Hard as a rock, LLNL to study geologic hydrogen production

Lawrence Livermore National Laboratory (LLNL) has received $1 million to explore technologies that stimulate hydrogen production from mineral deposits found in the subsurface, including developing our understanding of hydrogen-producing geochemical reactions and how to enhance or control the rate of hydrogen production.

The use of hydrogen fuel to offset fossil fuel applications could assist efforts to reduce climate change impacts if it can be produced via methods that do not intensify greenhouse gas emissions (GHG) and climate impacts.

“Geologic hydrogen production is one alternative to current hydrogen production methods that could offer from lower to no GHG emissions and potentially lower costs, given the vast subsurface resources of magnesium and iron- bearing minerals,” said LLNL principal investigator Maria Gabriela Davila Ordonez.

LLNL is among 16 projects across eight states, funded through two DOE Advanced Research Projects Agency-Energy (ARPA-E) Exploratory Topics, to accelerate the natural subsurface generation of hydrogen. This energy resource would potentially produce no carbon emissions when burned or used in a fuel cell and will support efforts to reduce costs and enable commercial-scale deployment of clean hydrogen.

The LLNL project specifically will increase the rate of hydrogen generation from olivine and olivine-bearing rock assemblages using short-chain organic acids as chemical stimulants. Davila Ordonez said both technologies have cost and GHG offset benefits; the challenge lies in delineating their applicability to subsurface reserves of variable quality and at different locations. The team will assess short-chain organic acids for their ability to further stimulate mineral breakdown and subsequent iron oxidation and coupled hydrogen production.

“The benefits of using organic acids are twofold: hydrogen production and recovering rare earth minerals and other critical materials of interest that help offset the costs of implementing this technology at large scale,” Davila Ordonez said.

The technology can be applied above-ground to mined rock and wastes, or potentially in situ at depth, pending selection of durable, low-cost acids. For both technologies, real-time monitoring of hydrogen production rates will help optimize performance. Ultimately, Davilla Ordonez said the project results will allow for recommendations for site selection, plant design and technology implementation for production of low-cost hydrogen.