|
Wind Energy
|
|
Basic information on
wind energy and wind power technology, resources, and issues of concern.
Wind Energy
and Wind Power:
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 vegetative cover. This wind flow, or motion energy,
when "harvested" by modern wind turbines, can be used to generate electricity.
How Wind Power Is
Generated: 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 to power homes, businesses, schools, and the like.
Wind Turbines:
Wind turbines, like aircraft propeller blades,
turn in the moving air and power an electric generator that supplies an electric
current. Simply stated, a wind turbine is 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.
Wind Turbine Types: Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Durries model, named after its French inventor. Most large modern wind turbines are horizontal-axis turbines.
Turbine Components:
Horizontal turbine components include:
Turbine Configurations: Wind turbines are often grouped together into a single wind power plant, also known as a wind farm, and generate bulk electrical power. Electricity from these turbines is fed into a utility grid and distributed to customers, just as with conventional power plants.
Wind Turbine Size and Power
Ratings:
Wind turbines are available in a variety of
sizes, and therefore power ratings. The largest machine has blades that span more
than the length of a football field, stands 20 building stories high, and produces
enough electricity to power 1,400 homes. A small home-sized wind machine has rotors
between 8 and 25 feet in diameter and stands upwards of 30 feet and can supply the
power needs of an all-electric home or small business. Utility-scale turbines range
in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are
used for homes, telecommunications dishes, or water pumping.
Advantages
and Disadvantages of Wind-Generated Electricity:
A Renewable Non-Polluting Resource:
Wind energy is a free, renewable resource, so
no matter how much is used today, there will still be the same supply in the future.
Wind energy is also a source of clean, non-polluting, electricity. Unlike conventional
power plants, wind plants emit no air pollutants or greenhouse gases
Cost Issues:
Even though the cost of wind power has decreased
dramatically in the past 10 years, the technology requires a higher initial investment
than fossil-fueled generators. Roughly 80% of the cost is the machinery, with the
balance being site preparation and installation. If wind generating systems are
compared with fossil-fueled systems on a "life-cycle" cost basis (counting fuel
and operating expenses for the life of the generator), however, wind costs are much
more competitive with other generating technologies because there is no fuel to
purchase and minimal operating expenses.
Environmental Concerns:
Although wind power plants have relatively little
impact on the environment compared to fossil fuel power plants, there is some concern
over the noise produced by the rotor blades, aesthetic (visual) impacts, and birds
and bats having been killed (avian/bat mortality) by flying into the rotors. Most
of these problems have been resolved or greatly reduced through technological development
or by properly sitting wind plants.
Supply and Transport Issues: The major challenge to using wind as a source of power is that it is intermittent and does not always blow when electricity is needed. Wind cannot be stored (although wind-generated electricity can be stored, if batteries are used), and not all winds can be harnessed to meet the timing of electricity demands. Further, good wind sites are often located in remote locations far from areas of electric power demand (such as cities). Finally, wind resource development may compete with other uses for the land, and those alternative uses may be more highly valued than electricity generation. However, wind turbines can be located on land that is also used for grazing or even farming.
For More Information
Deanship of Scientific Research
Power Electronic and Signal Processing Research Unit (PESPRU)
Dr. Sameer Khader ( Unit Director )
|