What is U.S. electricity generation by energy source? In 2012, the United States generated about 4,054 billion kilowatthours of electricity.  About 68% of the electricity generated was from fossil fuel (coal, natural gas, and petroleum), with 37% attributed from coal. Energy sources and percent share of  total electricity generation in 2012 were:  Coal 37% Natural Gas 30% Nuclear 19% Hydropower 7% Other Renewable 5% Biomass 1.42% Geothermal 0.41% Solar 0.11% Wind 3.46% Petroleum 1% Other Gases < 1%

Wind power in the United States is a branch of the energy industry, expanding quickly over the last several years. Construction of new wind power generation capacity in the fourth quarter of 2012 totaled 8,380 megawatts (MW) bringing the cumulative installed capacity to 60,007 MW.[1] This capacity is exceeded only by China.[2] For the 12 months until July 2013, the electricity produced from wind power in the United States amounted to 157.8 terawatt-hours, or 3.91% of all generated electrical energy.[3]

Windmills were first used to grind grain anywhere from 2000 to 4000 years ago in ancient Persia or Babylon;

Wind energy is mechanical energy, the rotating movement of the blades of the windmill produces electricity through a generator. The wind is formed by the heating and cooling effects of the suns rays, the air rotates in high and low pressure which generates wind. Depending  on the type of wind pressure that is generated,whether it is a cool breeze on your face, different capacity of the strength of wind is formed in different parts of the world, this power goes to producing an effective source of untapped energy, for use by us in the form of heating and lighting.

Most of the wind energy produced  for power needs comes from wind farms, great big windmill type contraptions produce electricity because as the wind blows it turns the blades on a shaft, which powers a generator.