Geologic Hydrogen
Hydrogen is a clean energy carrier that could play a central role in the global shift toward sustainable energy systems. In the geologic environment, hydrogen is naturally generated during serpentinization reactions, when ultramafic rocks such as dunite react with water. These reactions not only transform minerals but also release hydrogen gas as a byproduct. Despite decades of study, however, the details of serpentinization remain poorly understood—particularly in intact rocks where the reactions modify permeability, induce stress, and even deform the rock due to the significant volume increase associated with mineral transformation.
Uncertainty over reaction rates is a major challenge: current estimates of hydrogen generation rates vary by several orders of magnitude, making it difficult to assess the economic viability of geologic hydrogen exploitation. At ERL, our research addresses this problem using a combination of field studies and laboratory experiments. Field outcrops provide a natural record of how serpentinization unfolds over geological time, while controlled experiments allow us to measure reaction rates directly and uncover the mechanisms that govern them.
Together, these approaches shed light on the kinetic and transport processes that regulate hydrogen production. Our findings reveal how permeability feedbacks can sustain serpentinization and generate permeability, offering crucial insights into both natural hydrogen reservoirs and potential engineered systems. By bridging fundamental geoscience with practical applications, we aim to inform the future development of geologic hydrogen as a clean, large-scale energy resource.
Image: Cross polarized image of an experimentally serpentinized dunite core. Large olivine grains are being broken down and transformed to serpentine while liberating hydrogen. Courtesy of Gage Coon.
