Diesel engine powered cogeneration (DEPC) plants bum heavy fuel oil, and the exhaust involves undesirable emissions such as solid particulates, sulfur oxides (SOx), and nitrite oxides (NO,). These emissions must remain below the maximum permissible levels defined by official organizations and international protocols. In this Article, allocation of emissions from a DEPC plant is studied on the basis of six main methodologies available in the literature. Results for allocated amounts of emissions are compared according to the power produced and steam generated based on energy and exergy. Exhaust emission assessment is done using fuel savings analysis method and exergetic efficiency. The results show that using separate units of power and heat production increases the fuel consumption by 23.8% in terms of thermal efficiencies, and by 17.3% in terms of exergetic efficiencies with respect to the DEPC plant.