Associated Press: The Energy Department failed to prepare a proper analysis and made a $500 million math error when it decided to shelve an experimental coal-fired power plant slated for central Illinois, according to a report from congressional auditors released on Wednesday. The project, known as FutureGen, would be located in Matoon, Ill., if the project were revived and could provide a boost for economic development in the coal-rich, east-central part of that state. But more importantly, its …