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. View the wind turbine animation to see how a
wind turbine works or take a look inside.
Wind is a form of solar energy and is a result of the uneven heating
of the atmosphere by the sun, the irregularities of the earth's surface,
and the rotation of the earth. Wind flow patterns and speeds vary greatly across the United States
and are modified by bodies of water, vegetation, and differences in
terrain. 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.
Types of Wind Turbines
Modern wind turbines fall into two basic groups: the horizontal-axis
variety, as shown in the photo to the far right, and the vertical-axis
design, like the eggbeater-style Darrieus model pictured to the
immediate right, 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.
Wind turbines can be built on land or offshore in large bodies of
water like oceans and lakes. Though the United States does not currently
have any offshore wind turbines, the Department of Energy is funding efforts that will make this technology available in U.S. waters.
Sizes of Wind Turbines
Utility-scale turbines range in size from 100 kilowatts to as large
as several megawatts. Larger wind turbines are more cost effective and
are grouped together into wind farms, which provide bulk power to the electrical grid. In recent years, there has been an increase in large offshore wind installations in order to harness the huge potential that wind energy offers off the coasts of the U.S.
Single small turbines, below 100 kilowatts, are used for homes,
telecommunications dishes, or water pumping. Small turbines are
sometimes used in connection with diesel generators, batteries, and
photovoltaic systems. These systems are called hybrid wind systems and
are typically used in remote, off-grid locations, where a connection to
the utility grid is not available.
Learn more about what the Wind Program is doing to support the deployment of small and mid-sized turbines for homes, businesses, farms, and community wind projects.
