MidAmerican said it planned to buy up to 650 turbines for the new capacity. If the company, which is the state's largest utility, installs the maximum amount it is likely it will be using GE 1.6MW machines.
The company added that the new capacity would be installed at no additional cost to consumers. However, in July last year, the Iowa Supreme Court ruled in favoor of letting MidAmerican raise consumer rates to help pay for new wind generation.
The court's 5-0 ruling upheld a 2009 decision by the Iowa Utilities Board, which was challenged by NextEra Energy, the nation's leading wind developer. NextEra claimed MidAmerican did not properly explore other options for adding new capacity, including the purchase of existing wind power and wind farms from competitors.
To date, MidAmerican has installed 1,267MW in Iowa since 2004. In a statement, it said it believed it could supply 39% of its retail electricity through wind power.
Speaking about the new capacity, Bill Fehrman, president and CEO of MidAmerican Energy, said: "The proposed wind expansion will not only add to MidAmerican Energy's and Iowa's position as a national leader in wind generation capacity, it will help reduce future rates to our customers by as much as $10 million per year and further enhance our corporate principle of environmental respect by reducing our carbon footprint by 10.3%."