Reliable electricity supply remains limited in conflict-affected rural regions of Somalia, constraining socio-economic development and service delivery. This study designs and evaluates a hybrid photovoltaic–diesel generator–battery storage (PV–DG–BS) microgrid through techno-economic optimization, sensitivity analysis, resilience assessment, and environmental performance. Using HOMER Pro simulations supported by site data and a load-scaling approach, five system designs were evaluated, combining conventional resources, particularly diesel, with renewable energy sources, particularly solar, alongside a battery storage solution. The study identified an optimal fixed architecture comprising 12,000 kW of PV, ≈38.3 MWh of battery storage, a 5,397-kW converter, and three of 2,000-kW diesel generators operated in a load-following mode. The optimal hybrid system produces ≈21.54 GWh/yr with a renewable fraction of ≈81.3%, indicating that the majority of annual energy is supplied by PV plus storage and achieves a competitive levelized cost of energy (LCOE ≈ 0.167 USD/kWh). Compared to a diesel-only baseline, annual diesel uses falls from ≈5.18 million L to ≈0.973 million L (≈81.2% reduction). Corresponding CO₂ emissions drop from 13,584,108 kg/yr to 2,550,864 kg/yr, saving ≈11,033 tCO₂/yr. CO₂ intensity improves from 0.700 kgCO₂/kWh to 0.118 kgCO₂/kWh. One-at-a-time sensitivity runs show that LCOE is most sensitive to the discount rate and diesel price; PV and battery cost changes have a lesser impact within the tested bands. Resilience testing under realistic stress cases (solar −10% and −20%, load +15%, single DG outage, and battery −20% capacity) shows the system maintains near-full reliability. Unmet load is effectively zero for all scenarios except the single-DG outage, which caused a very small unmet fraction (≈0.0328%). Battery cycling (~203 cycles/yr) is consistent with daily peak-shaving use. The study concludes that the PV/DG/BS hybrid is technically feasible, environmentally safe, and economically robust under realistic assumptions; it recommends integrating wind and hydrogen-based storage to further increase the renewable fraction, investigating grid-connected and net-metering operations which may enhance energy availability and minimize curtailment, and evaluating socio-economic impacts.