Hydrogen storage in porous geological formations is a potential option to mitigate offsets between power demand and generation in an energy system largely based on renewables. Incorporating hydrogen storage into the energy network requires considering multiple scenarios for storage settings and potential loading cycles, causing a high computational effort. Therefore, homogenous replacement models are constructed by applying different spatial averaging methods for permeability and linearized relative permeability to an ensemble of heterogeneous reservoir representations of a potential hydrogen storage site. The applicability of these replacement models for approximating storage characteristics like well flow rates, pressure changes and power rates is investigated by comparing their results to the results of the full heterogeneous ensemble. It is found that using the arithmetic mean to estimate the lateral and the harmonic mean for the vertical permeability in the homogeneous replacement models provides an approximation to the median of the heterogeneous ensemble for pressure changes, storage flow rate, gas in place and power output. Basic time depended effects of reducing well flow and thus power rates during an extraction cycle can also be represented by these homogeneous replacement models. Using geometric means is found not to yields a valid representation of the storage behaviour.

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