What is made from the same wood as a Christmas tree, held together by glue and manufactured in a Swedish factory for assembly later?

If that calls to mind flat-pack furniture and meatballs, you're wrong.

If you answered "a wooden wind turbine", you could be a visionary.

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.

Steel limitations

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.

Source - BBC News