Development, modeling and optimization of a solar-hydrogen-electricity-thermal-based integrated energy system for remote cold regions

Hydrogen is a clean and sustainable energy carrier with significant potential to reduce fossil fuel dependence and mitigate energy shortages. This study proposes a novel off-grid integrated energy system (IES) for remote cold regions, incorporating solar-driven water electrolysis, hydrogen fuel cell power generation, and hydrogen-enriched methane combustion. A dynamic model was developed to evaluate system performance for electricity, heating, and gas supply. A multi-objective optimization framework was introduced, incorporating equal weight and entropy weight-TOPSIS methods to determine the system sizing. Under the two schemes, methane consumption was reduced by 18.8 % and 13.6 %, respectively. The primary investment difference was the hydrogen storage tank size, 1200  m³ for equal weight and 1300  m³ for EWM-TOPSIS, resulting in a 5.36 % higher initial cost for the latter. Following optimization, the ideal sizes for photovoltaic panels, electrolyzer, gas tank, battery, and fuel cell were identified. Comprehensive static economic and annual energy flow analyses confirm the system maintained indoor temperatures around 20 °C during the heating season, utilizing solar-generated hydrogen and low-emission hybrid combustion. The proposed solar-hydrogen-electricity-thermal-based IES provides a feasible and efficient pathway for clean energy utilization in off-grid cold regions and supports the broader deployment of hydrogen-based technologies.