In the future, might wind power tapped by high-flying kites light up major cities around the world – London, New York, Paris?
Astonishing though it may seem, scientists in the US have been studying exactly this and come up with the view that New York – the “Big Apple” – is a prime location for exploiting high-altitude winds.
They say such winds globally can provide enough energy to meet world demand 100 times over.
Using 28 years of data from the US National Centre for Environmental Prediction and the Department of Energy, Ken Caldeira, of the Carnegie Institution’s Department of Global Ecology, and Cristina Archer, of California State University, Chico, have compiled the first-ever global survey of wind energy available at high altitudes in the atmosphere.
“There is a huge amount of energy available in high-altitude winds,” said Caldeira.
“These winds blow much more strongly and steadily than near-surface winds, but you need to go get up miles to get a big advantage. Ideally, you would like to be up near the jet streams, around 30,000ft.”
Jet streams are meandering belts of fast winds at altitudes of 6,050-9,100m (20,000-50,000ft) that shift seasonally, but otherwise are persistent features in the atmosphere.
The UK feels the impact of such winds quite strongly as they can have a dramatic impact on summer weather. Remember how awful summer 2008 was?
Jet-stream winds are generally steadier and 10 times faster than winds near the ground, making them a potentially vast and dependable source of energy.
Several technological schemes have been proposed to harvest this energy, including tethered, kite-like wind turbines that would be lofted to the altitude of the jet streams. It is claimed that up to 40 megawatts of electricity could be generated by current designs and transmitted to the ground via the tether.
That’s more than half the power used in Britain every day.
“We found the highest wind power densities over Japan and eastern China, the eastern coast of the United States, southern Australia, and north-eastern Africa,” said Archer.
Included in the analysis were assessments of high-altitude wind energy for the world’s five largest cities: Tokyo, New York, Sao Paulo, Seoul and Mexico City.
But Caldeira warned: “While there is enough power in these high-altitude winds to power all of modern civilisation, at any specific location there are still times when the winds do not blow.”
So that means there would have to be lots of back-up power generation. And how would you prevent the kite turbines from crashing?