Three bioenergy technologies, gasification, Biodiesel fuel production, and H-2-CH4 fermentation processes, were modeled using ASPEN PLUS. A comparative performance was analyzed for different regions and scales. The proportions of feedstock were set corresponding to urban, suburban and rural regions. Verification of the simulation with our experiment indicated adequate validation to simulate using our model designs. Advantage of scale was found in the H-2-CH4 fermentation process, while total efficiency in the gasification process was considered to be affected greater to feedstock proportion by region category than to scale. Then, combined system of the three processes was simulated to assess advantages to the combining bioenergy technologies. Compared with the non-combined system, the combined system has high efficiencies because sludge and glycerol discharged from the three individual processes were fed again as feedstock into the combined system, and the sludge for the combined system was dried using waste heat exhausted from gas engine.