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I. How Wind Energy Works
Below is an explanation of how electricity is generated by wind turbines put forth by
the U.S. Department of Energy’s Wind & Hydropower Technologies Program.
How Wind Turbines Work
Wind is a form of solar energy. Winds are caused by the uneven heating of the
atmosphere by the sun, the irregularities of the earth's surface, and rotation of the
earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and
vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing,
flying a kite, and even generating electricity.
The terms wind energy, or wind power, describe the process by which the wind is used
to generate mechanical power or electricity. Wind turbines convert the kinetic energy in
the wind into mechanical power. This mechanical power can be used for specific tasks
(such as grinding grain or pumping water) or a generator can convert this mechanical
power into electricity.
So how do wind turbines make electricity? Simply stated, a wind turbine works the
opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines
use wind to make electricity. The wind turns the blades, which spin a shaft, which
connects to a generator and makes electricity.
Types of Wind Turbines
Modern wind turbines fall into two
basic groups: the horizontal-axis
variety, as shown in the photo, and
the vertical-axis design, like the
eggbeater-style Darrieus model,
named after its French inventor.
Horizontal-axis wind turbines
typically either have two or three
blades. These three-bladed wind
turbines are operated "upwind,"
with the blades facing into the wind.
