A novel integrated renewable-based energy system for production of synthetic diesel is proposed and simulated in this study. This system merges solid oxide electrolyser (SOE), entrained gasification (EG) and Fischer-Tropsch (FT) technologies. Two case scenarios are considered here. In the first case, the electrolyser unite produce syngas through co-electrolysis of steam and carbon dioxide, while in the second case only steam is electrolyzed. The effects of SOEC and EG operating pressure and temperatures on the system performance in each case are investigated and compared. It is shown that the operating condition of electrolyser subsystem has a more considerable effect on the performance of the integrated system as compared to the gasification subsystem. Also waste heat recovery results in about 43 and 2 percentage point increase in energy and exergy efficiency, respectively. It is also shown that internal recovering of oxygen has the best effect on the system performance. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.