Single-bladed floating wind turbine. From a Dutch company called Touchwind.
"It's designed around a massive single-piece rotor, sitting on the end of a pole that's draped over a big barrel, with a large floating buoy hanging beneath it."
"This one huge double blade, says Touchwind, should cost around 30% as much to make as the triple-bladed arrangements on traditional turbines. It doesn't require any expensive active blade-pitch control systems, and where most standard turbines need to shut down in wind speeds above 25 or so m/sec (90 km/h / 56 mph), this one is rated for speeds as high as 70 m/sec (252 km/h / 157 mph). Less downtime equals more productive hours and more energy."
The reason for the lack of active blade-pitch control systems is the wind itself and the dangling buoy server to control the angle of the blade, so it always has the right exposure to the wind.
Single-bladed floating wind turbine promises half the cost, more power
