Innovative technology for underground clean in situ hydrogen generation: experimental and numerical insights for sustainable energy transition

Hydrogen production in subsurface reservoirs attracts global research interest for its potential in sustainable energy generation and climate change mitigation. However, limited experimental data make optimizing in situ hydrogen generation (ISHG) processes under reservoir conditions challenging. ISHG combines reverse methane combustion with steam methane reforming (SMR), leveraging existing reservoir infrastructure to generate hydrogen efficiently while minimizing surface emissions. The primary objective is to enhance hydrogen yield by investigating key variables, such as catalyst type, water saturation, and cyclic operational modes. Results indicate that cyclic combustion followed by SMR can boost hydrogen yield by up to 68 % in controlled reservoir settings, utilizing combustion heat to drive reactions efficiently.Additionally, the in situ catalyst delivery system developed here achieved a sustained hydrogen production rate of 49 %, significantly improving process stability and scalability. Numerical simulations demonstrated that adjustments in methane combustion kinetics, validated through history matching, lead to improved alignment with observed temperature profiles and hydrogen production rates. By integrating experimental data with numerical modeling, this research provides foundational insights for environmentally sustainable ISHG applications, offering substantial greenhouse gas reductions compared to conventional hydrogen production methods. These findings underscore ISHG's promise as a transformative, low-emission technology for clean energy generation.