DesMoines Register: Before deciding to build a conventional coal-fired generator at Marshalltown, Alliant Energy took a long look at a different coal-burning technology that holds the potential to emit less carbon dioxide pollution. Alliant executives visited two Integrated coal Gasification Combined Cycle, or IGCC, generators, in Florida and Indiana, that turn the coal into a gas that feeds the generator’s boilers rather than burning coal to fire steam generators. Advocates of the technology …