4E analysis and optimization comparison of solar, biomass, geothermal, and wind power systems for green hydrogen-fueled SOFCs

Integrating renewable energies with hydrogen production via electrolysis and utilizing hydrogen as a fuel for solid oxide fuel cells (SOFCs) presents a synergistic approach towards sustainable energy generation. This coupling offers enhanced flexibility, allowing for efficient energy storage and distribution, thereby addressing intermittency issues associated with renewable sources. Additionally, the utilization of hydrogen in SOFCs enables high-efficiency power generation with reduced emissions, contributing to the transition towards a cleaner energy landscape. In the present study, four types of renewable energies, namely solar, biomass, geothermal, and wind, produce hydrogen by coupling power generation units and a proton exchange membrane electrolyzer (PEME). Then, the produced hydrogen is stored and used for later utilization in an SOFC subsystem. A 4E (energy, exergy, exergy-economic, and environmental) study is conducted for the proposed systems through a sensitivity study and design optimization. In the best output performance mode, the best exergy efficiency is obtained by the biomass-based system, which is equal to 9.40 %, and the lowest values for total cost rate and unit cost of outputs are achievable by the geothermal-based system, with values of 27.72 $/h and 43.23 $/GJ.