Wind turbines have been sprouting up everywhere, mostly on land but also in shallow offshore locations, but the best place to capture wind energy is high up in the sky.
In fact, hundreds of terawatts of power are just waiting to be harvested using novel flying wind turbines. Because the wind velocity increases at rising height above the ground, bigger wind turbines are being built with larger towers and bigger blades, but these take a lot of materials to construct and are very costly. The wind also sometimes does not cooperate and blow, so the wind turbines sit idle.
Building smaller turbines that stay in the higher velocity air stream, means you need smaller turbine blades, using aerodynamic lift to stay aloft while the turbines spin to generate electrical power. The electrical power is then sent back to the ground via a tether and high voltage connection. Being able to take advantage of the higher altitude winds, means there are more places where wind power can be harvested.
Joby Energy and Makini Power are each pursuing their own designs to pluck electrical power from the high velocity winds that blow from 100m (328ft) and upwards. Each company claims that they can capture the wind energy, convert it to electrical power using electrical generators that drive propellers to get their Aerial Wind Turbines (AWT) airborne and then convert them into mini power turbines, once the AWT is flying like a large tethered kite.
Joby Energy hopes to get their 500 kilowatt AWT flying next year. Makini Power hopes to get their 1MW AWT flying, and have a 10kw technology demonstrator proving the concept. Each company has had to develop specialized control systems for their AWTs, lightweight structures, advanced electrical generators, mini-propeller/turbines and high-voltage power-carrying tether systems.
Provided people are cool with having these AWTs flying around, even in remote areas, or offshore locations, then this looks like a promising way to harvest wind power, and perhaps avoid some of the perceived aesthetic problems of large wind turbines.