NETHERLANDS: It has to be the most eye-catching way of harnessing energy. Researchers at the Delft University of Technology, based in the Netherlands, have used kite power to generate enough electricity to supply 10 homes. They believe the system can produce even more energy.

A flying kite tethered to a generator on the ground tugs on its string and generates power, according to Dutch physicist Prof Wubbo Ockels, who heads the "Laddermill" project.

Unlike commercial wind turbines, built generally under 100 metres high, kites can take advantage of stronger and more reliable winds at higher altitudes, climbing to a dizzying 800 metres. When a kite has reached its maximum height, it can be reeled back in to start the process again.

The process could provide electricity at around half the current cost of conventional wind turbine generation, the researchers are estimating. Dutch and British scientists have been working out tricky mathematical models to best harness energy from the kites.

So far, a 10sq m kite has generated 10 kilowatts.

The Delft researchers propose to eventually ramp up the Laddermill model with multiple kites extending nearly 10 kilometres in height, where the wind energy is 20 times higher than at sea level.

They estimate this could generate up to 100 megawatts.