Thermodynamic evaluation of solar energy-based methanol and hydrogen production and power generation pathways: A comparative study

This work presents a comparative evaluation of two distinct fuels, methanol and hydrogen, production and power generation routes via fuel cells. The first route includes the methanol production from direct partial oxidation of methane to methanol using solar energy, where the methanol is condensed, stored, and sent to a direct methanol fuel cell. The second route is hydrogen production from solar methane cracking (named as turquoise hydrogen), where heat is supplied from concentrated solar power, and hydrogen is stored and directed to a hydrogen fuel cell. This study aims to provide insights into these fuels' production conditions, storage methods, energy, and exergy efficiencies. The proposed system is simulated using the Engineering Equation Solver software, and a thermodynamic analysis of the entire system, including all the equipment and process streams, is performed. The methanol and hydrogen route's overall energy and exergy efficiencies are 39.75 %, 38.35 %, 34.21 %, and 33 %, respectively. The highest exergy destruction rate of 1605 kW is observed for the partial oxidation of methane to methanol. The methanol and hydrogen routes generate 32.087 MWh and 11.582 MWh of electricity for 16-hour of fuel cell operation for the same amount of methane feedstock, respectively. Sensitivity analysis has been performed to observe the effects of different parameters, such as operating temperature and mass flow rate of fuels, on the electricity production and energy efficiencies of the systems.