Optimizing novel green hydrogen production from solar and municipal solid waste: A thermo-economic investigation with environmental comparison between integrated low temperature power cycles

Effectively managing global municipal solid waste (MSW) is imperative, and this study presents an innovative approach to convert MSW into green hydrogen, addressing environmental and energy challenges. The research integrates a standalone MSW and solar thermal-operated power cycle to drive a solid oxide electrolyser (SOEC) for green hydrogen production. Exploring two system layouts—Organic Rankine cycle (ORC) and Kalina cycle—the study uses solar thermal energy and MSW biogas to generate electricity for activating the SOEC. Uninterrupted hydrogen generation using solely biogas during nighttime or periods without sunlight and employing both biogas and solar thermal heat during the remaining hours. A comparative analysis shows the ORC outperforms Kalina with 16% higher thermal efficiency, 42% lower costs, and 47% reduced CO2 penalties. Kalina produces 32% more power and achieves a lower LCOH of $6.88, which can be further lowered with MSW driven systems. Multi-objective optimization demonstrates ORC's and Kalina's optimal points of thermal efficiency 15.5% and 6.23%, exergy efficiency 12.9% and 7.37%, and total investment cost $130,833 and $135,235.