Wind power is rapidly altering energy portfolios worldwide.
Page last updated 9/20/2018
As of 2018, 89,077 MW of wind power are installed across 41 states, enough to power 26 million American homes.
Iowa produced 36.9% of its electricity from the wind in 2017; coal electricity production was down to 44.2%
“Over the past decade, world wind power capacity grew more than 20 percent a year, its increase driven by its many attractive features, by public policies supporting its expansion, and by falling costs.
“By the end of 2014, global wind generating capacity totaled 369,000 megawatts, enough to power more than 90 million U.S. homes. Wind currently has a big lead on solar PV, which has enough worldwide capacity to power roughly 30 million U.S. homes.” [The increase in wind power generated in 2014 alone was over 50 GW.]
“China is now generating more electricity from wind farms than from nuclear plants, and should have little trouble meeting its official 2020 wind power goal of 200,000 megawatts. For perspective, that would be enough to satisfy the annual electricity needs of Brazil.
“In nine U.S. states, wind provides at least 12 percent of electricity. Iowa and South Dakota are each generating more than one quarter of their electricity from wind.
“In the midwestern United States, contracts for wind power are being signed at a price of 2.5¢ per kilowatt-hour (kWh), which compares with the nationwide average grid price of 10–12¢ per kWh.
“Although a wind farm can cover many square miles, turbines occupy little land. Coupled with access roads and other permanent features, a wind farm’s footprint typically comes to just over 1 percent of the total land area covered by the project, something illustrated in the following picture.”
“Wind energy yield per acre is off the charts. For example, a farmer in northern Iowa could plant an acre in corn that would yield enough grain to produce roughly $1,000 worth of fuel-grade ethanol per year, or the farmer could put on that same acre a turbine that generates $300,000 worth of electricity per year. Farmers typically receive $3,000 to $10,000 per turbine each year in royalties. As wind farms spread across the U.S. Great Plains, wind royalties for many ranchers will exceed their earnings from cattle sales.”
Recently, 140% of Denmark’s electricity demand came from wind turbines, allowing it to export wind power to Norway, Germany and Sweden. 
US wind farms are producing records too (Xcel Energy Colorado — 61.1% of demand on 11/1/2014) as illustrated on the following map, showing that large amounts of wind energy can be reliability integrated into our power grid today:
A recent report by the National Renewable Energy Laboratory examined studies by grid operators and other experts, which have unanimously found that wind energy can reliably provide at least 24 to 50 percent of our electricity. 
For more on this topic see The Age of Wind chapter in “The Great Transition.”