MidAmerican Energy plans to build the world’s largest wind farm in northern Iowa while at the same time the company has promised to freeze electric rates for its Iowa customers ’til 2010. Jack Alexander, MidAmerican vice president in charge of power generation, says that means customers will go 15 years without an electric rate increase.Alexander says the company’s trying to be as efficient as they can because they can’t expect customers to bear the cost of building power generating stations. The wind farm project will cost in the neighborhood of 323-million dollars, and will feature as many as 200 wind turbines. Alexander says the turbines may be placed at “multiple sites” in northwest and north central Iowa. MidAmerican expects all the wind turbines to be up and running by 2006.MidAmerican’s plan must win the endorsement of state regulators, and requires some changes in state law that must be endorsed by the Iowa Legislature.