by Nan C Avery

Created on: August 06, 2010   Last Updated: August 07, 2010

Background:

Wind energy is a renewable source of power. It is the physics of how wind is created, that makes it usable. The sun heats up the earth with radiating heat. Hot air is lighter than cool air. As the ground heats, the hot air rises. This causes atmospheric pressure that pushes the cool air down to the ground to heat and rise. This pattern causes wind. Wind used as an energy source, has to have a system to collect the kinetic energy of the wind. This system of collection can be converted for practical use.

How to harness the energy for electricity generation:

Wind turbines used to generate electricity for residential and businesses, are wind activated. There are two types of turbines. One is the vertical-axis type. It works like an egg beater. It works for small power uses: pumping water and grinding grain. This turbine cannot produce enough energy for electrical purposes. Scientists scrapped experimentation of vertical-axis turbines for electricity. Businesses selling the turbines closed.

The second turbine is a horizontal axis, which has the capabilities of converting wind into electricity. This is the style used today on wind farms. Wind farms are an area for horizontal axis turbines utilization. Utility (electricity) scale turbines are over 300 feet high (100 meters). The tower, made of steel, is what gives the height. The turbine is on the top.

How the horizontal axis turbine works -

*The wind blows through blades (made of fiberglass-reinforced polyester – this makes the blades lightweight and yet strong enough to withstand the force of the wind).

*The blades change the wind's energy into a rotational shaft energy (think of a standard fan).

*The shaft connects to a drive train with a gear box that uses the rotation of the blades to

*Spin magnets in the generator and converts the energy into electricity.

*A protective cover, “nacelle”, houses the shaft, drive train and generator.

The turbine attaches to an electrical grid, which has the electronic and electrical equipment (controls, cables, ground support equipment, and interconnection equipment to control the turbine). This attaches to a power line, which transmits the electrical current.

Measurement of electricity.

Electrical production and consumption measurements are in kilowatt-hours (kWH). A kilowatt-hour means 1,000 watts of electricity produced in one hour. An example would be a 50 watt bulb that burns for 20 hours would equal one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour. Americans average about 10,000 kWH annually.

Electrical output of a wind turbine

It depends on the size of turbine or the power rating, and the speed of the wind. The wind-turbines manufactured currently, have a power rating from 250 watts (enough to charge a battery) to 10-KW, which is equivalent to 15,000 (kWH) yearly (one household), to 1.8 MW, which is enough, to power about or more than 500 households.

Wind-electricity is highly practical. Unlike other forms of alternative energy, such as geothermal, (which has to be drilled), and the unknown environmental consequences, wind energy is readily available.

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