Wind Power – Small Turbine Wind-Powered Generators
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 created by the unequal heating of the Earth’s surface by the sun. Wind turbines convert the kinetic energy in the wind into mechanical power that runs a generator to produce clean, nonpolluting electricity. 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.
Making Home Wind Power Affordable
The US Dept. of Energy has made the use of small wind power generators a major emphasis of its current outreach efforts. DOE’s Advanced Small Wind Turbine Program, combined with industry R&D, is improving small wind power generating technology while lowering the manufacturing costs.
As the market begins to expand, higher volume production is also expected to lower costs, perhaps by as much as 30%. New low-cost “micro” 1.5 kW wind power systems are able to generate 100-300 kWh per month for a total installed cost of under $4000.