GSA Connects 2022 meeting in Denver, Colorado

Paper No. 215-5
Presentation Time: 9:45 AM


ELLIS, Geoffrey and GELMAN, Sarah E., US Geological Survey, Energy Resources Program, Denver, CO 80225

Geologic hydrogen (H2) has recently gained interest as a potential primary energy resource. To guide decision-making, policy makers, resource managers, exploration companies, and investors will need information as to the extent of the potential resource. However, the uncertainties associated with the generation, migration, accumulation, and preservation of H2 in the subsurface make it impossible to precisely determine potential resource volumes at this time. Despite the uncertainties, the occurrence and behavior of H2 in the subsurface is not completely unknown. Additional inferences on the occurrence of H2 in the subsurface can be made by employing knowledge derived from studies of fluid migration, accumulation, and preservation related to other geologic resources (e.g., petroleum, geothermal energy, noble gases, etc.). These factors can be combined to provide some constraints on the possible magnitude of geologic H2 resources in the subsurface.

A preliminary box model for the global geologic H2 resource potential has been developed using a mass balance approach. The model inputs include surface flux, trapping efficiency, residence time in traps, and biotic and abiotic H2 consumption (differentiated as shallow versus deep), which are constrained by knowledge of these factors for H2 or other analogues. Earth is assumed to currently be at steady state with respect to H2 flux from the subsurface to the atmosphere. Hydrogen consumption from future production of H2 is modeled based on historical natural gas production. Stochastic model results indicate a greater than 98% probability of geologic H2 production meeting at least 50% of the forecast green H2 production by the year 2100 and beyond, with long-term renewable H2 production potentially in the range of 100s of Mt per year. Moreover, the model indicates that the residence time of H2 in reservoirs and the annual flux of H2 to the atmosphere are the most influential factors affecting the resource potential, whereas variations in biotic and abiotic consumption of H2 have relatively little effect. These results strongly suggest that additional investigation of the resource potential of natural H2 is warranted. This model provides an initial framework for assessing global H2 resource potential and can be an important tool for guiding future research initiatives.