Texas Geologists: Salty About the Energy Transition

Cody Good
Salt dome cartoon
A salt dome pictured courtesy of John Perez Graphics

After reaching peak fame in 2017 at hands of Salt Bae, salt is making its comeback, but this time because of geologists.

What happened: Researchers from the Bureau of Economic Geology at the University of Texas at Austin released a paper highlighting the key role underground salt can play in energy transition technologies, including hydrogen, carbon storage, and geothermal energy.

Salt is not like a regular mineral, it’s a cool mineral

Relative to other minerals salt is squishy, low density, a barrier to fluid flow, and a great heat conductor.

Physically, it can be thought of like playdoh: squish it and it’ll flow upwards out of your fist. Compress in underground rock layers and it’ll flow upwards into irregular shapes called salt domes.

  • These underground salt layers can form salt domes larger than Mount Everest.

Storing with salt: The researchers emphasized that the decades of research and industry expertise spent understanding these salts can be applied to storing hydrogen for near-term use or permanently for carbon dioxide.

  • Salt already has a proven track record of fluid traps, including the US Strategic Petroleum Reserve that stores the country’s emergency supply of oil.

But rather than war-time fuel reserves, the paper highlights how similar caverns could be used to store energy generated by renewables underground as hydrogen storage, balancing the intermittent supply and demand.

Hot salt rocks, but not too hot: Salt could also play a role in geothermal energy which is traditionally most economic in volcanic regions where it’s hot at shallow depths. Fortunate for us but unfortunate for geothermal developers, the world’s not volcanically active everywhere.

Rather than drilling deep down to hotter zones, heat channels upwards through the salt could open up more areas for economic geothermal development using salt’s unique heat conduction.

Big picture: We can all appreciate papers such as this which gather the collective scientific knowledge on a subject that aids the energy transition. It’s another lesson that all the knowledge and technology gained from oil and gas can continue to be used in the future.