This thesis deals with the possibilities of using waste heat for power generation with a focusing on biogas plants (BGS). The produced biogas is mainly used for combustion in cogeneration units with internal combustion piston engines. The first part this paper describes the biogas plants. The division of BGS and the biogas processing is mentioned there. Another part is focused on the combined production of electricity and heat. The principles and description various types of cogeneration technologies are presented here. The following are specific options for waste heat utilization for biogas plants. The last section contains proposals to increase electricity production by the BGS with the steam engine and economic evaluation of these propos...