Scenario-Based Energy System Planning for Samoa's Clean Energy Transition to 2050

Pacific Small Island Developing States (PSIDS) face complex energy transition challenges arising from geographic isolation, fossil fuel dependency, land constraints, and climate vulnerability. The study conducts a techno-economic assessment of Samoa’s energy system using EnergyScope Typical Days. This study stress-tests the main transition challenges through scenario analysis. Five scenarios spanning 2025–2050 are examined: a Reference Scenario, Increasing Indigenous Primary Energy Supply, Natural Disaster Shock, Emissions-Constrained Decarbonization, and Innovation Shift. Results show that under the Innovation Shift scenario, Samoa can achieve over 85% renewable energy in total primary supply by 2050 while accommodating a 45% increase in electricity demand. Biofuels and solar photovoltaics account for up to 38% and 30% of total supply, respectively. Battery energy storage and electric vehicles enhance system resilience under disaster conditions, with up to 819 MWh of distributed EV storage required to meet 10% of national demand. Emissions-constrained pathways demonstrate escalating marginal abatement costs, rising from 470 USD/tCO 2e in 2030 to over 3, 000 USD/tCO 2e by 2050. The Innovation Shift scenario highlights a system characterised by full renewable electricity, extensive electrification, and sector-coupling through biogas and hydrogen, showing that Samoa’s long-term transition is shaped more by strategic design choices than by absolute cost values. • Adapts EnergyScope Typical Days to a small-island system with land and grid constraints • Integrates disaster shocks, sector coupling, and sequential 5-year pathway modelling • Quantifies trade-offs between cost, emissions, and resilience across five scenarios • Demonstrates limits of emissions-only optimisation without structural system change • Provides a transferable whole-energy-system framework for PSIDS energy planning