Getting a wind turbine to a decent height to allow it to reach stronger winds than those found closer to the ground generally means sitting them atop a tower. Despite the eco-credentials of wind turbines, these towers are usually constructed from steel, which is not only expensive, but requires large amounts of energy to process. In an effort to make wind turbines even greener, German company TimberTower has erected a wooden 1.5-MW wind turbine in Hannover, Germany.
The TimberTower starts as a linked system of glued laminated timber panels and surface components that are manufactured off-site and transported in 12 m (40 ft) containers for on-site assembly into a hollow octagonal tower. The finished prototype tower measures 100 m (328 ft) high, integrates a ladder and lift system, and is topped off with a Vensys 77 wind turbine. The turbine has a rotor diameter of 77 m (252.6 ft), weighs almost 100 tons (91 tonnes) and generates 1,500 kW of electricity.
TimberTower says the mass and diameter of the tower’s base is identical to that of a tubular steel tower and that all raw materials used in the tower come from FSC and PEFC certified suppliers. In addition to an octagonal cross section, the hollow body can also be constructed with a hexagonal or dodecagonal cross section. The company says the TimberTower system should support hub heights of up to 200 m (656 ft) and is currently in the process of developing a 140 m (459 ft) tower.
With a guaranteed minimum life span of 20 years, the TimberTower also meets current insurability, certification and fire protection regulations. The company claims one 100 m TimberTower saves about 300 tons (272 tonnes) of sheet steel and, thanks to a treatment process that consumes less energy, approximately 400 tons (363 tonnes) of CO2. And after it reaches the end of its working life, the wooden tower can be easily recycled.
With ground broken on the Hannover site in January, the prototype TimberTower was completed earlier this month. It is currently undergoing testing, but should be connected to the power grid by the end of the year.