Small Scale Wind Power

Small-scale wind power turbines generate up to 20 kilowatts, under ideal conditions. This is enough to power most households in the U.S. Like their big brothers on the wind farms, they only generate power when the wind is blowing.

A small-scale wind turbine looks like an airplane with a huge propeller — and that's because that's what it basically is. Wind pushes the vane (the opposite of what happens with an airplane propeller), which turns the propeller and forces the alternator (generator) to rotate, thereby outputting AC power. Modern units are controlled by microprocessors which optimize the efficiency of the units.

The vane serves to keep the turbine facing into the wind, for the most part. There is some wobbling back and forth, but compared to the cost of using an intelligent processor to rotate the turbine directly into the wind, the vane works very well. (This is the same mechanism an airplane uses to keep the plane oriented directly into its line of flight.)

In large-scale turbines, the rotation speed is held constant by gears and processors, but in small-scale systems the speed of rotation is a direct function of wind speed. This makes the resulting output power vary quite a bit, so special electronic converters are used to translate this varying power into useable, residential power.

The smallest turbines (with 6-foot rotors) sell for around $1,000, not including installation (tower building and raising, plus wiring and so on). They output 400 watts of power at wind speeds of 28 miles per hour (this is a pretty good wind) and can withstand winds up to 110 miles per hour. A turbine with a 15-foot rotor produces 3.2 kilowatts at 28 mile-per-hour winds for around $8,000, including installation materials but not labor. Fifteen feet is big, and the turbine makes a deep swooping noise.

In general, a wind turbine must be mounted at least 30 feet above the ground and at least 200 feet away from obstructions. There's 40 percent more wind at 100 feet than at ground level so the higher the better. This creates a real engineering problem, as raising a small wind turbine is a formidable job: The turbine is heavy enough to kill someone if it falls on them, and if not mounted properly, high winds may cause the unit to come crashing down.

There are two ways to use a wind generator: intertie and stand alone.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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