By Paul Wesslund

    Wind energy is big and getting bigger, in more ways than one.
    In the U.S., wind currently generates twice the amount of electricity it did five years ago and provides 10% of the nation’s electricity—a share expected to grow to more than 25% by 2050.
    The basics behind wind power technology is a tall pole with rotor blades at the top. If you’ve taken a road trip across the Midwest, you’ve likely seen huge fields of those turbines, with white rotor blades spinning lazily around. But they’re actually not lazy at all, and that’s another way wind energy is big—in physical size.

Bigger turbines make more electricity
    Wind turbine blades seem to circle slowly due to an optical illusion resulting from how big they are. The tips of those rotors are likely to be moving at more than 150 miles per hour.
    There’s a reason for that size. Wind turbines are getting bigger and taller to capture more wind high in the air. The average wind turbine height has increased from about 190 feet in 2000 to nearly 300 feet today—as tall as the Statue of Liberty. During that time, the size of the rotor blades has doubled, making a circle more than 400 feet in diameter. That size growth has tripled the amount of electricity a wind turbine can produce, lowering the cost of wind power.
    One wind turbine can generate enough electricity to power about 900 homes, and they’re being installed at a rate of about 3,000 a year. Today, there are more than 72,000 turbines in the U.S., primarily located in the middle part of the country. But that’s about to change.
    Federal and state governments are encouraging developers to build wind turbines out in the ocean, where winds are more constant and the rotors could be even larger. Sixteen projects have been proposed and one estimate shows there’s enough potential for offshore wind to supply nearly all our electricity. Offshore wind turbines are generally even larger than those used on land.

Protecting birds from wind turbines
    Bigger sizes can cause problems though, like transporting rotor blades that average more than 100 feet long. Delivering those monsters can cost more than $30,000 in finding the right truck for the oversized load, planning the route, obtaining permits, checking clearances and recruiting escort vehicles. Researchers are already working on those problems. One solution is flexible blades that could be carried on three train cars. The blades could bend to allow the train to maneuver around curves.
    As the wind industry has evolved, attention has been focused on bird deaths—as many as a million birds a year fly into spinning rotors. This poses a dilemma for wildlife and nature groups, who are generally supportive of renewable energy. The National Audubon Society, for example, supports wind power as a way to reduce greenhouse gas emissions, but urges careful planning to locate wind farms in ways that minimize risk to wildlife.
    Besides large onshore and offshore wind farms, wind turbines can be used as a distributed energy resource. With support from the U.S. Department of Energy, there have been significant innovations in smaller-scale wind turbines to integrate some of the improvements seen in larger models, including longer blades to capture more wind and advanced composite materials. Smaller turbines can even be used to help power homes, farms, schools and businesses.
    Across the U.S., several electric cooperatives and other rural utilities have deployed one or more large-scale wind turbines in their local service territories as a local utility-scale resource to supplement their wholesale power supply. These kinds of local resources can help boost resiliency, hedge or reduce power supply costs, and support local economic development.
    We’ll have to watch as wind energy and the technologies that power it evolve. For wind power, there will be opportunities for growth at both smaller and larger scales, as well as on land and offshore.