A high-resolution energy modeling approach for decarbonizing isolated power systems: A case study in the Brazilian Amazon

Access to reliable and sustainable electricity remains challenging in remote regions such as the Brazilian Amazon, where isolated power systems still rely on fossil fuels. This study introduces SISOL-AmazonBR, a high-resolution energy system model based on the Calliope framework. The model integrates hourly time series, techno-economic data, and land-use constraints to run five scenarios, including fossil fuel (FF) phase-out and complete fossil bans, with configurations powered by solar photovoltaics (PV), batteries (Bt), and green hydrogen (H 2 ). A subset of representative isolated systems was selected to explore optimized configurations that meet total demand while minimizing levelized cost of electricity (LCOE) and/or greenhouse gas (GHG) emissions. Results indicate that PV-Bt-FF systems offer the lowest LCOE under current cost assumptions, but they remain dependent on vulnerable fuel supply chains. Compared to the optimized FF baseline, PV-Bt and PV-greenH 2 -Bt configurations could reduce GHG emissions by up to 93% and 87%, respectively. However, these configurations require a significant increase in installed PV capacity, around 300% to 600% more than PV-FF. Hydrogen-based systems, while costlier, provide flexibility and resilience, making them more suitable than batteries for long-term and large-scale storage. Emission penalization mechanisms impact system design by promoting fossil fuel displacement and narrowing the economic gap between storage options. Water requirements for hydrogen are modest yet non-negligible under increasing climate stress. Site-specific factors, such as climate conditions, spatial availability, and demand profiles, influence model outcomes. The findings highlight the importance of tailoring energy transition strategies to specific contexts, balancing decarbonization with local demands and environmental conditions. The SISOL-AmazonBR model is a replicable tool that can be used to evaluate different electricity system designs in off-grid regions worldwide.