In a statement, MidAmerican said it planned to start building the projects in spring next year with completion planned for the end of 2016.
The company said the projects will cost around $900 million. Speaking about the developments, MidAmerican CEO Bill Fehrman said: "Wind continues to be a factor in keeping our customers' electricity rates among the lowest in the nation."
According to Windpower Monthly's data division, Windpower Intelligence, MidAmerican had around 1.3GW installed in the US at the end of 2014. Projects include 444MW Rolling Hills, which came online in 2011.
In January, MidAmerican completed work on four of the five wind projects that will make up its 1.1GW Wind VIII block in Iowa.
It said it expects to complete the fifth and final project, the 495MW Highland development, by the end of the year.