Hydrogen is expected to play a key role in future decarbonized energy systems. It is typically considered that in such systems, hydrogen would need to be synthesized in some way; for instance, by the electrolysis of water. However, hydrogen also exists naturally in subsurface geologic accumulations, suggesting another source of the gas. Although naturally-occurring hydrogen has been found in various locations across the globe, it has not yet been commercially developed at scale. Moreover, it is not yet clear how much natural hydrogen there is or if it could be extracted and processed in a low-carbon fashion. Now, Adam Brandt at Stanford University addresses this latter issue by performing an analysis that aims to provide an initial estimate of the greenhouse gas intensity of natural hydrogen.
In his analysis, Brandt makes use of a modified version of an open-source oil and gas life-cycle assessment tool. This enables him to explore how parameters such as gas composition, well depth and productivity, waste gas handling and source of energy to power production processes influence the emissions associated with the production of natural hydrogen. In particular, the results are sensitive to the nature and proportion of the gases in the accumulation: a high hydrogen fraction, balanced with inert gases, is preferable. Brandt suggests that under reasonable assumptions it should be possible to extract natural hydrogen with low greenhouse gas intensity, but also stresses that the analysis is not intended to definitively determine its environmental impact, but rather to act as an early-stage assessment to help guide future development and investment.
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