Old wind-turbine blades are getting a new lease on life—in cement.
Turbines are mostly made of steel, a widely recyclable material. But their blades are constructed of complex composite materials such as fiberglass and balsa wood that are difficult to separate and process, presenting a recycling challenge. As a result, blades that reach the end of their lives often end up in landfill.
Last year, more than 12,000 blades were scrapped globally, according to data provider BloombergNEF, which expects the number to exceed 28,000 in 2030. This could result in hundreds of thousands of metric tons of waste each year. Turbine blades can last 20 to 30 years, but companies often replace them earlier with more efficient designs.
Some companies have gotten creative when recycling old blades, repurposing them as slides and climbing frames in playgrounds or as noise barriers for highways. But these niche uses are unlikely to account for all the worn-out hardware.
Instead, old blades are increasingly being sent to cement factories, where they are burned in kilns to make clinker, a key ingredient in the building material.
Danielle Merfeld, chief technology officer at the renewable-energy division of General Electric Co. , said the cement industry is currently the best large-scale alternative to landfill. “Blades are big and we are talking hundreds and hundreds of blades, but people use a lot of concrete,” she said.
Cement manufacturing is one of the largest sources of carbon-dioxide emissions. Cement’s key ingredient clinker is made in kilns that burn and mix ingredients in an intense 1,450-Celsius heat. Kilns typically burn conventional fossil fuels, but companies are increasingly using waste such as plastics and car tires—and old wind-turbine blades—instead. They say incinerating waste keeps it from going to landfill sites and lowers emissions.
The European Union’s cement industry is already using alternative materials such as waste and biomass for 50% of its fuel, and that figure could eventually reach 95%, according to the European Cement Association. Some industry experts have raised concerns about turning waste into fuel, saying it undercuts recycling efforts and creates air pollution.
“Incineration of blades in the kiln contributes to an inherently unsustainable solution,” said Lawrence Bank, a research engineer at the Georgia Institute of Technology. He said companies should first consider extending permits for wind farms, reusing blades in other turbines, or repurposing them for different uses or recycling.
Burning wind-turbine blades results in an emissions reduction of 27% compared with burying them in landfill and burning coal to make cement, according to an initial study by sustainability consultancy Quantis conducted in 2020. It can also reduce the need for raw materials such as limestone and clay.
“There is no significant difference between the wind blades and other waste that we co-process,” said a spokesperson for Holcim AG, one of the world’s biggest cement makers. “The entire operations do have a positive impact on the environment as otherwise the wind blades would usually end up in landfills.”
For U.S. companies, sending scrapped blades to cement plants currently costs roughly 20% to 30% more than sending them to landfill, according to Ms. Merfeld of GE. Cement makers and waste managers are able to charge for taking old blades, she said, because they are helping to solve a recycling problem. That could change as cement makers come under pressure to decarbonize.
“That equation could flip,” she said. “Instead of them getting paid, they [cement makers] would pay for that material in the future.”
Ms. Merfeld added that GE could eventually use concrete made from blades in the pedestals, towers and foundations of wind farms. Using lower-emissions concrete could give the company an edge in the U.S. market for wind-farm equipment, which has grown more competitive after European wind companies moved in.
“We can actually get paid for more, or more likely win the bid,” she said. “It depends on the customer, some are much more aggressive than others in valuing lower-carbon products, but it’s a trend that’s sweeping the industry.”
Although wind-turbine blades can last longer than 30 years, a U.S. tax credit has spurred companies to upgrade their blades with larger models after 10 years to boost electricity output. The government aid has driven higher waste volumes in the U.S. compared with the European Union, which doesn’t have similar incentives for upgrades, said Chris Howell, senior director of recycling operations for the U.S. at Veolia Environnement SA, which has been running a U.S. turbine-blade disposal service since 2020.
When GE upgrades turbine blades, it pays Veolia to process the old ones before they go to cement makers. After launching its service less than two years ago, Veolia now charges wind-turbine operators and manufacturers to prepare more than 3,000 blades a year in the U.S. for use in cement production.
Veolia says the blades it processes typically weigh 6 to 10 tons. After wind-farm operators take the blades down, Veolia cuts them into large pieces and transports them to a site to be sorted and shredded into a “confetti-like blend,” which it delivers to cement factories.
The business covers the majority of retired blades in the U.S. and is already profitable for Veolia, Mr. Howell said.
Among the cement makers Veolia works with is Italy’s Buzzi Unicem SpA, which through its U.S. subsidiary started using old wind-turbine blades as a replacement for fossil fuels two years ago. It uses processed blades at two out of its eight plants in the country, according to Massimo Toso, head of Buzzi Unicem USA.
Danish wind-turbine maker and wind-farm operator Vestas Wind Systems AS has a similar service for its U.S. customers, and says it handled more than 200 blades last year.
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