Wind power: Wood turbines could make industry more sustainable

Sections of a wooden wind turbine tower under construction at Modvion’s manufacturing facility

modvion

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

In the UK, the onshore wind is somewhat stuck in a time warp. Only a handful of new onshore wind farms have been built in the UK since 2015, when the UK government tightened the planning rules governing the technology and blocked new projects. (Developed nations have different rules, with Scotland planning to double its onshore wind capacity by the end of the decade.) This means that many turbines scattered across the English countryside are at least a decade old and frankly looking pretty tired.

From this perspective, it would be easy to assume that wind power is a slow-growing industry, meaning that turbines installed 25 years ago look the same as turbines currently rolling off production lines. But far from the English landwind swamp, the excitement is at its peak. Start-ups are developing new and better designs for the next generation of wind turbines. One of the most promising ideas is to turn trees into turbines.

Difficult materials

Traditionally, wind turbines were made from a mixture of different materials. Towers are usually made of steel or concrete, while wings are usually made of epoxy or glass fiber reinforced polyester.

While steel towers are energy-intensive to manufacture, blades are mostly non-recyclable and therefore often end up in landfill at the end of their life.

There’s also the size issue. Longer turbines can collect wind more efficiently, but the construction costs of steel towers increase with height. Transporting and installing turbines becomes an expensive headache as towers grow.

This problem has led wind companies to design better turbines.

wooden towers

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

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

Also, according to Modvion, producing wooden towers instead of steel towers produces 90 percent less carbon dioxide emissions. When the turbine reaches the end of its life, the modular parts taken from the tower can be reused.

Timber from decommissioned towers can be used as load-bearing beams in the construction industry, then made into partition walls and then into paper, Dölerud says. “Basically that’s our vision – to have six or seven steps of gradual reuse of the material over hundreds of years to get the same amount of benefit from each cellulose fiber before returning it to the atmosphere,” he says. .

The firm has and is operating a 30-metre tower built in 2020 on the Swedish island of Björkö. The pilot project helped the company catch the attention of turbine manufacturer Vestas, which invested in Modvion last year.

Work is now underway on a 100-metre turbine for Varberg Energi, which will be completed next year and will pave the way for the commercial launch of wooden towers. Eventually, the towers can reach heights of up to 150 meters. “The ultimate goal is to become the leading global supplier of wind turbine towers by the 2030s,” says Dölerud.

Inside a wooden tower

Inside a wooden tower

modvion

wooden knives

Meanwhile, German start-up Voodin Blades has a vision for wind turbines to be built with wooden blades that are lighter and easier to throw than fiberglass blades.

It is building its first 20-metre-long blades, which will be installed on a 0.5-megawatt test turbine in Warburg, Germany, by the end of the year. Work continues on an 80-meter-long blade that can be attached to a 6-megawatt turbine used in commercial farms.

In November, the company announced a partnership with Stora Enso, a Finnish firm that produces paper, pulp and other forest products. Stora Enso supplies the laminated veneer lumber (LVL) to make the blades.

Stora Enso, which also supplies lumber to Modvion, claims that LVL is twice as strong as steel in proportion to weight and can perform as well as fiberglass in a turbine blade. “It’s a strong, lightweight material that reproduces itself,” says Saki Boukas, who runs Stora Enso’s timber division.

Dölerud says turbines could eventually be made from wooden towers and wooden blades. “I think this is a very good idea,” he says. “I think structural wood should be used for more applications than it currently is. This is a high-end engineering material and should be used for higher-level engineering applications.”

stumbling blocks

So, what’s the problem? Perhaps the biggest challenge, Boukas says, is convincing risk-averse engineers to take a chance on lumber. “I don’t see any problem in terms of technology. It’s a known technology and everything is pretty clear. “More time and new technology needs to hit the market, and everyone needs to feel, touch and smell it to fully accept it.”

Still, John Hall of New York University, Buffalo, thinks the wood turbine idea is promising—especially as the huge demand for wind turbines in the coming years will put the steel industry under serious pressure. By some estimates, the global wind turbine market is expected to double by the end of the decade – steelmaking capacity will struggle to keep up.

He says the industry can be inherently “risk averse,” but that will change quickly if supplies are short-lived. “If [the industry] “I think he’ll be open to innovations if he starts experiencing famines or anything that slows his growth,” he says.

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