Hydrogen storage in depleted subsurface reservoirs

August 21st, 2023

R&D Focus Areas:
Underground storage

Lead Organisation:
University of Western Australia

Future Energy Exports CRC


Start date:
March 2023

Project summary description:
Burning fossil fuels has led to the emission of greenhouse gases into the air, contributing to global warming by trapping heat in the atmosphere. As a result, the demand for renewable energy generation has increased in order to reduce global warming, prevent climate change, and meet the 2050 Paris Agreement. However, renewable energy generation is weather-dependent (e.g., wind force and intensity of sunlight), making it unreliable and resulting in a gap between supply and demand.

An appropriate solution is converting excess electrical energy to produce green hydrogen via electrolysis, which can be temporarily stored in subsurface geological formations and extracted to fulfil energy demand when needed. This is known as Underground Hydrogen Storage, which has gained a lot of popularity as a solution to store renewable energy. Underground hydrogen storage requires a cushion gas (N2, CH4 or CO2) prior to the injection of hydrogen; its role is to pre-pressurize the system, aiding with the withdrawal and injection of hydrogen. These gases/fluids are, however, fully soluble with hydrogen, and thus sufficient mixing can undesirably contaminate the extracted hydrogen product.

The impact of the permanently stored cushion gas on the injected hydrogen is unknown, and the quantitative extent of mixing between them in the porous medium is uncertain. Fluid mixing in a porous medium is typically characterized by a dispersion coefficient (KL).

The aim of this research is to measure KL for H2-CO2, H2-N2, and H2-CH4 mixtures at reservoir conditions. These results will contribute to a more comprehensive understanding of fluid mixing in porous media and will aid in the development of accurate reservoir simulations for underground hydrogen storage.

Further information:
23.RP2.0164 Hydrogen storage in depleted subsurface reservoirs – Future Energy Exports CRC (www.fenex.org.au)


Reviewed: August 2023