Cedar Rapids-based Alliant Interstate Power and Light plans to build a 400-million-dollar electric plant on one of two sites in Buchanan and Cerro Gordo counties. John Ruff, spokesman for the parent company Alliant Energy, says the plant won’t just generate power, it’ll generate revenue with hundreds of construction jobs and later full-time jobs. The new plant would generate 500-megawatts of power and should be running by 2004. Ruff says the residents of the two counties will help the utility decide where to build. He says the public support will determine where the plant is built.Ruff says a decision on which county will get the plant should be made within three to four weeks. He says Iowa may be facing an energy shortfall by the time the new facility is ready to be switched on. He says energy consumption continues to rise with the use of computers and other electronic appliances.The new electric plant will be natural gas-fired. Alliant is also considering building a coal-fired generator site in Burlington, Clinton, Marshalltown or Ottumwa.