Small wind turbines, mounted on towers between 80 and 120 feet tall, can generate electricity from the wind for commercial & residential use. With on-site installations documented in at least 47 states, wind is a recognized renewable energy source for electric generation of power. A wind-powered generator, or turbine, situated at the top of a high tower, has blades, which spin to generate electricity. The electricity can be interconnected into your load center and used on site or sold to the utility company if excess power is generated. Many utilities credit the homeowner’s account for power produced by wind turbines that is fed back to the grid.  Utility companies do require that special safety features be installed to assure the safety of line workers during power outages.

In a typical residential application, the power from the wind turbine is back-fed into the main electric service panel for the home. Special interconnection equipment will provide power to the home, or send 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.  This application works well for houseboats, vacation homes, and agricultural requirements located in areas where utilities are unavailable or too costly to connect.  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 10,800-kilowatt hours (kWh) per year, a unit rated at between 5 and 15 kW will meet most of the home’s electricity needs depending on the wind resource.

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. APG SOLAR can verify any restrictions, obtain required permitting, compile and submit documentation for available rebates, install your wind generation system, & complete interconnection requirements if net metering.

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 occasionally a height restriction variance. Other special code requirements vary by region.  FAA regulations will be enforced if the turbine tower site is in close proximity to a municipal airport. APG SOLAR will work with the applicable agencies and satisfy any requirements.

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

When considering a wind generation system, it is important to first check wind resource maps to determine the wind resource in your area. Maps can be studied at the following web sites; (CEC) California Energy Commission & NREL ( National Renewable Energy Laboratory) 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 must 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. Currently, PG&E, SCE, & SDG&E have net metering programs administered by the CEC under the CSI (California Solar Initiative).

Determine where the tower will be placed—it should be at least 200 feet from a house or other structure in order to maximize available wind resource.  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 change the DC output from the wind generator to AC in order 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 typically costs between $40,000 and $60,000 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 usually not objectionable. Electrical signal disturbances are nonexistent since modern wind machine blades are constructed of fiberglass or wood. Both of these materials are transparent to electromagnetic signals supplying radio & television.