Design and Performance Evaluation of a Low-Cost Solar Microgrid for Rural Electrification in Bangladesh

Rural Bangladesh still contains hard‑to‑reach islands, chars and riverine communities where grid extension is expensive and vulnerable to storms and flooding. This paper presents the design and performance evaluation of a cost‑constrained, PV‑battery‑diesel hybrid microgrid sized for about 1,000 connections in a coastal char context. The design is grounded in Bangladesh’s measured solar resource (Global Solar Atlas) and policy/market conditions (IDCOL financing, tariffs, net‑metering guidelines). Using current component cost benchmarks (IRENA, BloombergNEF) and fuel price data, we model levelized cost of electricity (LCOE), energy delivery and backup performance over a 20‑year horizon. The reference plant is a 330 kWp PV array, 1.2 MWh LiFePO₄ storage, and a 150 kVA diesel genset feeding a three‑phase low‑voltage distribution network. Unsubsidized LCOE is estimated at 0.41 USD/kWh; with a representative IDCOL‑style capital grant the effective LCOE falls to 0.27 USD/kWh, broadly consistent with reported mini‑grid tariffs of about BDT 30-32 per kWh. The system delivers about 442 MWh/year with an 8–12% diesel share under conservative assumptions, and maintains service during multi‑day low‑irradiance events via battery plus right‑sized genset. Sensitivity analysis shows the LCOE is most affected by distribution network CAPEX, battery replacement pricing, and demand realization. We discuss implementation risks, grid‑arrival strategies, and productive‑use enablement. The results indicate that, in Bangladesh’s remaining off‑grid pockets, carefully engineered PV‑battery microgrids can meet 24/7 demand at a cost in line with observed tariffs, while cutting local air pollution and diesel exposure. Key data are provided to support replication and peer review.