In the race to harness stronger, steadier winds, wind turbines have moved further out to sea - and now into the sky.
A range of air-borne devices are being developed to turn high altitude breezes into electricity. One design uses free flying kites that can go as high as 800 metres. As the kite is launched and climbs up into the sky, it pulls a rope from a drum on the ground and this motion is used to generate power.
Another system under trial consists of a wing fitted with many small turbines, hundreds of meters up. Wind drives the turbines and electricity is then transmitted down the tether to the ground station and onto the grid.
Whilst it is too soon to say which of these designs will take off, the huge amount of wind power available at high altitudes is certainly a prize worth chasing.
In this earthrise animation we explore the pioneering designs that could shape the way we harness the power of wind in the future.
earthrise can be seen each week at the following times GMT: Tuesday: 2230; Wednesday: 0930; Thursday: 0330; Friday: 1630; Saturday: 2230; Sunday: 0930; Monday: 0330; Tuesday: 1630.
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Source: Al Jazeera