How Windmill Power Works

Windmills convert wind power into clean electric energy.

Windmill power systems provide electricity to off-grid homes, or back to the utility grid for energy credits. They lessen our reliance on fossil fuels and make good economic sense. Built to convert wind power into clean electric energy, windmills are generally made up of a wind turbine, a tower and a set of components required by the type of system installed.

Wind Turbine

A wind turbine consists of two or three blades and often a tail, attached to a rotor which is attached to a generator, and mounted to a frame. The energy produced by a turbine depends on the size of the rotor and blades, which determine the amount of wind collected and sent to the generator. The tail helps the turbine to face the wind.

The Tower

Wind speed increases with height, and wind turbines are mounted on towers to access this wind, producing more power. The tower also raises the turbine above wind-slowing obstructions like hills, trees and buildings. Small increases in tower heights offer high rates of return in power production.

Balance-of-System Components

The balance-of-system components include energy converters and storage controllers, inverters and/or batteries and a variety of wiring and switches, depending on the type of windmill power system.

Types of Windmill Power Systems

There are three common types of windmill power systems. Battery-based off-grid systems can be installed in areas where a power grid connection is unavailable or if you desire independence from the utility company. Grid-tied wind systems with battery backup offer collected power of your own which you can store in batteries or release to the grid for credit, as well as an unlimited supply of electricity from the utility. Finally, a grid-tied system is attached to the power grid, but does not have batteries. This is the least costly system to set up, but is useless when the grid is down.

How It Works

The wind turbine's rotating blades catch the wind´s energy and moves the rotor shaft. The shaft turns the generator, which produces electricity. This electricity, in alternating current (AC) form, is converted to direct current (DC) to charge batteries or feed a grid-sharing connection.

References

• Union of Concerned Scientists: Clean Energy: How Wind Energy Works
• U.S. Department of Energy: Energy Savers: Small Wind Electric Systems
• Homepower Magazine: Wind Energy Basics

Resources

• The Other Power: Wind Power