Wind power plants require careful planning
Operating a wind power plant is more complex than simply erecting wind turbines in a windy area. Wind power plant owners must carefully plan where to position wind turbines and must consider how fast and how often the wind blows at the site.
Good places for wind turbines are where the annual average wind speed is at least 9 miles per hour (mph)—or 4 meters per second (m/s)—for small wind turbines and 13 mph (5.8 m/s) for utility-scale turbines. Favorable sites include the tops of smooth, rounded hills; open plains and water; and mountain gaps that funnel and intensify wind. Wind resources are generally more favorable for electricity generation at higher elevations above the earth’s surface. Large wind turbines are placed on towers that range from about 500 feet to as much as 900 feet tall.
Map of U.S. wind resources
Source: National Renewable Energy Laboratory, U.S. Department of Energy (public domain)
Wind speeds vary hourly and seasonally
Wind energy resources vary hourly and seasonally throughout the United States. Wind speeds generally change throughout the day and from season to season. For example, in Tehachapi, California, where numerous wind turbines are located, the wind blows more frequently from April through October than it does in the winter, and the wind is usually strongest in the afternoon. These fluctuations are a result of the extreme heat of the Mojave Desert during summer months. As the hot air over the desert rises, the cooler, denser air above the Pacific Ocean rushes through the Tehachapi mountain pass to take its place. In Montana, strong winter winds channeled through Rocky Mountain valleys create more intense winds during the winter.
Fortunately, the seasonal variations in wind speeds in California and Montana match the electricity demands of consumers in those states. In California, people use more electricity in the afternoon and during the summer. In Montana, people use more electricity, in general, during the winter.
Locations of U.S. wind power projects
In 2020, 42 states had utility-scale wind power projects, which together generated a total of about 338 billion kilowatthours (kWh).1 The five states with the most electricity generation from wind in 2020 were Texas, Iowa, Oklahoma, Kansas, and Illinois. These states combined produced about 58% of total U.S. wind electricity generation in 2020.
Monthly and annual U.S. national and state-level electricity generation data are available in the U.S. Energy Information Administration’s (EIA) Electricity data browser, and hourly generation data by fuel/energy source for the lower 48 States by region are available in the Hourly electric grid monitor.
International wind power
World wind electricity generation has also increased substantially in recent years. In 1990, 16 countries generated a total of about 3.6 billion kWh of wind electricity. In 2010, 105 countries generated about 340 billion kWh, and in 2019, 127 countries generated about 1,419 billion kWh of wind electricity.
The top five countries in wind electricity generation and their percentage shares of total world wind electricity generation in 2019 were
- United States–21%
- United Kingdom–5%
Wind turbines in the ocean
Source: Stock photography (copyrighted)
Offshore wind power
The waters off the coasts of the United States have significant potential for electricity generation from wind energy. The U.S. currently has one operating offshore wind energy project: the Block Island wind farm off the Coast of Rhode Island with 30 megawatts (MW) of electricity generation capacity. Several other wind projects off the U.S. East Coast are in the planning stages. Twelve European countries had operating offshore wind energy projects as of the end of 2020.
1Utility-scale facilities (wind farms) have at least one megawatt of electricity generation capacity.
Last updated: March 17, 2021