Revolutionary new wind turbines spark a surge in renewable energy

New designs turn turbines on their head – literally…

A wave of new turbine designs is brightening the prospects for small- and medium-scale wind power. After years of scepticism over rooftop turbines which cost far more than they will ever repay, there’s the prospect that some of the major obstacles to effective wind power could finally be overcome.

At the crest of the wave is the vertical axis wind turbine (VAWT). While there are now many different versions, the basic idea is that the wind’s energy is used to blow a turbine’s blades about a central vertical axis – much like a child’s roundabout – as opposed to the more traditional horizontal design.

One of the advantages of this is that the turbine can accept wind from any point on the compass without the need to yaw, or change direction, says Stephen Crosher, Commercial Director of London-based developers, QuietRevolution. His company makes a three-bladed helical turbine that is particularly suited to urban environments, both because it is quiet and can cope with low wind speeds. And since the generator and gear boxes are located at ground level, unlike horizontal turbines, maintenance is much easier – making the whole plant more reliable. Buying and installing this turbine would cost up to £40,000, with a payback period of 20 years.

Reliability is key to an ambitious deal struck by US-based Helix Wind to supply power via its bizarre conch-like VAWT to cell phone towers in West Africa. If successful, it could see wind replace diesel as the power source of choice to keep crucial communications running in developing countries.

Vertical axis turbines are not in fact that new an idea, says Crosher. But the drive to get windpower working in urban areas, where horizontal axis turbines traditionally struggle to cope with the turbulence, has led to a resurgence of interest. It’s been made more viable by “the availability of modern composite materials and manufacturing processes”, he says. Together, these have spawned a new generation of designs, like QuietRevolution’s, which suffer reduced vibration, wear and fatigue, and so are quieter too.

Beyond the VAWT is the somewhat more bizarre concept of the flapping wind turbine, currently being developed by Californian start-up Green Wavelength. Inspired by bumblebees, its xBEE turbine consists of two 5.7 metre long wings which swoop in a backwards and forwards pattern in response to the pressure of the wind passing over them. The company says it is now aiming to produce small 10kW models for home and small business use.

But if you really can’t envisage having a giant bumblebee mounted on your home, then perhaps a Ridgeblade is more up your street. Developed by UK-based The Power Collective, this innovative wind turbine resembles a long water mill, and is designed to sit along the ridge of a roof, where it can collect and focus prevailing wind through the device. The first commercial versions are expected to hit the market in 2010. If they prove to be as quiet and efficient as promised, their unobtrusive design could be just what is needed to take wind power into the heart of the city. – Duncan Graham-Rowe

11 January 2010

Duncan Graham-Rowe