A comprehensive comparison of battery, hydrogen, pumped-hydro and thermal energy storage technologies for hybrid renewable energy systems integration

This study presents a comprehensive, quantitative, techno-economic, and environmental comparison of battery energy storage, pumped hydro energy storage, thermal energy storage, and fuel cell storage technologies for a photovoltaic/wind hybrid system integration. The objective is to minimize the hybrid system's net present cost (NPC) while maintaining a specific loss of power supply probability. To achieve this goal, the cuckoo search algorithm is used to simultaneously optimize the number of solar panels, wind turbines, and battery banks, alongside the capacity of the electric heater, thermal storage, power block, hydraulic pump/turbine, upper water tank, electrolyzer, fuel cell, and hydrogen tank. To conduct the investigation, twelve distinct scenarios representing integrated energy systems are optimized and compared technically, economically, and environmentally. The scenarios include combinations of photovoltaic panels, wind turbines, battery energy storage, pumped-hydro energy storage, thermal energy storage (TES), and fuel cell storage technologies. These scenarios are evaluated against three realistic electrical load demands, representing the power requirements for heavy activity (HA), medium activity (MA), and small activity (SA), commonly encountered in Kousseri, Cameroon. The results show that the photovoltaic/Wind/TES system is the most cost-effective configuration for satisfying the SA, MA, and HA electrical load demands. The obtained optimal number/capacity of components and cost of energy (COE) of the PV/Wind/TES hybrid systems are as follows: For SA, the optimal system integrates 17 solar panels, 1 wind turbine, 0.67 kW inverter, 19 kW thermal storage, 3.74 kW electric heater, and 1.90 kW power block, with a NPC of 11,989.90$ and a COE of 0.2218$/kWh. For MA, the ideal configuration includes 25 solar panels, 1 wind turbine, 1.13 kW inverter, 31 kW thermal storage, 5.29 kW electric heater, and 3.23 kW power block, with a NPC of 17,390.08$ and a COE of 0.2277$/kWh. For HA, the best configuration includes 42 solar panels, 1 wind turbine, 2.10 kW inverter, 48 kW thermal storage, 7.98 kW electric heater, and 5.36 kW power block, with a NPC of 27,444.29$ and a COE of 0.2100$/kWh. Furthermore, the sensitivity and the break-even grid expansion distance analyses revealed that the thermal energy storage is always the most affordable option regardless of load profiles, resource levels, and energy storage costs.