Home Wind Generators

Small wind generators, ranging in size from several hundred watts to tens of kilowatts with rotors 25 feet in diameter, can lower a residential customer’s electricity bill and/or provide backup power. Typically, they are found in rural areas with a fairly consistent wind source. Since most of these generators produce varying voltages (in terms of amplitude and frequency), they usually require DC-AC inverters to attain compatibility with conventional appliances.

Three Types of Residential Wind Power Systems

Wind generators can be categorized as one of three types:

• Stand-alone systems operate independent of the electric grid. Since the turbines do not store energy, they can only generate electricity when there is sufficient wind speed. Stand-alone systems require batteries (oftentimes over-sized) to maintain a continuous flow of power. In the absence of another power source, the only option to an over-sized battery bank is to supplement a stand-alone system with a photovoltaic (PV) or an auxiliary engine-generator set (fueled by either a diesel or propane tank).
• Grid-Tied systems, as the name implies, are connected parallel to the utility grid. Wind-generated energy is fed directly into the household wiring which reduces the use of electricity provided by the electric utility. Any surplus energy is sent to the utility grid, but this surplus power does not rise to the level of augmenting the utility grid during power outages.
• Grid-Tied systems with battery backup work similarly to the Grid-Tied systems, except that under normal conditions some of the energy is used to keep storage batteries charged. During power outages the system will disconnect from the utility grid and the home will be powered from the energy stored in the battery bank.

Requirements and Expectations for Installation

The actual turbine (wind turbine) generates power proportional to the wind speed, with maximum output achieved with wind speeds ranging between 24 and 36 mph A minimum average wind speed of 9 mph to support a small wind installation. The toll tower provides the height (should be at least 10 feet plus the blade length above the top of any obstruction within 300 feet) to ensure more wind energy is actually harvested. For home applications, there may also be local zoning rules/laws to consider.

Relative Cost of Residential Wind Generators

$4,500 to $6,000 per kilowatt of capacity (before any credits or rebates) is a current (2010) general rule of thumb for estimating the installed cost of a residential wind energy system, recognizing that the per kilowatt costs decrease as the capacity requirements increase. For a typical small residence, the costs will range between $15,000 and $30,000. These systems are approximately 70 percent the cost of an equivalently sized solar electric system. These installations often make sense in a remote location without easy access to utility lines.

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