Kite Power catches the wind

A traditional childhood pastime could provide a breakthrough in renewable energy, after successful experiments in flying a giant kite at one of Europe’s top research centres. Scientists from Delft University of Technology in the Netherlands harnessed energy from the wind by flying a 10-sq metre kite tethered to a generator, producing 10 kilowatts of power. The experiment generated enough electricity to power 10 family homes, and the researchers have plans to test a 50kW version of their invention, called Laddermill, eventually building up to a proposed version with multiple kites that they claim could generate 100 megawatts, enough for 100,000 homes. Wubbo Ockels, a professor of sustainable engineering and former astronaut who leads the Laddermill project, believes kites are a cheap way to harvest the enormous energy in the wind at a kilometre or more above the ground, where winds carry hundreds of times more energy than on the ground. ‘We need to use all the energy supplies that are offered to us by nature, we need diversity and kites are … intriguing and fascinating,’ he said. Ockels is not alone. Google.org, the philanthropic arm of the Californian web-search company, invested $10m (about £5m) last year in a US kite company called Makani, one of the first awards as part of the organisation’s Renewable Energy Cheaper than Coal programme. The aim of both teams is to tap into high-altitude wind, which is an energy source that is more abundant and reliable than the ground-level wind on which normal turbines depend. Ken Caldeira, a climate scientist at Stanford University’s Carnegie Institution, has estimated that the total energy contained in wind is 100 times the amount needed by everyone on the planet. But most of this energy is at high altitude. The blades of modern commercial windmills sit around 80 metres from the ground, where the wind speed is almost five metres per second. At 800 metres, however, wind speed rises to seven metres per second, potentially generating considerably more energy. It would be virtually impossible to build a standard turbine to take advantage of the wind at 800 metres, but kites could easily get to these heights. Furthermore, thanks to the high-speed jet stream, countries such as the UK, the Netherlands, Ireland and Denmark are particularly suited to flying kites. ‘Pretty much anywhere in the UK you could run a kite plant economically, but you couldn’t run a wind turbine economically,’ said Allister Furey of the University of Sussex, who develops computer control mechanisms to maximise the power generated from kites. A spokesman for the British Wind Energy Association welcomed the idea of devices that could harness the power of jet streams and higher-altitude winds, saying: ‘There is a vast potential that could be harnessed with the technology now available.’

See the full article by Alok Jha in the Observer (3rd August 2008)at

http://www.guardian.co.uk/environment/2008/aug/03/renewableenergy.energy

and see the video at

http://www.guardian.co.uk/environment/video/2008/aug/01/electric.kite