Recycle models of used edible oil in different scales were considered from the CO2 emission induced. In the models, CO2 emission was estimated systems including the consumption of used oil as “Bio Diesel Fuel (BDF)” or fuel for direct combustion using “Biomass Burner (BMB)” . Three models from a small scale of household to a city scale with 260,000 residents were compared. Because the amount of oil collected differs in each modeles, the CO2 emission was evaluated for an unit volume of the used edible oil. In case of the use for BMB in a bath facility for 250 persons located in a shopping mall, the most reduction of CO2 emission was obtained