Decarbonization Via Microwave-Assisted Carbon-Zero HydrOgen Production from PEtroleum Reservoirs (HOPE Process): Support or Competitor to Conventional Methods?

Abstract Hydrogen is a key sustainable energy carrier crucial to global decarbonization. While green, blue, turquoise, and grey hydrogen are favored for their low carbon footprints, traditional methods including steam methane reforming (SMR), autothermal reforming (ATR), partial oxidation (POX), coal, and biomass gasification struggle to achieve carbon neutrality. This has prompted the exploration of HydrOgen production from PEtroleum reservoirs (HOPE), a novel technique utilizing microwave-assisted heating to produce low-carbon or carbon-zero hydrogen. However, a comprehensive juxtaposition of this emerging technology with conventional methods is absent from the literature. This study addresses the gap by evaluating the HOPE process alongside these methods. The evaluation criteria encompassed energy efficiency, environmental impact, and economic feasibility. Data were sourced from peer-reviewed studies and industry reports to benchmark HOPE process against traditional methods. Key technical gaps were also identified to guide ongoing research and enhance operational efficiency. The analysis revealed that the HOPE process requires no water and emits 0–13 kg CO2e/kg H2. In contrast, SMR and ATR consume 4.62–6.39 gallons/kg H2 and release 8.0–11.0 kg of CO2e/kg H2. Gasification releases 0.90–3.23 kg CO2e/kg H2 but consumes 21–893 gallons/kg H2, raising concerns in water-scarce regions. Integrating carbon capture and storage reduces emissions, but it increases production costs by 35–135%, highlighting a trade-off between environmental and economic feasibility. In the HOPE process, natural catalysts in rocks suffer from coking and sintering, limiting their long-term effectiveness. These issues are also observed in SMR and ATR. Despite HOPE’s higher energy demands compared to SMR, ATR, and POX, higher temperatures can be achieved with less microwave power inputs during thermal runaway. The process is also proposed to be compatible with existing petroleum infrastructure, facilitating rapid adoption with minimal capital investment. However, further improvements in microwave reactor design and energy delivery systems are needed to lower costs and energy intensity. Though not yet a replacement for conventional production routes, HOPE could complement existing methods, support decarbonization goals, and contribute to hydrogen economy development. This work presents a foundation for integrating microwave-assisted systems into global hydrogen economies by clarifying their strengths and limitations, and potential contributions to decarbonizing the fossil fuel industry.