Wind energy systems are often classified in two different manners, small wind and large wind. According to the
American Wind Energy Association (AWEA) a small wind turbine is a turbine with a rated capacity below 100 kW. Small wind turbines are sized for homes, farms, and small businesses and are used for numerous applications ranging from powering a small battery bank for back up power, to reducing utility bills, all the way to powering a home or small business without needing to be connected to the electric grid.
In general small wind turbines need to be installed in areas that experience a consistent wind over 8 mph. In the state of Tennessee this often occurs at elevations over 1500 feet along the Cumberland Plateau and in the Appalachian Mountains, although west Tennessee has reported conditions favorable for small wind applications. General siting guidelines for small wind-electric systems can be found on the right in a publication created for the
Tennessee Valley Authority (TVA) by the
National Renewable Energy Laboratory (NREL).
Grid-Connected Wind Energy Systems:
Small wind turbines owners often prefer to remain connected to the electric grid in order to use power from the grid when the wind is not strong enough to meet the required energy demands. To promote the use of distributed power, such as small wind energy applications, the TVA created a program called
TVA Green Power Switch Generation Partners Program that allows customers of participating distributors to sell their power back to TVA for a premium rate of $0.15/kWh produced. This is ideal for customers who want to generate their own power to sell the utility and offset their utility bills. Due to the geographic sensitivity of wind, it is often difficult to project the payback of a wind energy system without the use of an anemometer. However, wind maps can give an individual a general idea of what they might expect at their location. Also, following the siting guide to the right can give you can idea if you have a adequate site for a wind energy system.
Off-Grid Wind Energy Systems
There are often times where it is desirable to not be connected to the electric grid at all. Whether this is because of economics, security, or a personal decision, wind turbines can be a great way to generate enough electricity to ensure a person can power their home. Off-grid systems typically consist of a small wind turbine that charges a batter bank. The battery bank is then used to send the electricity to the load. Because of the additional costs of components, off-grid systems are slightly higher that grid-tied systems. Off-grid systems also work best when paired with other renewable generation technologies such as solar or micro-hydro systems. Together, these are commonly referred to as hybrid systems and help ensure that the battery bank receives a constant supply of energy.
Off-Grid energy systems are often installed for those who no longer want to be subject to increased electricity costs, or what to have a backup source of energy for their home in case of grid failure. Also, in places where the electricity grid does not currently exist, it may be economical to power the house using an off-grid hybrid system. Components of an off-grid small wind energy system include, but are not limited to, the wind turbine(s), tower, inverter, battery bank, and charge controller.
