Given recent interest in the discovery of naturally accumulating deposits of subsurface hydrogen known as geologic hydrogen (earlier post), the US Department of Energy (DOE) announced up to $20 million in funding to develop technologies that can stimulate the generation of hydrogen within the subsurface at the lowest cost and environmental impact.

The subsurface continuously generates and consumes hydrogen through natural geochemical and biological processes. There has been recent interest in the discovery of naturally accumulating deposits of subsurface hydrogen, such as efforts by the United States Geologic Survey (USGS). Estimates vary from as little as 500,000 tonnes/year to as much as billions of tonnes/year of hydrogen being produced in the subsurface and accumulating in areas where mineralogical production processes are faster than consumptive biological processes.

While the supply of naturally accumulating hydrogen, in and of itself, is potentially impactful on the U.S. energy economy, iron in the earth’s crust has the theoretical potential to produce around 150,000 Gt H₂ from the reaction of Fe(II) within 3 km of the surface. Exploiting a small percentage of this source through stimulated mineralogical processes could yield larger quantities of hydrogen than what are produced naturally.

For reference, 1 Gt H₂ has enough energy to power the entire U.S. for a year. Thus, engineering the production of subsurface hydrogen could potentially enable the production of substantial amounts of clean energy.

—DE-FOA-0002784 Modification 7

ARPA-E supports transformational, impactful energy technologies. So, when it comes to geologic hydrogen, we’re asking ‘are there disruptive ways to access this hydrogen source and explore the potential?’. There is significant opportunity to accelerate the development of hydrogen production, and I look forward to the teams pursuing this exploration.

—ARPA-E Director Evelyn N. Wang

While the supply of naturally accumulating hydrogen, in and of itself, can enhance the US energy economy, reduced iron minerals within the Earth’s crust have the theoretical potential to produce even more hydrogen from reactions within the subsurface. Using stimulated mineralogical processes could yield larger quantities of hydrogen than what are produced naturally. Thus, engineering the production of subsurface hydrogen could be a substantial source of clean energy.

The funding announced today is part of two Advanced Research Projects Agency-Energy (ARPA-E) Exploratory Topics. (DE-FOA-0002784 Modification 7) The first—Exploratory Topic G: Production of Geologic Hydrogen Through Stimulated Mineralogical Processes—seeks technologies that stimulate hydrogen production from mineral deposits found in the subsurface, including developing the understanding of hydrogen-producing geochemical reactions and how to enhance or control the rate of hydrogen production.

The second—Exploratory Topic H: Subsurface Engineering for Hydrogen Reservoir Management—focuses on technologies relevant to the extraction of geologic hydrogen, including improvements in subsurface transport methods and engineered containment, reservoir monitoring and/or modeling during production and extraction, as well as assessing the risk of hydrogen reservoir development.

ARPA-E targets for geologic hydrogen production for this effort.