By Michael Graham Richard, Treehugger

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Internet giant Google has always been a strange company with a finger in many pies. Renewable energy is one of those, and so far it has make huge investments in wind and solar power. So it’s not too surprising to learn that it has just bought Makani Power, a startup working on airborne kite-like wind turbines. Google was already an investor in Makani ($10 million in 2006, $5 million in 2008), but apparently owning just part of it wasn’t enough anymore (Makani will become part of Google X research facility).

I thought this acquisition would be a good opportunity to have a closer look at what Makani Power is trying to do with its innovative airborne wind turbines. Because they have some nice photos available, I’ve used the large image format.
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It looks kind of like a plane, doesn’t it? Why is that? Makani answers:

“Makani uses on-wing generation for enhanced control, safety, operability in a wider range of conditions and simplified launching and landing. The rotors on the wing can be used either as propellers to generate thrust or as turbines to generate energy. This enables the [airborne wind turbine] to remain in the air (consuming a small amount of power) when wind speed is low and enables autonomous launching and landing. On-demand thrust also provides additional control in turbulent conditions where the wind speed and direction may change drastically.”

The video above was taken earlier this month and it shows a test flight, the first ever fully autonomous flight of a kite power system.
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How can it compete with tradition wind turbines? Makani’s answer:

“The [airbone wind turbine] (AWT) performs better at low wind speeds than traditional wind turbines, and because low wind speeds occur more often, the system operates at its rated power more consistently than a conventional wind turbine. Improved low wind performance enables the AWT to produce about twice the power of a traditional wind turbine of the same size.”
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But what happens if the weather turns violent, or if there’s no wind at all?

“Makani AWTs are capable of operating in still air. However, when the wind is below 3 m/s (6.7 mph), the AWT consumes a small amount of power supplied by the tether. During extended periods of low wind the system can land, relaunching itself autonomously when the wind conditions improve. The Makani system is equipped with standby battery power in the event that a drop in wind speed coincides with a transmission grid failure.

The Makani AWT has been shown in simulation to operate in hurricane conditions: winds in excess of 50 m/s (111.8 mph) with gusts reaching 80 m/s (179.0 mph). During particularly extreme weather the AWT can land until conditions normalize.”

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What about airplanes? Are these dangerous for other flying vehicles?

“The Makani Airborne Wind Turbine flies no higher than 600 meters (1,950 feet) above ground level, well below normal commercial and civilian aviation. This is a similar altitude to radio towers and other permanent obstructions. Makani’s AWT will incorporate the lighting and radio beacons typical of airborne devices. Makani’s test sites are awarded NOTAMs (Notice to Airmen) from the FAA.”
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Congrats to the Makani Power team! Hopefully being swallowed up by this whale will help them create world-changing clean energy technology even faster!