentially save epoxy used in aerospace and other industries as well.
“I’m pretty excited about it. Just because, you know, Vestas kind of stuck its head out here,” says Nutt. After all, Vestas is a giant in the wind industry.
“It’s a great development for the industry that some of the big manufacturers are trying to be more sustainable,” said Aubryn Cooperman, wind energy researcher at the National Renewable Energy Laboratory.