Rajesh Goteti

Among various options, subsurface storage in salt caverns has emerged as a commercially viable and technically robust solution for large-scale hydrogen storage due to their low permeability, self-healing properties and high operational flexibility. However, the relatively small volumetric capacity of individual caverns compared to other subsurface porous media limits their overall storage efficiency and economic viability. 

Traditionally, hydrogen is stored in salt caverns by injecting compressed gas into the void space. Here we introduce a novel approach to enhance hydrogen storage capacity by filling caverns with microporous sorbent materials prior to gas injection. A range of microporous sorbents—including activated carbons and metal-organic frameworks—were evaluated under representative pressure-temperature conditions. Among them, activated carbon may be the most scalable and cost-effective option for field deployment. The use of commercially available sorbents with favorable cost-performance ratios makes this approach applicable to both existing caverns and new constructions. 

Our experimental results show that microporous materials can significantly increase volumetric hydrogen storage, especially under shallow cavern conditions where gas compression is less effective. When filled with microporous activated carbon, for example, hydrogen storage capacity can be increased by up to 15% when compared to empty caverns. This enhancement offers both economic and operational benefits by maximizing the working gas volume per cavern and reducing capital and operational costs. Additionally, sorbents may provide extra mechanical support, potentially lowering the minimum operational pressure and improving cavern stability during cyclic injection and withdrawal.

This approach represents the first known application of microporous sorbents for enhancing hydrogen storage in engineered salt caverns. It bridges the gap between surface-based hydrogen storage technologies and subsurface geological storage systems. Future research will focus on searching more cost-effective sorbent materials, optimizing the performance of existing sorbents under specific geological settings, evaluating long-term performance under cyclic loading, and conducting field-scale demonstrations to validate the concept.

Co-author/s:

Rajesh Goteti, Geological resources Team Lead, Aramco Americas.

Ahmet Atilgan, Research Scientist, Aramco Americas.

Dr. Yaser Zayer, Lead Geologist, Saudi Aramco.