Wind energy is considered as one of the greatest renewable power sources on Earth. On different parts of land wind is produced due to variations in temperature. As light from the sun heats up surfaces, different temperatures of air are produced. Temperature over water surface like lake or ocean will always be cooler than the temperature over rocky ground. Following are some facts about Windmills-

• Wind energy is a renewable energy source and it will exist as long as sunlight exists.
• Man has been using wind as an energy source since he used to sail boats.
• In Iran, initial windmills were used to move wheels to grind grain.
• In America, first windmills were used to grind grain, cut wood and move water.
• In the period of 1920s in rural America wind power harnessed by windmills was a major source of energy.
• California is the biggest user of wind power in modern era, which produces double energy than other states in America.
• In current scenario windmills generally come in two forms, vertical and horizontal models.
• Horizontal windmills are stereotypical version.
• Vertical windmills are rhythmic when they spin but look like egg beaters upside down.
• United States of America generates 17 billion kilowatts wind energy per annum.
• In America more than 30 states have wind farms, which generate and supply electricity to utility companies.
• In America California, Texas, Minnesota and Lowa are dominant forces in wind energy production.
• Germany is biggest wind energy producing nation in the world and Spain ranks second.
• Holland is the leading nation in windmill technology.
• Most of the wind power plants are owned by private companies, which sell energy to utility companies.