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Wind Power Generator

Powering homes is a breeze with wind turbines scaled for personal use.

A small residential wind turbine generates clean power and can even spin utility meters backwards.

Small wind turbines, mounted on towers between 80 and 120 feet tall, can generate electricity from the wind for home use. With on-site installations documented in at least 47 states, wind is a recognized renewable energy source for distributed generation of power on residential home sites. A wind-powered generator, or turbine, situated at the top of a high tower, has blades which spin to generate electricity. The electricity can either be used locally or sold to the utility company if an excess is generated.

In a typical residential application, the power from the wind turbine is connected to the main electric service wire to the home. Special interconnection equipment will allow powering the home, or sending the excess power generated by the turbine back to the utility grid. Otherwise, a distributed wind turbine can be designed as an “off-grid” type using batteries for storage of excess electricity. Many utilities credit the homeowner’s account for power produced by wind turbines that is fed back to the grid and require that special safety features be installed to assure the safety of line workers during power outages.

The amount of power generated by a wind turbine depends on the capacity of the turbine (rated in kilowatts, or kW) and the wind speed. Manufacturers will provide a power curve which shows the turbine’s output (in watts) at given wind speeds. For a typical home that uses 9,400 kilowatt hours (kWh) per year, a unit rated at between 5 and 15 kW will meet most of the home’s electricity needs.

Due to their height, wind turbines are best suited for remote or low-density residential lots of one acre or more. Developments that have adopted restrictive covenants may not allow wind turbines to be erected.

Environmental Performance

By producing power with clean, renewable energy, environmental emissions from power plants are avoided.

Kind of difficult

System installation is an involved process that requires attention to detail. The high first cost can be a deterrent to system installation, but may be offset by government tax incentives that are becoming available for renewable energy installations.

Initial costs can run between $40,000 and $50,000 for a 10-kW system, or a simple payback of approximately 21 years without factoring in tax or other incentives that may be available.

In an area in which utility costs are $0.10 per kWh, the average system will save up to $200 per month if the utility company credits the wind turbine’s excess capacity similarly to the charge for electricity.

Wind turbine towers require a building permit and, possibly, a height restriction variance. Other special code requirements vary by region, so contact the local building department at the outset of a distributed energy installation. FAA regulations will be enforced, if the turbine tower site is close to a municipal airport.

All electrical components and installations must meet requirements of the National Electric Code

Not Applicable

When considering a system, it is important to first check wind resource maps to determine the wind resource in your area. Next, local zoning, building codes, and neighborhood covenants should be reviewed, and any required permits or variances obtained. Supporting technical information can usually be obtained from the manufacturers. The most typical variance needed is for height restrictions—most towers will be between 80 and 100 feet tall.

For a grid-tied system, the local utility needs to be involved with setting up the interconnection. The complexity of this connection depends on the local regulations and the utility’s desire to streamline the process.

Determine where the tower will be placed—it should be at least 160 feet from a house or other structure. A concrete base is poured for the tower and anchoring is provided per manufacturer’s specifications. Light gauge towers require guy wires for stability while others are self-supporting.

To install the system, the tower and turbine are assembled and the turbine is wired and attached to the tower. Next, the tower is raised in place with a crane. After the tower is anchored and grounded, the turbine wiring is run from the tower to the main power service panel. Typically, a trench is dug for the wiring, although lines may be installed overhead. The electrical wiring must be sized to handle the maximum power output of the turbine.

An inverter is required to connect to the utility’s grid.

Warranties vary by manufacturer. Some can be for as long as 5-years for a full warranty on all parts.

Installed, a complete grid-interconnected, 10-kW wind turbine costs between $40,000 and $50,000 and will produce between 800 and 2,000 kWh per month (depending on the wind resource).

As a rule of thumb, wind power systems tend to be cost effective in areas in which the average wind speed is 10 mph or greater and utility costs are more than $0.10 per kWh.

There is some noise associated with the operation of the wind turbine; however, the noise level, described as similar to a washing machine, is not usually objectionable.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.