Wind Generators and Turbines
Why Use Wind Power?
Solar and wind resources often complement each other. Often when it is sunny, it is calm and when it is cloudy, it is windy. This complimentary effect is even greater during seasonal changes. During the winter when the sun is at its least exposure, the wind is at its highest. A wind generator can be essential during these periods. If you have a system with batteries, the wind can keep your batteries charges and your lights on.
Most Wind generators produce DC so if you have a solar electric system with batteries you can just charge the batteries independently of the solar system. The wind generators will have their own controllers and will regulate their speed according to the needs of the battery.
Most wind generators are designed to put out maximum power at wind speeds of 30 mph. (Wind speeds of only 15 mph will only delivery about one eighth of their rated power.) Wind powered battery charging systems can be cost-effective if the average wind speed is only 9 mph or more. Using wind power in combination with photovoltaic power may be a good alternative if reasonable wind speeds are only available for part of the time.
Other considerations are to mount the wind generator at least 20 feet higher than any obstructions closer than 300 feet. Also, the power output will decrease about 3% for every 1000 feet of elevation. This is because of the thinness of the air.
We do not recommend mounting wind generators on roofs. Though it is possible with a wind generator of 500 watts or less output, it could be noisy. Freestanding towers, guyed towers or guyed poles may be used with a wind generator. Wind generators can be mounted on freestanding towers designed for antennas. They require a large, engineered concrete base for support, but since they do not require guy wires, they can be installed in the smallest space. Guyed steel truss towers, also designed for antenna mounting, are less costly and require a larger area for guy wire placement. A tilt-up pole tower is the most economical and the easiest to install. Wiring and mounting of the wind generator are done before the tower is erected. No climbing is necessary. Steel tubing can be bought locally to save on freight.
To find out average wind speeds in your area, check the U.S. Department of Energy wind maps.
Call for pricing on the Whisper Wind Generator series from Southwest Windpower.
