In situ hydrogen generation from underground fossil hydrocarbons

Hydrogen is essential for achieving net-zero emissions by 2050, acting as both an energy carrier and source. It can store renewable energy, decarbonize difficult sectors, and serve as a zero-carbon feedstock. Conventional hydrogen production methods, such as natural gas reforming, inherently produce CO2. Electrolysis, though CO2 free during operation, can still contribute to emissions through the construction of the energy source and electrolyzer; however, using surplus renewable energy that would otherwise be wasted can offset this. In situ hydrogen generation from underground fossil hydrocarbons presents a compelling alternative. This method produces hydrogen directly within geological formations, using existing fossil fuel resources and infrastructure while keeping CO2 sequestered underground, thus minimizing environmental impact and reducing the need for extensive surface processing. Our research examines various in situ techniques, including thermochemical and biological processes, showcasing their potential to enhance current hydrogen production methods. Despite its promise, this approach faces significant challenges and requires extensive research to overcome these hurdles. Addressing these challenges is crucial for integrating this method into the global energy transition, potentially reducing the carbon footprint of hydrogen production and advancing toward cleaner energy systems. This paper highlights the necessary steps and the long path ahead to make in situ hydrogen generation a viable and sustainable solution.