Diesel engines can be operated in a dual-fuel mode with low-energy gas, also called LEG, from thermal gasification or with biogas from anaerobic digestion. This paper compares the operating characteristics of a 34-kilowatt (kW) diesel engine operating in due-fuel modes with the operating characteristics of the same engine fueled with diesel oil. Performance curves comparing torque, speed, power, air ratio, effective efficiency, and exhaust temperature are presented for each mode of operation.