A comprehensive techno-economic planning framework for isolated microgrids with hybrid battery-hydrogen storage: a two-stage optimization approach

Isolated microgrids powered by renewable sources face significant operational challenges due to generation intermittency and the lack of external grid support. To address this challenge, this study proposes a two-stage techno-economic planning framework integrating a hybrid battery-hydrogen energy storage system. Renewable uncertainty is modeled using a Markov Chain Monte Carlo (MCMC) approach validated against 10 years of historical meteorological data, combined with an adaptive time-horizon compression technique that reduces computational burden by 52.3%. A multi-timescale operational coordination strategy is implemented, where battery storage handles intraday variability and hydrogen storage provides long-term seasonal balancing via an improved Particle Swarm Optimization algorithm. Applied to a 300 kW isolated community microgrid in Pakistan, the proposed hybrid framework reduces total annualized system cost by 15.3% (from $394.8 k to $328.5 k) compared to battery-only configurations. Furthermore, the system achieves 76.4% renewable penetration, ensures 99.98% reliability for critical loads, and reduces operational CO₂ emissions by 97.7% relative to traditional diesel-only systems, with a resulting Levelized Cost of Energy (LCOE) of $0.328/kWh .