Sizing Small Wind Turbines
Small wind turbines used in residential applications typically range in size from 400 watts to 20 kilowatts, depending on the amount of electricity you want to generate.
A typical home uses approximately 9400 kilowatt-hours of electricity per year (about 780 kWh per month). Depending on the average wind speed in the area, a wind turbine rated in the range of 5–15 kilowatts would be required to make a significant contribution to this demand. A 1.5-kilowatt wind turbine will meet the needs of a home requiring 300 kilowatt-hours per month in a location with a 14 mile-per-hour (6.26 meters-per-second) annual average wind speed.
To help you determine what size turbine you'll need, first establish an energy budget. Because energy efficiency is usually less expensive than energy production, reducing your home's electricity use will probably be more cost effective and will reduce the size of the wind turbine you need.
Wind turbine manufacturers can help you size your system based on your electricity needs and the specifics of local wind patterns. A manufacturer can provide you with the estimated annual energy output of a turbine as a function of annual average wind speed. The manufacturer can also provide information on the maximum wind speed at which the turbine is designed to operate safely. Most turbines have automatic overspeed-governing systems to keep the rotor from spinning out of control in very high winds.
The height of a wind turbine's tower also affects how much electricity the turbine will generate. A manufacturer should help you determine the tower height you will need.