A bale boiler incinerates bales of material, and particularly bales made from waste, garbage and other refuse, in order to provide heat for a steam turbine generator, and includes a conveyor for transporting bales of waste material through a three-stage boiler. The boiler is preferably divided into three stages: 1) the warming stage, 2) the main incineration stage, and 3) the supplemental incineration stage. In the warming stage, the bale is warmed and dried. In the main incineration stage, the bale is burned to create heat that is then used to power a steam turbine electrical generator or the like. In the third, supplemental incineration stage, the remnants of the bale burn down to ash, and the remaining ash and non-combustible waste are then transported out of the boiler by the conveyor and dumped into a receptacle or container for transport and disposal.