MidAmerican Energy Co.'s electricity customers in Greater Des Moines will have the opportunity next week to comment on a proposed rate increase. On May 17, MidAmerican filed a petition with the Iowa Utilities Board proposing a total increase in base rates of approximately $135.6 million, to be phased in over three years. If approved, rates for residential, business, industrial and lighting customers in Iowa would increase an estimated 3.6 percent beginning Aug. 15, followed by increases of 3.5 percent and 3.3 percent in 2015 and 2016. MidAmerican's rate filing also includes a 10-year proposal to equalize rates across its three service zones, which have differed since the company was formed through a merger in 1995. The utility is also seeking to add two adjustment clauses to customers' monthly bills for energy and transmission costs. One of eight public hearings scheduled around the state will be held in Des Moines on Monday, June 17, at 5:30 p.m. at the Iowa Utilities Board/Office of Consumer Advocate Building,1375 E. Court Ave. More information and access to an electronic comment form may be found at the board's website, http://iub.iowa.gov.