This study investigated the thermochemical characterization of oil palm fronds (OPF), coconut shells (CS) and wood for their use as a solid fuel for thermal conversion processes. The ultimate analysis, proximate analysis, calorific values, and elemental contents through energy dispersive X-ray spectroscopy of OPF, CS, and wood samples were measured. The results of OPF and CS were compared with wood considered as benchmark solid fuel. Proximate analysis was performed as per ASTM standard procedure in a muffle furnace and used thermos-gravimetric analysis technique. The ultimate analysis was used to determine the weight percentage of carbon, hydrogen, and nitrogen in CHNS analyzer. Elements analysis was done using energy dispersive X-ray spectroscopy. The ultimate analysis results show carbon content was higher in CS as compared to OPF and wood. The hydrogen content was higher in OPF. Proximate analysis results revealed that volatile matter was higher in wood, whereas fixed carbon and higher heating value were found higher in CS while ash content was lower in CS. From EDX results found that the OPF has Al, Si, Cl, and K, while, in wood and CS these elements are absent. The thermochemical characterization results of OPF and CS were comparable with the wood. Therefore, it concluded that OPF and CS have the potential to be used as renewable energy source by using appropriate energy conversion technologies, such as gasification, pyrolysis, and torrefaction. © 2018 The Authors, published by EDP Sciences.