2010

Alta Wind Energy Center

The Alta Wind Energy Center, which opened in 2010 in the Tehachapi-Mojave region of California, is the world’s largest wind farm. It has a planned capacity of 3 gigawatts on 9,000 acres. Hundreds of wind turbines will work together to generate the power.

The aeronautical engineering that goes into wind turbines is impressive. Currently, the largest wind turbine generates 8 megawatts. It does this using three massive blades that are each 262 feet (80 meters) long. To get an idea of the size, the full wingspan (both wings) on a 747 is only 225 feet (68 meters). Each wind turbine’s tower is 460 feet (140 meters) tall.

The three hollow blades are generally made of fiberglass—E-glass fibers in a polyester resin. They attach to a hub, which spins a shaft that drives a generator. There is a sensor package that detects wind direction and then a motor that keeps the blades pointed directly into the wind.

The biggest problem engineers face with an operational wind turbine is self-destruction in high winds. If the blades spin too fast, centrifugal forces can rip the turbine apart. The key to survival is blade angle. A computer looks at wind speed and furls the blades as wind speed increases. There is also a heavy-duty braking system attached to the main shaft that allows the turbine to completely stop. The brake is also helpful during maintenance.

Strong, consistent winds are what engineers look for when siting a wind farm. Offshore locations are popular especially in Europe because ocean winds can be uniform. The plains areas of the United States, for example in Texas, Iowa, and the Dakotas, have uniform winds as well.

As turbines get larger they become more cost-effective, and wind power now costs less than power generated by coal or gas. There is but one fly left in the engineering ointment—the fact that the wind sometimes stops blowing. For decades, engineers have been working on systems to store power. Options include immense chemical batteries, flywheels, or compressed air and pumped water systems. Once engineers get the storage problem definitively solved in a cost-effective way, wind power may become the perfect power source.

SEE ALSO Power Grid (1878), Boeing 747 Jumbo Jet (1968), Bath County Pumped Storage (1985), Ivanpah Solar Electric Generating System (2014).

Wind energy is cleaner and less expensive than power generated by coal and gas.