Fuel demand analysis on the optimization result of sustainable electricity system expansion planning in West Kalimantan within period of 2021-2050 has been carried out using the supply optimization modeling with the least cost principle. Three scenarios have been taken into account i.e.: Scenario-1 considers the business-as-usual demand with externalities and no coal power plant addition, Scenario-2 considers additional energy demand from industrial development policy, and Scenario-3 considers the energy demand on the electricity consumption target per capita as stated in Indonesia National Energy Policy. The result of accumulated fuel demand simulation during the period was 2,592,246 Tera Joule (TJ) for Scenario-1; 3,339,517 TJ for Scenario-2; and 4,140,490 TJ for Scenario-3, respectively.