Small wind turbine system

Wind is a form of solar energy and is a result of the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and the rotation of the earth.  Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity

The wind turbine, which is installed on top of a tall tower, collects wind energy and converts it into electricity. The turbine output is then made electrically compatible with the utility and the output is fed into the household wiring at the breaker panel.

The home is served simultaneously by the wind turbine and the utility. If the wind speed is below 7 mph there will be no output from the wind turbine and all of the needed power is bought from the utility. As the wind speed increases the turbine output increases and the amount of power purchased from the utility is proportionately decreased. When the turbine output is more than the house needs, the extra electricity is sold to the utility. All of this is done automatically. There are no batteries in a modern residential wind system.

The wind turbine typically lowers your utility bill by 50-90%. It is not uncommon for homeowners to have monthly utility bills of $8-$15 for part of the year. In northern parts of the country, where less air conditioning is used, the bills can be very low year round.

What size would I need for my home? Homes typically use 1,000-2,000 kilowatt-hours of electricity per month. Depending upon the average wind speed in the area this will require a wind turbine rated in the range 5-15 kilowatts. Our 10 kW unit, the BWC EXCEL-S, is the best selling residential unit in the U.S. It has a rotor diameter of 23 feet and is typically installed on 80 or 100 foot towers..

 Most small wind turbines manufactured today are horizontal-axis, upwind machines that have two or three blades. These blades are usually made of a composite material, such as fiberglass.

The turbine's frame is the structure onto which the rotor, generator, and tail are attached. The amount of energy a turbine will produce is determined primarily by the diameter of its rotor. The diameter of the rotor defines its "swept area," or the quantity of wind intercepted by the turbine. The tail keeps the turbine facing into the wind.

Modern wind turbines fall into two basic groups: the horizontal-axis variety, and the vertical-axis design, named after its French inventor. Horizontal-axis wind turbines typically either have two or three blades. These three-bladed wind turbines are operated "upwind," with the blades facing into the wind.

Utility-scale turbines range in size from 100 kilowatts to as large as several megawatts. Larger wind turbines are more cost effective and are grouped together into wind farms, which provide bulk power to the electrical grid.

Single small turbines, below 100 kilowatts, are used for homes, telecommunications dishes, or water pumping. Small turbines are sometimes used in connection with diesel generators, batteries, and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.