Why Wind Power?
- Gain energy independence
- Ease demand on the power grid
- Reduce vulnerability to volatile utility prices
- Reduce air pollution from fossil electricity sources
- Augment your photovoltaic solar power system (get power when the sun doesn’t shine!)
How Wind Power Generators Works
Wind is caused by differences in atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the lower pressure area, resulting in winds of various speeds. Wind turbines convert the kinetic energy that is inherent in wind into mechanical power that runs a generator to produce clean, nonpolluting electricity. We can divide wind turbines into two categories – small-scale wind and large-scale wind.
Today’s small-scale turbines are versatile and modular. Their rotors consist of two or three blades that are aerodynamically designed to capture the maximum energy from the wind. The wind turns the blades, which spin a shaft connected to a generator that make electricity. A mainframe supports the rotor, generator, and tail that aligns the rotor into the wind.
Turbines are mounted on towers – typically 80-120 feet high – which place the blades high enough to be exposed to the wind. There are many tower options, but in general the taller the tower, the more power the wind system can produce. The tower also raises the turbine above air turbulence created by objects (buildings, trees, etc.) near ground level. As a rule of thumb, the bottom of the rotor blades should be at least 30 feet above any obstacle within 300 feet of the tower. Towers may be self-supporting, but more commonly use guy wires. Some tower models can be tilted down to facilitate maintenance work.
In addition to the tower and turbine, small wind power systems require:
A foundation – usually made of reinforced concrete;
A wire run, to conduct electricity from the wind generator to the electronics;
A disconnect (or safety) switch, which allows the electrical output to be isolated from the electronics;
A power processing (or conditioning) unit, which makes the turbine power compatible with the utility wind power;
A system energy meter, which records energy production.
If the system is designed to stand alone or operate during a power outage it will need deep-cycle batteries (like the ones used for golf carts) to store power, and a charge controller to keep the batteries from overcharging. A grid-connected system not designed to operate during a power outage does not need batteries.
Large-scale wind turbines are large structures designed to generate as much as 8MW from a single turbine. Today’s large-scale wind turbines are lighter and more efficient than years past. Their rotors can consist of two or three blades with blades as long as 195 feet. Towers reaching as high as 410 supports the hub, rotor, and generator. The taller the tower, the more power the wind system can produce. The tower also raises the turbine above air turbulence created by objects (buildings, trees, etc.) near ground level. As a rule of thumb, the bottom of the rotor blades should be at least 30 feet above any obstacle within 300 feet of the tower. Towers may be self-supporting, but more commonly use guy wires. Some tower models can be tilted down to facilitate maintenance work.
Large-scale wind turbines are typically deployed in areas with large amounts of open space and create a landscape of wind turbines rising to the sky, hence the term Wind farm.