Wing 7 at Makani Power’s test site in Alameda, CA, December 2011. Image copyright: Makani Power, A. Dunlap, 2011.

How High-Altitude Kites Can Reel In Renewable Energy

Kites flying twice as high as the tallest windmills could potentially gather much more electricity than current technologies.

Recently, Google’s research and development arm Google X acquired Makani, a company that makes energy-producing kites.

Flying far above the 200-meter (650-feet) limit of regular windmills, the kites gather energy by flying in a figure-eight pattern at speeds of 70 to 90 km/h (43 to 55 mp/h), according to an article on the website of the renowned Dutch technology university of Delft (UoD).

The high-speed flight of the kite creates a traction force that is converted into electricity by a generator in a power station on the ground that the kite is tethered to.


Photo courtesy of the University of Delft’s KitePower website.

Operating in cycles, the kites generate power while being reeled out to the length of the tether cord, and are then pulled in towards the generator at an angle minimizing the air resistance to avoid spending the energy just created.

The kites themselves are wings made out of inflatable membranes that are lightweight but very sturdy. Steering the kite is done via a small, remote-controlled robot hanging below the wing.

Current prototypes can churn out 20 kilowatts of energy. In comparison, large-scale wind turbines can create 1.5 megawatts to 7.5 megawatts, according to the U.S. Department of Energy (DoE). One megawatt is a thousand kilowatts.


Benjamin Franklin used a kite to prove his theory about electricity

However, proponents of kite power say the amount of potential energy is much higher in the altitudes reached by the kites. to the UoD’s website, the capacity of the kites can be as much as 40 percentage points higher.

And with the cash piles of Google at their backs, and the backing of the DoE’s research department Advanced Research Projects Agency – Energy (ARPA-E) at their backs, the sky seems to be the limit for Makani and kite-powered energy.


Ole Skaar