Wind energy kites

Google's latest venture in the field of renewable energy is a flying wind turbine or an ‘energy kite’. The project is being run by Makani Power, a US-based wind energy company which Google acquired last year

 
By Kanchan Kumar Agrawal
Last Updated: Monday 17 August 2015

The wind energy kite (Photo courtesy: Makani Power)

Clean energy is more commercially available than ever, but it still occupies less than 5 per cent of global energy production. The affordability of wind power is limited by existing systems.

Conventional wind power systems are reaching the limits of their technology. To generate more wind power, turbine structures have become taller and heavier. On average, onshore turbines require 100 tonnes of steel, fiberglass, concrete and other materials to produce a single megawatt of capacity.

Makani hopes to enable the shift to clean, renewable energy by building a kite that generates power at a cost lower than any other technology.

This energy kite eliminates 90 per cent of the material used in conventional wind systems. The energy kite generates power through a tethered airfoil that flies in large circles at an altitude of up to 300 metres, where the wind is stronger and more consistent than the winds reached by conventional systems.

Energy kites access more wind at lower cost
 
The ‘flying kite’ will extract more energy at greater heights (Photo courtesy: Makani Power)
 
These kites are tethered to the base station through wires. Without a tower holding them in place, energy kites eliminate 90 per cent of the material and 50 per cent of the installed cost of conventional wind turbines. At the same time, the tether allows the kite to access better wind at higher altitudes, which makes it cheaper to install in places where traditional turbines don't work. This more than doubles the amount of land available for wind energy production.



 

How it works
 
A wind energy kite prototype in the air (Photo courtesy: Makani Power)
 
An energy kite operates on the same principles as a conventional wind turbine, but is tethered to the ground like a kite. The energy kite flies in vertical loops controlled with a computer. The kite mimics the tip of a conventional blade.

Building only the tip of the blade lowers the cost and improves energy production. The kite captures energy at the blade tips through small turbine/generator pairs mounted on a kite. The energy travels down the tether to the grid.

Google hopes to start a pilot project to test the energy kite on a plot of land on the Big Island of Hawaii.

A prototype of the energy kite has been built. You can watch the video here.

Technology roadmap: wind energy

World wind energy report 2012

India wind energy outlook 2012

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