Reunion Island, a French overseas region located in the Indian Ocean, is facing a three-fold challenge combining demographics, the environment and energy. To limit its heavy dependence on imported fossil fuels, Reunion Island aims to achieve energy autonomy by 2030 based on greater energy efficiency and renewable energy alternatives. The objective of this study is to analyze different scenarios to reach energy autonomy and, at the same time, consider the wide-scale integration of renewable energy in the island’s power system using the bottom-up optimization energy model TIMES-Reunion. Despite the tremendous potential of renewable energy sources present on the island, the transition to 100% renewable energy needs to be supported by incentives or constraints. Strong energy policies can both direct the choice of renewable resources and accelerate the renewable transition. The development of biomass on Reunion Island is economically interesting. The transition scenarios show that by 2030, electricity from biomass advantageously replaces electricity from coal and represents slightly more than 50% of electricity generation. Solar and wave/ocean energies are not the most cost effective option, but wind energy tends to disappear in the face of these energies more politically supported. A network regulation rule benefits biomass and is more detrimental to solar than to wave energy.