At may resemble a giant rotary washing line, but it might just help Britain meet its hugely ambitious new wind energy targets. At least that's the claim of the company developing a novel "vertical axis" wind turbine dubbed the Aerogenerator.

The 144-metre high V-shaped structure would be mounted offshore and capable of generating up to 9 megawatts of electricity, roughly three times as much power as a conventional turbine of equivalent size. Switching to such a design could ensure that thousands fewer turbines would be needed in order to meet the government's new wind power target, says Theo Bird, founder of Windpower, the Blyth-based firm behind the new turbine.

As unique as it may sound, the Aerogenerator is in fact just the latest addition to a family of wind turbines that generate power through a rotating vertical shaft as opposed to the horizontal shafts of the more familiar windmill design.

The idea for VAWTs has been blowing around for decades, but despite many advantages the technology has so far attracted little interest. That is about to change, according to Bird. Invented by aeronautical engineer David Sharpe, the Aerogenerator is an adaptation of the egg-whisk-shaped Darrieus wind turbine that solves a number of problems originally posed by the technology.

Not least is the ability to build giant turbines, says Neven Sidor of architectural firm Grimshaws - Windpower's collaborator and the company behind the Eden Project.

A Darrieus turbine becomes unstable above a certain height. The biggest HAWTs are capable of producing 6MW of power and stand just short of 200m tall, but if you try to make them any bigger they start to become less efficient.