Wind power: Wood turbines could make the industry more sustainable

By Madeleine bracelet

The following is an excerpt from our Fix the Planet newsletter, a weekly email about solutions to the climate crisis.

In the UK, onshore wind power has been stuck in a little time warp. In England, only a handful of new onshore wind farms have been built since 2015, when the UK government tightened planning rules governing the technology, stifling new projects. (Decentralized nations have different rules, and Scotland plans to double its onshore wind capacity by the end of the decade.) That means many turbines dotted around the English countryside are at least a decade old and, frankly, look pretty worn-out.

From this perspective, it would be easy to assume that wind power is a slow-moving industry, that turbines installed 25 years ago look the same as turbines rolling off production lines now. But away from the quagmire of English onshore wind, the excitement is on. Startups are coming up with new and better designs for the next generation of wind turbines. And one of the most promising ideas is turning trees into turbines.

problem materials

Traditionally, wind turbines have been made from a mixture of different materials. The towers are generally constructed of steel or concrete, while the blades are usually made of fiberglass-reinforced polyester or epoxy.

The production of steel towers requires a lot of energy, while most blades cannot be recycled and therefore often end up in landfills at the end of their useful lives.

There is also a size problem. Taller turbines can collect wind more efficiently, but the construction costs of steel towers increase with height. Transporting and installing turbines also becomes an expensive headache the bigger the towers get.

That problem has led wind companies to start designing better turbines.

wooden towers

Swedish start-up Modvion has developed a system for building turbine towers using sections of laminated timber.

Wood towers are lighter than steel and can be built in sections to be joined on site. This makes taller, more powerful turbines cheaper and easier to transport, says Erik Dölerud, an engineer at Modvion. “The whole market is going towards tall towers, and the taller the towers, the greater the base advantage of wood,” he says. “So it’s definitely a cost-effective solution for those facilities.”

Additionally, producing a wooden tower instead of a steel one generates 90 percent fewer carbon dioxide emissions, according to Modvion. And when the turbine reaches the end of its useful life, the modular segments of the tower can be reused.

Dölerud says that the wood from the decommissioned towers could be used as load-bearing beams in the construction industry, then made into partitions and then into paper. “That’s basically our vision: to have a cascading material reuse of six or seven steps, over many hundreds of years, so that we get the most benefit from each and every cellulose fiber before we release it back into the atmosphere.” , He says. .

The company already has a 30-meter tower in operation on the Swedish island of Björkö, which was erected in 2020. The pilot project helped the company attract the attention of turbine maker Vestas, which invested in Modvion last year.

Work is now underway on a 100-meter-tall turbine for Varberg Energi, due for completion next year and should pave the way for the commercial deployment of wooden towers. Eventually, the towers could reach heights of up to 150 meters. “The ultimate goal is to be a world leading provider of wind turbine towers by the 2030s,” says Dölerud.

wooden blades

Meanwhile, German startup Voodin Blades envisions wind turbines being built with wooden blades, which are lighter and easier to dispose of than fiberglass blades.

It is building its first 20-meter-long blades, which will be installed on a 0.5-megawatt capacity test turbine in Warburg, Germany, later this year. He is also working on an 80-meter-long blade that could be attached to a turbine of up to 6 megawatts, the size used on commercial farms.

In November, the company announced a partnership with Stora Enso, a Finnish company that makes paper, pulp and other forest products. Stora Enso is supplying its Laminated Veneer Lumber (LVL) to make the blades.

Stora Enso, which also supplies wood to Modvion, claims its LVL is twice as strong as steel on a weight-to-weight basis and can perform as well as fiberglass in a turbine blade. “This is a strong material, a lightweight material, reproducing itself,” says Saki Boukas, who heads Stora Enso’s wood division.

Eventually, the turbines could be made with wooden towers and wooden blades, Dölerud says. “I think it’s a very good idea,” he says. “I think structural lumber should be used for more applications than are currently used. It is a high-end engineering material and should be used for more high-end engineering applications.”

stumbling blocks

So what’s the catch? Perhaps the biggest challenge is convincing risk-averse engineers to take a chance on wood, Boukas says. “In terms of technology, I don’t see any problem. It’s known technology, and all of that is pretty clear. It’s more time and new technology coming into the market, and everyone needs to feel it, touch it, and smell it before they can fully accept it,” he says.

Still, John Hall of the University at Buffalo, New York, thinks the idea of ​​wooden turbines is promising, especially since the huge demand for wind turbines in the coming decades will put the steel industry under severe pressure. . By some predictions, the global wind turbine market is expected to double in value by the end of the decade – steelmaking capacity will have a hard time keeping up.

The industry may naturally be “risk averse,” he says, but that will change quickly if materials become scarce. “Yes [the industry] starts to experience shortages or anything that is going to slow down its growth, I think it will be open to innovation,” he says.