A novel electro-thermal-storage system for multi-energy supply and peak shaving in off-grid areas: A theoretical design, optimization and off-design study

A novel electro-thermal-energy storage hybrid system integrating proton ceramic fuel cell, gas turbine, and advanced adiabatic compressed air energy storage via electro-thermal coupling is proposed, offering a feasible solution for multi-energy supply and peak load shifting in off-grid remote rural areas. A performance analysis model encompassing energy, exergy, economic, and peak-shaving metrics is constructed by quantifying multi-irreversible losses based on multi-cross theory. System performance characteristics under four operation modes formed by fuel (H2/NH3) and turbine inlet pressure (constant/variable) are analyzed while ensuring the model reliability. The local to global influence mechanisms of eleven parameters on the thermo-economic and peak-shaving performances in four modes and the optimal design under four-objective optimization are investigated. The effects of three off-design parameters on system performance and corresponding adjustment strategies are deeply discussed. Results show the minimum loads of H2/NH3 systems are 78.23/23.07 kW, with maximum loads of 1500.80/1445.64 kW. Mode A achieves 635.15 kWh net electricity per cycle, 60.97 % round-trip exergy efficiency, 0.1009 $ kWh−1 levelized cost of electricity (LCOE), 12.69-year payback period (PP), and load ratios of 14.82 %–233.57 % of base load. Compared to PCFC/GT system, PP is reduced by 12.12 %, while LCOE increases by 7.45 %. Sobol-based global sensitivity analysis indicates outputs are sensitive to current density and charge-discharge air flow rates, but insensitive to temperature. Optimized mode A demonstrates 644.94 kWh, 74.22 %, 0.0920 $ kWh−1, and a wider load range. Variable-speed adjustment of compressor enables H2 systems to operate at 7.41 %–51.55 % of base load, while turbine inlet pressure throttling allows operation at 143.81 %–233.57 %.