Giving wind farms the bird

Former Soviet weapons scientists have developed wind turbines that are almost silent and have a low impact on bird life, removing critical barriers to the building of wind farms.

Units could also be fitted on top of homes, supplementing existing power supplies.

Around 100 experts in structural design, electronics, aerodynamics and helicopter blades have contributed to the project, which is to be commercially developed with funding from the US Department of the Environment’s Initiatives for Proliferation Prevention (IPP) programme.

The blades, made from a lightweight, extremely durable glass fibre, revolve around the vertical axle, like an eggbeater. The vertical axis blade is essentially a wing, and the design is portable, easy to manufacture and requires little maintenance.

‘The blade speed is around twice the wind speed, which is much less than the tip speed on the conventional propeller design,’ said Richard Halstead, president of US company Empire Magnetics, which is providing the turbines’ alternators. ‘The whole thing is much quieter. A comparison might be a propeller-driven aircraft and a glider.’ The low speed of the blades also means birds can see and avoid them.

Turbine designers have traditionally favoured windmills with blades rotating around a horizontal axis as they are more efficient. However, the Russian design has closed this gap.

The units use a directly-driven large diameter alternator, eliminating the cost, reliability and efficiency problems of gearing and mechanical drives used in horizontal axis designs.

Bearing life can be extended using magnetic levitation, and mounting turbines to structures is less expensive as a tower is not required for blade clearance. A 9m high, 3kW model, and an easily portable 1kW design have been built, and the team is now developing a 100kW turbine for use on commercial wind farms.

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