World's Tallest Wooden Wind Turbine Starts Turning

An anonymous reader quotes a report from the BBC: According to Modvion, the Swedish start-up that has just built the world's tallest wooden turbine tower, using wood for wind power is the future. 'It's got great potential,' Otto Lundman, the company's chief executive, says as we gaze upwards at the firm's brand new turbine, a short drive outside Gothenburg. It's 150m (492ft) to the tip of the highest blade and we are the first journalists to be invited to have a look inside. The 2 megawatt generator on top has just started supplying electricity to the Swedish grid, providing power for about 400 homes. The dream of Lundman and Modvion is to take the wood and wind much higher. On the horizon near the Modvion project, several very similar-looking turbines are turning. Steel, not wood, is the key material for them, as it is for almost all of the world's turbine towers. Strong and durable, steel has enabled huge turbines and wind farms to be constructed on land and at sea. But steel is not without its limitations, particularly for projects on land. As demand has grown for taller turbines that harvest stronger winds with larger generators, the diameter of the cylindrical steel towers to support them has had to grow too. In a world of road tunnels, bridges and roundabouts, many in the wind industry say getting those huge pieces of metal to turbine sites has become a real headache, in effect limiting how tall new steel turbines can be.

From the outside, there is little obvious difference between the Modvion wooden turbine and its steel cousins. Both have a thick white coating to protect them from the elements and blades made primarily from fiberglass attached to a generator, which produces electricity when it turns. It is only when we go inside the tower that the differences becomes clear. The walls have a curved raw wood finish, not unlike a sauna. The 105m (345ft) tower's strength comes from the 144 layers of laminated veneer lumber (LVL) that make its thick walls. By varying the grain of each of the 3mm-thick layers of spruce, Modvion says it has been able to control the wall's strength and flexibility. 'It's our secret recipe,' says company co-founder -- and former architect and boat builder -- David Olivegren, with a smile. Lundman and Olivegren tell me their turbine's big selling point is that, by using wood and glue, towers can be built in smaller, more easily transported modules. That will make it much easier to build really tall towers, they say, and to take the pieces to challenging locations.

However, Dr Maximilian Schnippering, head of sustainability at Siemens Gamesa -- one of the worlds largest turbine manufacturers -- says more pieces are likely to mean more trucks, more people and more time to complete the installation. He considers the modular system 'an advantage' and that wooden towers can 'nicely complement' steel towers. Though wind power is cheaper and cleaner than almost all other forms of electricity generation, making steel involves extremely hot furnaces and almost always the burning of fossil fuels. That means CO2 emissions -- the main driver of climate change. Modvion says using wood instead of steel eliminates the wind turbines' carbon footprint entirely, making them carbon negative. That's because the trees take carbon dioxide out of the atmosphere when they are alive and, when they are chopped down, the carbon is stored in the wood. As long as the wood doesn't end up rotting or being burned, the carbon is not released. About 200 trees went into Modvion's turbine tower. They were the same species -- spruce -- that is used for Christmas trees and the company says they are farmed sustainably, meaning when they are harvested more are planted. Modvion hopes to build another even taller turbine soon with plans to open a facility that will produce 100 wooden modular turbines a year in 2027. 'The industry is currently putting up 20,000 turbines a year,' Lundman says. 'Our ambition is that in 10 years time 10% of those turbines -- about 2,000 -- will be wooden.'

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