Hydrogen storage in a heterogeneous sandstone formation: dimensioning and induced hydraulic effects

Abstract

Large-scale energy storage in the geological subsurface (e.g. by storing hydrogen gas) may help to mitigate effects of a fluctuating energy production arising from the extensive use of renewable energy sources. The applicability of hydrogen (H 2 ) storage in a porous sandstone formation is investigated by defining a usage scenario and a subsequent numerical simulation of a storage operation at an existing anticlinal structure in the North German Basin. A facies modelling approach is used to obtain 25 heterogeneous and realistic parameter sets. The storage operation consists of the initial filling with nitrogen used as cushion gas, the initial filling with H 2 , and six withdrawal periods with successive refilling and shut-in periods. It is found that, on average, the storage can sustain a continuous power output of 245 MW for 1 week when using five storage wells, while peak performance can be as high as 363 MW, indicating that the storage is mainly limited by the achievable extraction rates. The median of the maximum pressure perturbation caused by this storage is around 3 bars and can be observed at a distance of 5 km from the wells.

Sensitivity analysis of gas leakage through a fault zone during subsurface gas storage in porous formations

“…In reality, however, all formations and fault zones show spatial heterogeneity in their petrophysical parameters. A heterogeneous permeability distribution in the storage formation could result in a local increase or decrease of the formation pressure, compared to the homogenous case (Pfeiffer et al, 2017). As shown in this and the previous studies such pressure changes affect the leakage rates occurring in the fault zone.…”

“…In this study, a structural model of a potential storage structure was previously investigated for CO 2 (Hese, 2012) and later for hydrogen storage (Pfeiffer et al, 2017) and is created and used for the scenario simulations. At the storage site, an anticline trap was formed by halokinesis, with normal and reverse faults intersecting with the structure and providing potential leakage pathways for fluid migration (Fig.…”

“…1b). In the previous study by Pfeiffer et al (2017), the faults at the study site are assumed to be sealing and boundary conditions were chosen accordingly for the flow simulation model. Of the three potential storage formations in the NGB, only the Quickborn-Volpriehausen and the Rhaetian sandstones exist at the storage site.…”

“…However, power generation from renewable sources is stochastic, so that the fluctuating availability of wind and solar radiation can cause challenges for an optimal management of energy system and energy storage on various scales might be required in systems largely based on renewable power generation (Schiebahn et al, 2015). The geological subsurface and specifically porous formations can provide large storage capacities for gases (Bauer et al, 2013;Kabuth et al, 2017), either for a mechanical energy storage concept utilising compressed air (Wang and Bauer, 2017;Mouli-Castillo et al, 2019;Sopher et al, 2019) or for storing a chemical energy carrier, such as hydrogen or methane (Sainz-Garcia et al, 2017;Pfeiffer et al, 2017;Matos et al, 2019).…”

“…During a gas storage operation, the storage pressure fluctuates several bars, depending on the current operational mode and storage setup, e.g. up to ±35 bar for a hydrogen storage site designed for weekly withdrawal periods (Pfeiffer et al, 2017) and ±41.5 bar for a compressed air energy storage used in a daily storage scheme (Wang and Bauer, 2017). Studies on gas leakage during natural gas storage show that frequent pressure fluctuations in the storage formation can affect leakage rates through fault zones intersecting the gas storage site (Chen et al, 2013).…”