Why do wind turbines have such a relatively low output of electricity?
	
	
		Regarding energy generation:
      If most forms of energy today derive from a rotor spinning and generating electricity from electrical induction, why is it that a single wind turbine, using this same process, has such a lower output of electricity when compared to fossil fuels? There is a wind turbine near my house, and it's pretty much constantly spinning. I have talked to the owners of this wind turbine, and they say it only generates about 5 percent of the power for one industrial building. This, with my somewhat limited knowledge of physics and thermodynamics, boggles my mind. I understand that wind power is much less efficient in harnessing the energy from the wind, and that the wind itself contains much less energy. But if the rotor of a wind turbine is spinning at the same rate as a coal power plant, why is there such a larger output of electricity. Does the speed of the rotor play the biggest factor in the output, or is there something else that I'm missing? 
Thanks