Is Wind Electricity Right for You?: Page 3 of 4

Turbine Size

“There’s no replacement for displacement” is a common phrase in the engine world. “Swept area matters” is the analogous statement in small wind circles. The “rotor”—the blades and hub, which sweep a circle measured in square feet—is the collector area. More collector means more wind energy collection. Ignore advertising claims that you can get lots and lots of energy out of a small collector. They’re just not true.

If you don’t have verified production numbers for the turbine, swept area is as good of a comparative measure as we have to guess at wind turbine production. In general, home-scale turbines fall within the 12- to 50-foot-diameter range if your goal is to meet a significant portion of your home’s energy needs.

Maintenance

All wind generators need regular maintenance. A turbine is a dynamic piece of spinning equipment operating in a severe environment. Compare the rpm and lifetime of a wind generator with your car. Let’s assume you drive your car for 200,000 miles at an average speed of 50 mph before trading it in. This equates to 4,000 hours of driving. That’s all! There are 8,760 hours in a year, and your wind turbine is likely spinning and generating energy about 80% of that time, or about 7,000 hours. That’s nearly two car lifetimes in a single year of turbine operation.

Well-designed wind turbines are projected to last 20 to 30 years before a complete rebuild is necessary. No one in their right mind would buy a car and expect to drive it for even 2,000 hours without inspections, service, and maintenance. Why believe otherwise about a wind turbine?

If you don’t change the oil in your car, it will die an early death. If you don’t maintain your wind generator, it will die an early—and probably a very dramatic—death. Turbine owners should stick with a regular schedule to keep up with maintenance.

Most required “maintenance” is centered around thorough inspections of the turbine as well as the tower. This means at least once a year (ideally twice), you need to climb or lower your tower, give it a thorough go-over, and do all necessary maintenance and repair. There’s no shortcut here; no such thing as a “maintenance-free” wind turbine. As the saying goes: “If you don’t pay your turbine a visit at least annually for a preventive maintenance inspection, someday, it may come down and pay you a visit.” If you want a technology that doesn’t require this level of maintenance, buy PV modules—they have no moving parts to maintain.

Do You Pass the Test?

So, how did you do? Ask yourself these questions:

• Do you have the space for a tower, and the type of neighbors who can live with it?
• Can you deal with (or work to change) local permitting or zoning regulations to install a productive system?
• Is there a reasonable wind resource at your site, preferably an average that falls within a 10 to 14 mph range?
• Can you afford to install a tall tower that gets your wind turbine rotor at least 30 feet above all nearby obstructions, including growing trees, for the life of the system?
• Can you afford a durable turbine that will stand up to conditions at your site for decades?
• Can you afford a large enough turbine to significantly offset your energy needs?
• Are you willing to maintain the turbine and tower or pay someone to do this on a regular basis, and are you prepared to deal the inevitable repair?