Peek Into a Wooden Mast Reveals Wind Power’s Towering Future

(Bloomberg) -- Standing nearly 100 feet tall on the rocky shore of the island Bjorko in southwest Sweden, a white wind tower looks indistinguishable from thousands of similar tubes that help generate clean energy all over the world. But inside is another story.

The interior of the tower is a tableau of creamy white boards, soaring into the air like a hollowed-out tree trunk. It's a total redesign of the classic steel turbine tower from Swedish company Modvion AB, which says it can cut costs for the renewable power industry and dramatically reduce the sector's output of greenhouse gases.

Over their lifetimes, wind turbines drastically reduce global warming-inducing gases compared to power from fossil fuels, but making the machines themselves still leaves a carbon footprint. Steel, the main material in turbines, is made with heavy-polluting fossil fuels and is responsible for emitting about 7% of global greenhouse gases every year, according to the Energy Transitions Commission, a group that includes energy and industry executives who want to decarbonize the economy. 

Using a kind of composite wood made up of many 3 to 4 millimeter-thick layers of Nordic-grown spruce, the tower is covered in a waterproof coating and is as sturdy as steel posts, according to the Modvion, which has received backing from the Swedish Energy Agency. The company erected its first demonstration tower last week, signalling to other wind-power companies that ecologically-friendlier manufacturing is on the horizon. 

“We can make wind power completely carbon neutral,” said Otto Lundman, Modvion's chief executive officer. “Nature gives us this carbon fiber to use for large scale construction.”

Later this year, the Sweden Wind Power Technology Centre will mount a tiny 40-kilowatt turbine on top of the tower to commence testing. Modvion is planning to industrialize production so that it can eventually build towers five times higher, which can generate more power from higher wind speeds. Nordic renewable power producer Rabbalshede Kraft AB plans to buy 10 towers, each 150 meters-tall, Modvion said.  

Using wood could reduce the cost as timber is cheaper to produce than steel, Lundman said. A single full-sized wooden turbine would avoid the 2,000 tons of carbon emissions produced by making a steel analog. That could be appealing to turbine makers such as Vestas Wind Systems A/S and Siemens Gamesa Renewable Energy SA that have pledged to produce net zero emissions in the coming years. Vestas has said it wants to develop biodegradable materials to lower the company's carbon footprint.

The Modvion towers can last for decades and then be repurposed as beams for construction and ultimately recycled, Lundman said.

Beyond the emissions aspect, steel towers present other potential problems. As turbine towers have gotten bigger over the years they've helped drive down the cost of wind energy, but also gotten harder to transport and are increasingly expensive.

“Steel towers will need to adapt if they want to remain the main choice,” said Imogen Brown, a wind analyst at BloombergNEF. 

©2020 Bloomberg L.P.