Power-Sector Decarbonization Pathways in Viet Nam to 2050: An OSeMOSYS Scenario Analysis

This study uses OSeMOSYS through MUIO to compare three pathways for Viet Nam’s electricity system, reporting results for 2026–2050. All scenarios share final electricity demand and technology costs. Business as usual (BAU) retains minimum fossil-generation requirements. Renewable expansion (RE_EXP) removes these requirements and introduces a minimum eligible renewable generation share reaching 75% in 2050, covering wind, solar PV and biomass. COAL_TR adds restrictions that progressively reduce coal generation to zero by 2050 and prohibit new coal capacity from 2031. Solar and wind dominate the transition portfolios, complemented by hydropower, biomass and nuclear generation. By 2050, installed generation capacity reaches approximately 787 GW in both transition scenarios, compared with 479.7 GW under BAU. Annual direct CO₂ emissions fall to 44.5 Mt under RE_EXP and 20.8 Mt under COAL_TR, compared with 718.6 Mt under BAU. Cumulative emissions over 2026–2050 are 72.51% and 76.82% lower than BAU, respectively. Cumulative capital investment reaches USD 1,436.2 billion under RE_EXP and USD 1,461.3 billion under COAL_TR, compared with USD 1,089.1 billion under BAU. Additional investment therefore amounts to USD 347.1 billion and USD 372.2 billion. These undiscounted capital requirements exclude fuel expenditure, operating costs and salvage values and do not establish differences in total system costs or abatement costs. The shared renewable-share endpoint produces different cumulative emissions, highlighting the importance of fossil-generation constraints and transition timing. Zero coal generation also remains distinct from complete coal-capacity retirement and zero direct emissions. Comparisons with BAU reflect the combined scenario packages, including removal of fossil-generation floors. The single-region model and 20 representative time slices do not resolve regional transmission constraints or hourly reliability, while pumped-hydro deployment has no national potential ceiling.