Frequently Asked Questions

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Wind Energy FAQ

What do wind turbines look like?
There are two basic types of wind turbines: vertical axis or "egg beater" style and horizontal axis. Horizontal axis wind turbines are by far the most common, representing more than 95 percent of all utility-scale turbines (i.e., capacity of 100 or more kilowatts). From the top of the swept area to the ground, a large, commercial horizontal-axis wind turbine can be taller than a 20-story building.

Why do some wind turbines spin, while others next to them do not?
Continuous variations in wind direction, speed and intensity cause some turbines to spin while others nearby may be idle.

How reliable is wind energy?
Sophisticated monitoring and wind resource analysis allow wind developers to estimate with a high degree of certainty "when" and "how much" wind energy is available, so customers can plan their wind power purchases. When the wind blows, it can displace fossil-fueled generation such as oil and gas. Studies have shown that when a utility diversifies its power portfolio with the addition of wind energy, it can meet demands more reliably.

What happens when the wind doesn't blow?
When the wind is calm, the turbine is at rest. However, at the hub height of a utility-scale wind turbine – usually more than 200 feet above ground – on a site selected specifically for its good wind resources, it is rare for the wind to be totally still.

Are there wind seasons?
Yes, but they vary by region. In California, the peak wind season is summer; in the Midwest, it's fall and winter, and in Texas, spring is peak. Each wind plant has specific daily and seasonal variations. Each wind site also has specific wind patterns, which are determined through wind studies conducted during early development of a project.

Do wind turbines operate in extreme temperatures/weather conditions?
Turbines sited in areas that experience extreme cold or heat are equipped with special Arctic or tropical equipment packages. Nevertheless, in sustained winds of 56 mph or gusts of about 100 mph, turbines automatically shut down.

How often do turbines require maintenance?
Wind turbines generally require preventative maintenance checkups two to three times per year.

What does the computer system inside a wind turbine do?
The elaborate computer system inside a turbine performs thorough self-diagnostic tests and troubleshoots errors before the start-up command is given. If the computer detects any problems it cannot auto-correct, the turbine automatically shuts down. In addition, a SCADA (system control and data acquisition) control system allows a remote operator – using a modem from anywhere in the country – to set new operating parameters, perform system checks and ensure turbines are operating at peak performance.

Is wind energy just the latest energy fad?
Not at all. Today, wind energy is the fastest-growing renewable energy resource in the world. Wind energy has always been clean and renewable and, over the past 20 years, the cost of wind energy has dropped about 80 percent. With the federal production tax credit, wind energy can be competitive with other energy sources.