Alliant Energy will build a 400-million dollar natural gas-fired power plant in northern Iowa near Emery which is between Clear Lake and Mason City. Executives from the utility were joined by state and local officials at a news conference yesterday in Cerro Gordo County. Eliott Protsch, president of Interstate Power and Light — an Alliant subsidiary, says community support for the project was overwhelming.Protsch says the project will be a big boost for the north-central Iowa economy, creating 400 construction jobs and generate millions in taxes and payroll dollars.Protsch says utility company mergers made the project possible.Governor Tom Vilsack say the project’s a great boost for the state.Vilsack says it’s an example of how local officials, by being aggressive, can land economic development projects. After getting the go-ahead from regulators, Alliant officials expect the plant to be on line by summer of 2004.