1. Optimizing underground hydrogen storage in aquifers: The impact of cushion gas type.
- Author
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Saeed, Motaz and Jadhawar, Prashant
- Subjects
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UNDERGROUND storage , *HYDROGEN storage , *AQUIFERS , *GASES , *CARBON dioxide - Abstract
This study investigated the impact of cushion gas type and presence on the performance of underground hydrogen storage (UHS) in an offshore North Sea aquifer. Using numerical simulation, the relationship between cushion gas type and UHS performance was comprehensively evaluated, providing valuable insights for designing an efficient UHS project delivery. Results indicated that cushion gas type can significantly impact the process's recovery efficiency and hydrogen purity. CO 2 was found to have the highest storage capacity, while lighter gases like N 2 and CH 4 exhibited better recovery efficiency. Utilising CH 4 as a cushion gas can lead to a higher recovery efficiency of 80%. It was also determined that utilising either of these cushion gases was always more beneficial than hydrogen storage alone, leading to an incremental hydrogen recovery up to 7%. Additionally, hydrogen purity degraded as each cycle progressed, but improved over time. This study contributes to a better understanding of factors affecting UHS performance and can inform the selection of cushion gas type and optimal operational strategies. • Compositional numerical simulation of underground hydrogen storage in a North Sea aquifer utilising CMG-GEM. • Hydrogen recovery efficiency improves with the utilisation of cushion gas. • CO 2 exhibits highest storage capacity; N 2 and CH 4 improve recovery efficiency. • CH 4 as cushion gas leads to 80% recovery efficiency, minimizing lateral spreading and viscous fingering. • Cushion gas density dictates the efficiency of the underground hydrogen storage scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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