Getting Wind Farms Off the Ground

[The Economist] If it ever seems windy where you live, be thankful that you do not live ten kilometres (six miles) up in the air. At that height the jet-stream winds are stronger and blow more consistently than ground-level winds, and they carry up to a hundred times more energy. … One of the most ambitious ideas has been developed by Sky WindPower, a company based in San Diego and led by Dave Shepard.