In the present study, innovative energy efficiency enhancement methods and cleaner production in conventional waste-fired CHP plants are presented. This includes the medium- and low-grade solar thermal systems and flue gas condensation for feedwater heating in different arrangements. The article presents a thorough thermodynamic, economic, and environmental assessment of all the possible scenarios and then ranks the best solutions in different aspects. For making the results reliable, the solutions are applied to a waste-fired CHP plant in Denmark. For this, a transient simulation of the proposed configurations is performed via TRNSYS software for an entire year. The results indicate that the proposed models can produce more power and heat than the conventional plant but with different effectiveness factors. According to the economic results, a design consisting of a flue gas condensation circuit and parabolic trough collectors for the open and closed feedwater heater form the best configuration. The exergy assessment results indicate that the waste incinerator with annual irreversibility of 128.4 GWh is the most important component exergetically. Finally, the parametric study results show that the increase of incineration temperature significantly affects the power and heat exergy efficiency ratios.