Living off the grid, Part IV: Catching the Wind

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How do you know what your average wind speed is? Although wind speed data are easily accessible for many locations throughout the United States, it might not be accurate for home wind applications. Most of the wind data are collected at airports, which are generally built in places with the least amount of wind. According to Mick, "unless you live in a hole or the middle of the woods, you can expect at least a 1- to 4-mph increase above airport data." If you have any doubts, do a little studying on your own. Anemometers can measure wind speed at any location (and some simple hand-held models can be purchased for as little as $15). They should be positioned as high as the wind system tower will be. To get an estimate of your average wind speed, you can measure your site twice a day for 2 weeks. Then call the local weather bureau and find a ratio between your readings and their daily measurements. You can then extrapolate to estimate your wind site year-round. Once the average wind speed is known, it is a simple matter to determine how much energy is available to you.

But that is only half of the equation. You also need to know how much energy you use. And for a wind system (or any renewable energy system, for that matter) to be practical, it is necessary to use energy efficiently. That means no electric stove, electric water heater, or electric clothes dryer. Solar thermal energy or propane makes more sense for those applications. You can run the majority of your current appliances, but energy-efficient models will be of tremendous assistance in the long run. Reducing your need for electricity will do more than anything else in making your system affordable.

Paying for Power

Once the wind system is up and running, your utility bills will be substantially lower, or even nonexistent. However, energy doesn't come free. Like any other renewable energy device, the cost of the equipment, or the first cost, is what will dig into your wallet. Mark and Ellen's 1-kW system costs about $4,500. A third of the cost was the turbine, a third was the tower and installation, and the last third was miscellaneous hardware. They were lucky in that they had the batteries and inverter already in their PV system.

However, a typical 500 – 600-W system can run about $6,000, an amount nearly equivalent to that of a similar solar stand-alone system. The wind turbine will be between $800 and $1,000; the tower, up to $3,000; the batteries, $800 to $1,600; and the inverter, controller, and wiring, $1,000 to $2,000. A utility-tied system will be even cheaper because it doesn't require batteries.

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