Abstract: A steam generation apparatus includes a primary source of hot water supplied to an enclosed hot water receptacle maintained at a pressure of approximately 300 psi. Supply and return lines pump the hot water in a recirculating manner through a serially connected supplemental heating device until the hot water has reached a temperature of substantially 400.degree. F. whereupon a thermal valve associated with the supplemental heating device opens to deliver the heated water to an expansion tank. Steam formed within the expansion tank is transmitted through a steam outlet line to appropriate using apparatus. The initial hot water source may alternately include industrial by-product heated waste water on a primary heating station serially connected between a water supply and the enclosed hot water receptacle. Water condensed in the expansion tank is recycled to either the hot water receptacle or primary heating station.