Go, fly a kite

Wind turbines are getting taller by the day because, the higher you go, the faster and more consistent the winds are. The tallest wind turbine tower today is 178 m — its blade tip reaches up to 246 m — but that’s still not as good as, well, 800 m. But you can’t build a turbine that tall — the economics will throttle it dead.

But people have come up with better ideas. One that is gaining ground in the West has to do with ‘kites’. Companies like Germany’s SkySails and UK’s Kite Power Systems have made some machines and are working on bigger ones.

The idea is pretty cool. A tethered, furled kite is raised by a mast and allowed to unfurl. As it rises with the wind, the cables unwind on a spool that is connected to a generator or a compressor that stores the energy. For technical reasons, the kite is carefully flown in figures of 8. When it reaches its maximum height, it is brought to a ‘least resistance’ position and lowered to ground — which takes just a fraction of the energy it produces on its way up.

Then you start all over again.

The entire system can be packed and transported on a container truck. Or, shipped offshore, where winds are even better. They can be married to standing offshore wind turbines or oil platforms. KPS, which is working on a 50-m-wide kite, 3-MW system, says these can generate electricity for $62.5 a MWhr, compared with $115 for offshore wind power today and $50 by 2030. And the technology is still in its infancy.