Iowa ranks first in the nation for its proportion of electricity generated from wind, as well as for distributed wind capacity, according to new reports released today by the U.S. Department of Energy. 

Wind power accounted for 36.9 percent of electricity generated in Iowa last year, the highest percentage of any state. The reports cover three market sectors: land-based utility scale, distributed, and offshore wind.

Iowa was also among the top five leading states for new utility-scale wind capacity additions in 2017, with 397 megawatts added. At the end of 2017, Iowa had a cumulative installed capacity of 7,308 MW, ranking third in the United States. 

Overall in 2017, wind energy contributed 6.3 percent of the nation's electricity supply. In 14 states, it contributed more than 10 percent of total electricity generation — and more than 30 percent in four of those states, including Iowa.

The three wind energy market reports released by the DOE “demonstrate that as wind installations continue across the country and offshore wind projects move beyond the planning process, technology costs and wind energy prices continue to fall,” the agency said in a release. 

The average installed cost of utility-scale wind projects in 2017 was $1,611 per kilowatt, down 33 percent from the peak in 2009–2010. The U.S. wind industry saw $11 billion invested in new utility-scale wind plants in 2017.

Last year Iowa also installed 63.5 MW of distributed wind capacity, more than any other state. Distributed wind capacity is defined as electrical power generation that occurs close to where the power is consumed, primarily by the system owner as “inside-the-fence” or “behind-the-meter” generation. In Iowa, most of this new capacity was from turbines larger than 1 MW being installed behind the meter and to serve utility loads on local distribution grids.

The reports also identified a new trend of “partial wind project repowering.” In 2017, 408 MW of partial repowering was completed in Iowa, resulting in increased rotor diameters and the replacement of major nacelle components.