Like the sun, wind is a reliable resource on planet Earth. While it's not always blowing in anyone location, it's always blowing somewhere, and the fact that energy can be stored, transported, or transmitted means that wind power can be very, very useful. There are a number of ways to get power from wind, but most of them involve turning the linear motion of wind into rotary motion of machines.
Most wind turbines use fan-like blades to spin a turbine. This one uses four wings that "flap" in the wind, and generate electricity. This provides a method of wind power generation that could be used in different situations from conventional turbines, and that might avoid some of the dangers to wildlife presented by large, spinning blades.
This turbine uses a helium shell to get up into the atmosphere, held in check by a long tether, and generate power from the constant winds at altitude.