Small Wind Electric System Tower

Renewable Energy Systems

Small Wind Electric System Towers

Because wind speeds increase with height, a small wind turbine is mounted on a tower. In general, the higher the tower, the more power the wind system can produce. The tower also raises the turbine above the air turbulence that can exist close to the ground because of obstructions such as hills, buildings, and trees.

Tower Height

Relatively small investments in increased tower height can yield very high rates of return in power production. For instance, to raise a 10-kilowatt generator from a 60-foot tower height to a 100-foot tower involves a 10% increase in overall system cost, but it can produce 25% more power.

Types of Towers

There are two basic types of towers: self-supporting (free-standing) and guyed. There are also tilt-down versions of guyed towers.

Most home wind power systems use a guyed tower, which are the least expensive. Guyed towers can consist of these components:

Lattice sections
Pipe
Tubing, depending on the design
Supporting guy wires.

Guyed towers are easier to install than self-supporting towers. However, because the guy radius must be one-half to three-quarters of the tower height, guyed towers require enough space to accommodate them.

While tilt-down towers are more expensive, they offer the consumer an easy way to perform maintenance on smaller light-weight turbines, usually 10 kilowatt or less. Tilt-down towers can also be lowered to the ground during hazardous weather such as hurricanes or high winds. Aluminum towers should be avoided as they are prone to metal fatigue and are prone to cracking.

Installation or Mounting

A general rule of thumb is to install a small wind turbine on a tower with the bottom of the rotor blades at least 30 feet (9 meters) above any obstacle that is within 300 feet (90 meters) of the tower.

Mounting small wind turbines on rooftops is not recommended. All wind turbines vibrate and transmit the vibration to the structure on which they are mounted. This vibration can lead to noise and structural problems with the building, and mounting on the rooftop can expose the turbine to excessive turbulence that can shorten its life.