Decarbonization Pathways for Indonesia's Power Sector: An OSeMOSYS Scenario Analysis

This study employs the Open Source Energy Modelling System (OSeMOSYS) to analyze alternative decarbonization pathways for Indonesia’s power sector to 2050, in line with the National Electricity Plan (RUKN 2025-2060) and the government’s Net Zero Emission 2060 target. Three scenarios are examined: a Business as Usual (BAU) pathway reflecting historical trends, a policy driven RE 60% scenario incorporating carbon capture and storage (CCS) and nuclear power, and a Net Zero Emission RE 100% scenario excluding coal and CCS. The analysis considers electricity demand growth, generation mix, installed capacity, greenhouse gas (GHG) emissions, and system costs, with the objective of identifying trade offs between affordability, sustainability, and reliability. The results reveal marked differences among the scenarios. The BAU pathway remains highly dependent on fossil fuels, resulting in emissions of 503 MtCO₂ by 2050, with renewables constituting only 20.4% of installed capacity. The RE 60% scenario achieves substantial emissions reductions to 21 MtCO₂ in 2050 through CCS retrofits and nuclear deployment. However, it incurs the highest discounted system cost (USD 1,468 billion), largely due to the capital intensity associated with CCS technologies. By contrast, the RE 100% scenario entails the most extensive system expansion (209.47 GW by 2050) but achieves net zero emissions by 2050 while delivering the lowest total discounted cost (USD 1,240 billion), even lower than BAU, owing to early renewable deployment and fuel cost savings.The findings carry significant policy implications, showing that partial decarbonization strategies reliant on CCS are economically less attractive than full decarbonization, as they incur the highest system costs while delivering only moderate reductions in fossil fuel dependence. In contrast, the RE 100% pathway demonstrates that a full transition to renewables and nuclear can achieve net zero emissions at 2050 while minimizing long term system costs. These results suggest that prioritizing early and decisive investments in renewable energy and nuclear capacity provides both environmental and economic advantages, positioning Indonesia on a more cost effective trajectory toward its NZE 2060 target.