Decarbonizing Indonesia’s power system: exploring the potential of energy storage systems for a sustainable energy transition

Indonesia’s power sector is the country’s largest source of energy-related carbon emissions, with coal-based generation rising to 66% by 2020 despite national and international decarbonization targets. The Just Energy Transition Partnership (JETP) outlines an ambitious vision to reduce emissions and scale renewables, but achieving these goals requires flexible and coordinated grid planning, especially in systems with high variable renewable energy (VRE) penetration.

This study evaluates the role of energy storage systems (ESS) in supporting decarbonization in the Java-Bali power grid using a mixed-integer quadratic programming (MIQP) unit commitment model. The framework simulates hourly dispatch and regulation reserve across Moderate and Deep Decarbonization pathways from 2025 to 2050, incorporating carbon taxes, curtailment penalties, ESS operational constraints, and seasonal VRE variability.

Results show that ESS reduces curtailment by up to 20.1 TWh (Moderate) and 26.5 TWh (Deep) in 2050, with corresponding system cost savings of USD 2.14–2.22 billion under base VRE conditions. Emission reductions reach 1.9–3.2 MtCO₂, however rebound due to fossil-based charging under aggressive ESS deployment scenarios can raise emissions by up to 1.25 MtCO₂, highlighting the importance of strategic dispatch.

These findings confirm ESS as a critical enabler of renewable integration and cost reduction but also emphasize the need for emissions-informed dispatch and integrated planning. The analysis provides a quantitative foundation to support the JETP’s implementation and highlights policy levers needed to align ESS deployment with national decarbonization goals.