Abstract Refuse derive fuel and refuse plastic/paper fuel were evaluated in a direct carbon fuel cell (DCFC) system as energy sources, and two different grades of coals were also employed for comparison. The maximum power density of refuse fuels was reached up to 43–62% level comparing to that of coals, despite their significantly low carbon content. Significant properties such as thermal reactivity, nitrogen gas adsorption characteristics, and functional groups on the surface of the fuel were investigated using the TGA (thermogravimetric analysis), BET (Brunauer–Emmett–Teller test), and XPS (X-ray photoelectron spectroscopy) techniques, respectively. The correlation between fuel properties and electrochemical reactions was investigated, and it was found that the total carbon content, surface area, pore volume, and oxygen functional groups on the surface might have an influence on the reactions in the DCFC system. The effect of temperature increase from 973 K to 1023 K was restricted in the RDF (refuse derived fuel) because of its highly activated gasification phenomenon. The stirring effect could improve the performance of the RDF and the RPF only at 1023 K and 923 K, respectively, because of thermal characteristics and certain substances that affected the viscosity of the electrolyte.