Hydrogen production via using hybrid renewable energy and waste fuels derived systems incorporating heat recovery and carbon capture measures

Contemporary societies face several challenges in waste management, especially for those involved with Refuse-derived fuel (RDF) and Tire-derived fuel (TDF). In addition, sustainable access to affordable and reliable energy becomes essential. The current study leverages Saudi Arabia's abundant waste and renewable power sources, adopting six scenarios for hydrogen production via low and high temperature electrolyzers. The burner uses the waste fuel to provide steam for the electrolyzer, where the renewable sources provide the required electrical power. Moreover, a novel waste heat utilization technique is adopted to enhance system performance via the outlet hot streams for water heating and the high-temperature streams for Stirling engine power production. The results revealed that waste fuel analysis is vital to estimate its full characteristics in waste management. For the same rated capacity, the wind turbine configurations outweigh the PV systems in terms of electricity generation, hydrogen production, and energy efficiency. Furthermore, the overall performance ranges from 11.3 to 26.16 %, which is attributed to the positive influence of the Stirling engine and high temperature electrolyzer on the total performance. Due to TDF's high heating value, the specific fuel consumption for hydrogen production is lowered to 0.22 kg_fuel/kg_H2. The hydrogen cost ranges between 2.8 and 5.1 $/kg_H2 with a payback period from 6.18 to 14.2 years, validating the clean energy transition. Adopting degradation rates to simulate real conditions during operation, the production cost can reach 3.88 $/kg_H2 in the worst scenario. Finally, the system can reduce about 46.2 tons of CO₂/year through integrating a carbon capture unit.