MidAmerican Energy Co.'s $1.9 billion investment in more Iowa wind towers will focus on projects in five counties, the company announced today. The wind farm sites will be in Grundy, Madison, Marshall, O'Brien and Webster counties, officials said in a press release. The Vienna II project in Marshall County will be expanded, company spokeswoman Abby Bottenfield said, but the other four will be new projects. Specific locations and sizes of each project will be announced once all negotiations are finalized, she said. The expansion will add 1,050 megawatts of wind generation in the state by year-end 2015, increasing MidAmerican's electric generation capacity from wind to 39 percent of its production portfolio.