Operation and Control of Renewable Energy Systems

Chapter 7Wind Energy

7.1 Wind as Source of Energy

The wind power is basically nothing but another form of solar energy. Approximately 1% of the total solar energy absorbed by the Earth is converted to kinetic energy in the atmosphere, in the form of wind. Since early recorded history, people have realized the potential of wind energy and utilized it for various applications. It was used to propel boats along the Nile River as early as 5000 BC, and it was used to pump water and grind grain between 500 and 900 BC. By the 11th century, windmills were used in food production in the Middle East. The windmills were further improved by the Dutch and others and were adapted for industrial applications such as sawing wood, making paper and draining lakes and marshes. In the late 19th century, the wind power was used in windmills to pump water for farms and ranches. However, due to industrialization and rural electrification, in the 20th century, there was gradual decline in the use of windmills for mechanical applications.

First large-sized automatically operating wind turbine for generation of electricity was built by Charles Brush of the United States in 1888. From 1920 to 1940, propeller-type horizontal-axis wind turbines (HAWTs) with two or three blades were used to supply electricity in rural areas where supply of electricity from the grid was not available. However, the use of wind turbines to generate electricity at a commercial scale started in the 1970s as a result of technical ...