High-flying researchers target jet stream wind energy

New York City could theoretically be powered entirely by high-altitude wind turbines, according to a new report released by environmental researchers.

The paper, published this week in Energies Open Access Journal, purports to be the first survey of global high-altitude wind patterns. It found that wind speeds at high altitudes of about 30,000 feet can be 10 times greater than speeds on the ground, thanks to the jet stream – a high-powered and relatively regular, reliable source of wind.

The study, produced by Ken Caldeira at the Carnegie Institution's Department of Global Ecology and Cristina Archer at California State University, found particularly high wind speeds over Japan, eastern China, and eastern parts of the US.

Whereas the best locations for wind power on the ground generally offer about 1kW per square metre, the faster, high-altitude winds could offer densities of 10kW per square metre, said Caldiera.

The report said that stringing together tens or even hundreds of lightweight high-altitude turbines could produce significant amounts of energy. However, it warned that even though wind speeds at these altitudes are relatively stable compared to ground-based turbines, high-altitude wind projects would still have to cope with variation in wind patterns.

Nevertheless, several makers of prototype high-altitude wind turbines envisage a kite-like system, tethered to the ground, which uses numerous rotors both to stay aloft and to capture energy from these high-speed winds.

California-based Sky WindPower, which has been testing high-altitude wind turbine prototypes, said power could be transmitted to the ground via the tether. The company calculates that it is theoretically possible to generate electricity from such high-altitude systems for just two cents per kilowatt hour, which would make it cheaper than fossil fuel-based energy production.

Several other firms are also working on prototype high-altitude systems, including Makani Power and Canadian firm Magenn.