Techno-financial-environmental analysis and MCDA-based sustainable selection of grid-isolated hybrid energy system for remote and rural hilly region electrification

This study proposes a reliability-constrained decision-support framework for the optimal design of an off-grid hybrid energy system (HES) for rural electrification. The objective is to systematically evaluate trade-offs among lifecycle cost (LCC), loss of power supply probability (LPSP), and lifecycle greenhouse gas (GHG) emissions across alternative battery technologies. Lead–acid (LA), lithium-ion (Li-ion), and nickel–iron (Ni–Fe) batteries are assessed under multiple reliability levels (LPSP = 0%, 1%, 3%, and 5%) and representative depth-of-discharge conditions. For each predefined scenario, particle swarm optimization (PSO) is applied to minimize LCC subject to technical and operational constraints, generating a structured set of reliability-indexed optimal configurations. The optimized configurations are subsequently evaluated using a Fuzzy-AHP multi-criteria decision-making approach that integrates economic, technical, and environmental criteria. Lifecycle GHG emissions are incorporated directly into the decision stage to ensure sustainability-oriented selection rather than cost-only ranking. Among the 24 evaluated configurations, configuration C-21 achieves the highest aggregated performance score of 0.0718. Results indicate that stricter reliability requirements substantially increase system cost and storage capacity, while battery chemistry significantly influences replacement frequency and lifecycle emissions. Although specific configurations achieve the minimum LCC under relaxed reliability constraints, the final recommended system balances performance across LCC, LPSP, and GHG emissions. A sensitivity analysis of seven key parameters shows that LCC is most sensitive to changes in the nominal interest rate, while COE is most sensitive to changes in load demand. Variations of −20% to +20% led to +20.04% to −13.44% in LCC and +10% to −5.64% in COE, respectively.