Optimizing the development of power generation to increase the utilization of renewable energy sources

The electric power system is critical to supporting the economic growth of a country. On the other hand, the growing concern about the environment in recent years has pushed many countries to create strategies to minimize greenhouse gas emissions by increasing the proportion of new and renewable energy (NRE) sources. In Indonesia, the Java-Bali power grid is the most extensive electricity system, with a demand of 177,692.43 GWh with a peak load of 40,059.74 MW in 2019. However, the energy mix in Java-Bali is dominated by coal at 70%, followed by natural gas at 21.22%, renewable energy at 7.71%, and fuel at 0.14%. Therefore, there is an urgent need to increase the use of NRE sources in fulfilling the electrical energy demand, with the government setting a renewable energy utilization target of 23% in 2025 and 31% in 2050. This study aims to create a power-generating capacity development planning scenario with the best use of NRE sources at the lowest cost, to support the Indonesian policymakers in obtaining those targets. The Balmoral model with General Algebraic Modeling System (GAMS) programming was used to optimize the planning model for the power generating capacity. The results show that the development planning scenario with a total additional generating capacity of 15,035 MW is the scenario with the most optimal utilization of NRE sources and the lowest cost, with an estimated total investment cost of IDR 901 trillion. Furthermore, this scenario can increase the composition of renewable energy in the Java-Bali system to 16.95% in the next ten years.