A new study led by researchers at The University of Texas at Austin’s Bureau of Economic Geology describes how large underground salt deposits could serve as hydrogen holding tanks, conduct heat to geothermal plants, and influence CO2 storage.
Published in the journal Tektonika, the paper also highlights how industries with existing salt expertise, such as solution mining, salt mining, and oil and gas exploration, could help make this regular ingredient a key component in the energy transition.
“We see potential in applying knowledge and data gained from many decades of research, hydrocarbon exploration, and mining in salt basins to energy transition technologies,” lead author Oliver Duffy said in a media statement. “Ultimately, a deeper understanding of how salt behaves will help us optimize design, reduce risk, and improve the efficiency of a range of energy transition technologies.”
Duffy pointed out that salt has an influential role in shaping the earth’s subsurface layers. It is easily squeezed by geologic forces into complex and massive deposits, with some subsurface salt structures taller than Mount Everest. These structures and their surrounding geology offer a number of opportunities for energy development and emissions management.
“The co-location of surface infrastructure, renewable energy potential, favourable subsurface conditions and proximity to markets are key to plan for subsurface hydrogen storage,” said study co-author Lorena Moscardelli, director of the bureau’s State of Texas Advanced Resource Recovery (STARR) program. “STARR is currently engaged with emerging energy opportunities in West Texas that involve hydrogen and carbon capture, utilization and storage potential for the region.”
Salt domes are proven containers for hydrogen used by oil refineries and the petrochemical industry. According to the paper, these salt formations could also be put to use as holding pens for hydrogen bound for energy production. Moreover, the porous rock surrounding them could be used as a permanent storage spot for CO2 emissions.
The study describes the potential benefits of co-locating hydrogen production from natural gas called “blue hydrogen” and CO2 storage. While the hydrogen is sent to salt caverns, the CO2 emissions generated by production could be kept from the atmosphere by diverting them to the surrounding rock for permanent storage.
According to the researchers, with its numerous salt domes surrounded by porous sedimentary rock, the Texas Gulf Coast is particularly well suited for this type of combined production and storage.
The study also touches on how salt can aid in the adoption of next-generation geothermal technology. Although the industry is still in its early stages, the scientists show how it can make use of salt’s ability to easily conduct heat from warmer underlying rocks to produce geothermal power.
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