One of the biggest drawbacks of wind power is its unpredictability. Sometimes the wind blows; sometimes it doesn't.
Not so 1,000 feet up. There, you get a constant breeze unimpeded by trees, hills, and buildings.
The prototype Magenn Air Rotor System (MARS) is essentially a wind turbine built around a blimp. The electricity generated by the wind travels down a tether to a transformer at a ground station, where it is then transferred to the power grid.
The whole apparatus is designed to weather-vane so that it's always facing the wind. It's stabilized by something called the Magnus effect – the same physical phenomenon that keeps a golf ball aloft if you give it enough backspin.
Here's what it looks like:
(Animation courtesy of Magenn)
Magenn claims that the MARS has many advantages over conventional windmills: The wind blows about twice as strong at 1,000 feet, the Magenn's floating blimps are less expensive per unit of energy, and they can be moved around more easily, allowing them to follow changing wind patterns and to be deployed for disaster relief or to provide power to communities in the developing world that are not connected to a power grid.
The company plans to begin shipping a 10-killowat version of its MARS in 2009 or 2010, which is about 25 feet by 65 feet and 1,200 pounds. They haven't finalized their price yet, but they are shooting for between $30,000 and $50,000 per unit (buyers will end up paying about $10,000 more for the helium, which is not included). Magenn says that you can't hook one up to your house if you live within a city or town boundary, and, if you plan on putting one up in North America, you'll have to get a permit from the FAA.
The company says it is planning on coming out with a backpack version for use by campers, probably in five to ten years.