That could bring the utility's investment in Iowa wind power to about $1.75 billion.
The Iowa Utilities Board approved MidAmerican's request to add up to 540 megawatts of new wind power. Spokesman Allan Urlis said the utility hopes to spread the more than 300 new turbines among seven sites across the state. New sites would be near Walnut, Adair, Carroll, Spencer, Orient and Charles City.
The utility already has access to property near Pomeroy. If all the turbines are built, MidAmerican will be generating 1,000 megawatts of wind power in Iowa. The utility also purchases 109 megawatts of wind power from another utility in Iowa.
If this latest project is fully built, renewable energy will total about 18 percent of MidAmerican's fuel sources, displacing the equivalent in carbon dioxide of 682,000 cars, or 43 percent of Iowa's cars. The wind power generated by MidAmerican turbine, existing and proposed, would be enough to run 336,000 homes.
The utility will draw upon federal tax credits to help underwrite the cost of the turbines. Urlis said the utility intends to have the turbines built by the end of 2008. MidAmerican recently brought a wind turbine at the Iowa State Fairgrounds online.
The turbine generates a half-megawatt of electricity, or about 25 percent of the fair's needs, Urlis said.