The Ames Fire Department is trying to figure out what caused a fire at the municipal power plant. The department says they responded to a fire at the refuse derived fuel bin at the Resource Recover plant at about 9:35 Friday morning. It was first reported by an Ames Electric Services employee who saw smoke and fire from the top of the bin. The fire department says the fire was contained but crews remained on site to monitor hot spots and help clean up. No damage estimate was immediately available and no injuries were reported.