Given the opportunity to work with some of the brightest minds in the cleantech industry who are creating everything from micro hydroturbines to small, lightweight, three-wheeled electric cars, I’ve learned that bigger is not always better. Yet in the case of a new wind power innovator, their approach has been to go big – in this case, tall – or go home.
Their innovation is made possible by combining ideas from the past with the design technology and capabilities of today.
In Hanover, Germany, a 100-meter wooden tower is rising that – when completed – will be crowned with a 1.5-megawatt wind turbine weighing 100 tons that will produce electricity for about 1000 households. The tower, currently more than 90 percent complete, will be the equivalent of a 30-story building and online by end of year.
The company responsible for this towering achievement is a German cleantech startup called TimberTower, who I briefly mentioned in an earlier post on renewable energy sources. This innovative company, headquartered in Hanover, has made it their mission to develop wooden towers that can be used as the base for wind turbines. (At its simplest, a wind turbine is composed of a tower, a drive train, and rotor blades. TimberTower is strictly focused on the towers, taking a vendor-neutral approach to the other components, “future-proofing” the base as technology advances).
While wood might not seem like the most cutting-edge material, it turns out that if you’re going to build a massive wind turbine tower—the large heights are necessary to increase yields—there are several compelling reasons to create them out of wood.
First of all, wind turbines with conventional steel towers cease to be financially viable at hub heights greater than 85 meters, largely owing to the rising price of steel.
Secondly, since TimberTower uses flat panels of laminated wood to construct its towers, the loads are easily stackable and transportable, in contrast to steel tower segments. The entire TimberTower kit can be transported using standard container vehicles, rather than having to be transported as an abnormally-sized load—a logistically challenging procedure that can be up to 10 times more expensive.
Third, building towers out of wood makes sense for a forest-rich region like Germany, where the raw materials can be easily sourced close to the point of use from woodlands given the stamp of approval by the largest sustainable forest certification system in the world.
Using a timber alternative for a 100-meter tower saves around 300 tons of sheet steel, which requires an enormous amount of energy to produce. And at end of its life, the wooden components that make up the towers can be easily disassembled and reused for construction purposes, or even transformed into wooden pellets (about 180 tons worth) for energy recovery.
Pretty nifty. But perhaps the most interesting aspect of TimberTower’s innovation is the way it borrows an idea from the past and reinvents it for the future: windmills, after all, have used wooden towers as the base for their turbines for centuries.
Just goes to show that cleantech—innovative and futuristic as it is—isn’t always about discarding the old ways of doing things. Sometimes it’s about taking an idea that’s been around for a long time and helping it reach new heights.