As researchers continue innovating energy storage methods and efficiency, underground — or subsurface — storage is emerging as a possible answer to industry challenges.
From storing new fuel sources like hydrogen to capturing and storing carbon emissions, Texas A&M University researchers are pursuing solutions that could lie right beneath our feet.
However, injecting gases into the subsurface presents unique challenges for scientists to consider — specifically, ensuring the gases remain securely contained over time.
Two separate teams, including researchers from the Harold Vance Department of Petroleum Engineering, have secured funding to help further research in these areas through seed grants provided by Texas A&M University’s Targeted Proposal Teams (TPT) program.
Started in 2024, the TPT initiative aims to foster innovative research that addresses major challenges in food and resource scarcity, health and quality of life, energy, national security, and other areas. Through interdisciplinary collaboration, the grants support projects in their early stages that could lead to critical discoveries in areas of urgent need.
Both projects highlight Texas A&M’s commitment to support research that drives solutions for real-world impacts.
Underground hydrogen storage
The project, “Quantifying the Impact of Biofilm Formation on Underground Hydrogen Storage,” is led by petroleum engineering's Dr. Rita Esuru Okoroafor and civil and environmental engineering's Dr. Yinou Yao.
Hydrogen is emerging as a key source of renewable energy as researchers explore alternative fuel sources. Underground hydrogen storage — the process of injecting hydrogen into the Earth’s subsurface — is a promising solution to safely stockpiling large amounts of hydrogen.
This practice brings a unique set of challenges that researchers are working to understand and address. These include preventing hydrogen from leaking out of storage, preventing contamination and even worrying about what subsurface microbes might snack on the hydrogen stored underground. Enter researchers like Okoroafor and Yao.
“We know that there are some microbes that can consume hydrogen as a source of food,” Okoroafor said. “When they converge on the hydrogen, they create biofilms that fill the pores in rocks. What we are trying to figure out with this project is the effect that these microbes have on our ability to store hydrogen. Will they help or hinder?”
The presence of these microbes is not necessarily negative. In fact, in seal rocks (layers that prevent hydrogen from leaking), they could be beneficial in helping to contain the hydrogen. But if they clog the pore spaces in reservoir rocks, it could potentially cause a decrease in hydrogen flow and impact the ability to recover stored hydrogen.
To investigate these effects, Okoroafor and Yao are conducting laboratory experiments using carefully selected microbes under controlled conditions, such as specific temperatures and hydrogen injection rates. They are expected to analyze the results from their experiments this fall.
Geologic energy storage
Drs. Kiseok Kim and Rami Younis, both from the petroleum engineering department, lead the project, “Engineered Geo-Barriers for Geologic Energy Storage," which seeks to understand how we can create sealed storage areas in the subsurface.
It’s vital to ensure that liquids stored in the ground — such as hydrogen, carbon dioxide and wastewater — stay where we put them. Improper storage of these fluids could leak or migrate to unwanted areas, potentially contaminating aquifers or escaping into the atmosphere.
“To mitigate any negative effects of injecting these fluids into the ground, we have encountered a new engineering challenge: how do we create compartmentalization underground? How can we make silos within vast geologic formations when they aren’t naturally there? So in answer, we have come up with a concept to do that,” Younis said.
Their solution is to use targeted chemical precipitation to build impermeable flow barriers inside rock formations.
The method, which will be further developed with funding from the TPT program, involves injecting two separate fluid streams — one of sulfate ions and the other of barium — into the subsurface. When the two streams meet at a potential leak site, the barium and sulfate ions would mix to form a new mineral, barite.
“The barite acts as a seal for the leak, creating what we call a flow barrier,” Kim said. “With this method, we could essentially create natural underground storage tanks.”