Wind Power in Iowa - Overview

Overview

The development of wind power in Iowa began with the enactment in 1983 of a state law that required investor-owned utilities in the state to buy a total of 105 MW of power from wind generated electricity, one of first renewable electricity portfolio standards. This provided assurance to those building wind power installations that there would be a market for the electricity they produced.

Installed wind power capacity in Iowa grew quickly in 2008 and 2009. In their end of year report for 2009, the American Wind Energy Association reported that the installed wind power capacity in Iowa was 3670 MW. Only Texas has a higher amount of installed wind power capacity. Wind power installations increased by 879 MW from a year earlier. In the prior year, 2008, over 1500 MW of wind power generation was installed. Also in 2008, Iowa overtook the historical leader in wind power, California.

In 2010 and in 2009, Iowa led the U.S. in the percentage of electrical power generated by wind, at 15.4 percent and 14.2 percent. This was up from 7.7 percent in 2008, as there was a large increase in the installed capacity in 2008. In 2010 Siemens received the order to deliver 258 wind turbines to wind farms being built by Mid American Energy. Some of the wind power generated electricity is sold to utility companies in nearby states, such as Wisconsin, and Illinois.

Wind farms are most prevalent in the north and west portion of Iowa. Wind maps show the winds in these areas to be stronger on average, making them better suited for the development of wind energy. Average wind speeds are not consistent from month to month. Wind maps show wind speeds are on average strongest from November through April, peaking in March. August is the month with the weakest average wind speeds. On a daily cycle, there is a slight rise in average wind speeds in the afternoon, from 1 to 6 p.m. Estimates by the National Renewable Energy Laboratory (NREL) indicate Iowa has potentially 570,700 Megawatts of wind power using large turbines mounted on 80 meter towers. Iowa ranks seventh in the country in terms of wind energy generation potential due to the strong average wind speeds in the midsection of the U.S. The Iowa Environmental Mesonet, with over 450 stations, is a resource available to monitor current weather and wind conditions and provide data for modelling and predicting wind power.

The average capacity factor of Iowa wind farms has been estimated as 33.3% by a wind industry consultant. Several of the newer projects are the large 440 MW Rolling Hills project near Massena, the Elk Wind Farm near Greeley, and Pocahontas Prairie project northeast of Pomeroy. All were constructed in 2011, although the Pocahontas Prairie project wasn't online until early 2012.

According to the Iowa Office of Energy Independence, lack of transmission line capacity is beginning to restrict further growth of wind farms in the state. A report from the NREL acknowledges that this is a major hurdle to increased wind power development in the U.S. A high voltage DC line that would transmit power from near Sioux City to the Chicago area has been proposed.