This paper presents a preliminary assessment of renewable energy potential for long-term electricity energy planning. In order to implement a sustainable supply-demand framework, renewable energy resources consist of geothermal and solar energy based power plants are included in a bottom-up accounting based model along with energy efficient and energy conservation approach in the demand side. The developed model is applied to a region comprises 5 cities or regencies in the eastern part of East Java province, Indonesia. The main purpose of the study is to compare several supply-demand scenarios with respect to the resources, costs, and environmental impacts over the study period. According to the analyses, the 2025 total electricity consumption of the observed area would be 6,873.8 GWh for the case of Business as Usual scenario, or increase by 203% compared to year 2014 as the baseline. Meanwhile, applying energy efficiency and conservation scenario, the growth would increase in a lower pace with 175% compared to the baseline or 6,222 GWh. Given the shortage of supply, more electricity should be imported from the interconnected system if the existing coal fired power plant is preserved through out the simulation period compared to planning involving geothermal and solar energy based power plants. In this study, geothermal and photovoltaic power plant would have their contribution toward the supply around 15.49% and 4.06%, respectively, from early year of their appearence until the last simulation year.