The economy's growth affects the energy demand, increasing power plant construction to meet this demand. Hydrothermal Carbonization involves subjecting raw material to high pressure and temperature in water for a specific duration, resulting in uniform, smaller-sized solids from the high-moisture content material. The hydrothermally treated solid products share similar characteristics to solid fuel, ranging between lignite and low sub-bituminous coal. This paper suggests that municipal waste can be converted into solid fuel through hydrothermal carbonization, mixed with coal to meet power plant energy needs. The typical energy balance model simulation of the hydrothermal treatment will also be described with co-firing thermal power plant. This integrated system was thermodynamically analyzed by modelling of co-firing thermal power plant configuration with various moisture content of feed municipal solid waste using the fully flexible heat balance engineering software, THERMOFLEX. Char product was assumed by converting municipal solid waste via hydrothermal carbonization at a temperature of 210 °C and a pressure of 2 MPa for 30 min. Consequently, this study could aid in solving municipal solid waste issues and reducing coal consumption in power plants.