Product Pick of the Week - Wind turbines attached to trees

Wind power is a useful source of clean energy, but it suffers from several shortcomings – not least the fact that the best wind-farm sites tend to be far from the areas that consume the most power.

Setting up conventional windmill-style wind turbines in cities is impractical because they need to orientate themselves towards the wind and so require a relatively large amount of space in which to pivot. One way around this is to use vertical airfoils that can exploit the wind from any direction. But they still need to be mounted in a space of their own.

Now Sridhar Condoor at Saint Louis University in Missouri has designed a hollow, cylindrical wind turbine that has no central hub. Its tube-like form means the device could be placed around a pre-existing feature such as a chimney stack, cellphone mast or even a tree trunk.

The outside of the turbine is a cylinder that is incised with inlets to catch the wind from any direction and toothed on the inside to drive a gear that powers a generator.

A cylindrical frame within allows the main cylinder to rotate freely and can be mounted around another object - either vertically or horizontally. That makes it possible to install without needing clear space, and could even provide a way to hide ugly features, the patent says.