This week the Energy Department’s program for long-shot technologies, ARPA-E, is hosting a convention in Washington where teams of inventors can display their ideas to potential investors and government officials. The technologies are not currently market ready, merely prototype ideas hoping to intrigue the right person and receive funding for more research.
One of the most interesting prototypes shown was a flying wind turbine being developed by Makani Power of Alameda, California. The machine resembles a wing made from black carbon fibre and consisting of four propellers, a thin fuselage and a small with rudder and elevator; just like a small plane, except that it is tethered to the ground and flies in large circles. The device flies at 100 miles an hour, meaning that the relevant wind speed is much higher than the true wind speed, so its turbines generate electricity in winds too gentle for normal stationary wind turbines. It was awarded a $3 million grant from ARPA-E.
The machine can take off from the ground by using power from the grid. Its turbines are used as propellers to give it the lift and get it into its circular trajectory. Then the power is turned off and it draws energy from the wind to continue its path. Each turbine creates about 7.5 kilowatts which flows along its tethering cable back to earth. The large circle that it flies is roughly 165 feet in diameter, about the same size path that the tips of conventional turbine travel.
Corwin Hardham, CEO of Makani, said that the wind turbines would probably be best suited for the ocean where there is more consistent wind, and it can be easily anchored with a buoy, so it will not need an expensive tower to be secured to the sea floor.
By. James Burgess of Oilprice.com