Variety of windmills available for home use

Dear Jim: It seems like the area where I live is fairly windy. I have always liked the idea of generating my own electricity with a small windmill. What types of systems are available for home use? – Pete O.

Dear Pete: There is a huge array of windmill sizes ranging from tiny, portable, 13-pound models to large ones that can satisfy the electricity needs of an entire house. If your windmill produces more power than you are using at that instant, many utility companies will buy the extra electricity from you.

The payback you get from installing a windmill depends on the average wind speed in your area and your local electric rates. In many cases, the payback period is long. The reasons for installing a windmill often are for a backup power source or a desire to protect the environment.

An excellent use for tiny, lightweight ones is to keep emergency batteries charged or to provide electricity for cabins, outdoor workshops, boats and RVs. The electricity output ranges from about 150 to 500 watts, easily enough power to keep a wood pellet stove operating during a power outage.

For any of the above applications, a combination of a small windmill and a solar panel is effective. When it is sunny and calm, the solar panels make electricity. When it is cloudy and stormy, the windmill carries the load.

A large whole-house windmill often produces 8,000 to 12,000 watts of electricity and has a blade diameter of 20 feet or more. Some designs begin producing electricity at a wind speed as low as 8 mph, but an average speed of 10 to 11 mph is typically needed to make one more economically feasible.

Even if you install a large, whole-house-sized windmill, you should still keep your house attached to the utility company’s wires (power grid). Sophisticated electronics inside the windmill controller match the electricity output to that of the utility company so they are compatible.

There are typically two ways the electric utility company will compensate you for excess electricity your windmill produces. Under “net billing,” your electric meter just runs in reverse. Another common method uses a second electric meter and the utility company pays you for the extra power.

In addition to charging batteries, another method of storing the wind’s energy is to wire the windmill directly to a heating element in a large water heater tank. The electricity from the windmill keeps the water hot.

The high, very large windmills require a substantial structure for support, but the small models are easy to install. A 1.5-inch-diameter steel pipe is adequate support. The windmill should be about 10 feet higher than any nearby obstructions.