HyFive : Practical Techno‐Economics and Valuation Framework for Geological Storage of Hydrogen

ABSTRACT HyFive is a modular techno‐economic framework for underground hydrogen storage that runs in a single pass from geological and engineering inputs to a levelized cost: user‐specified design parameters (well geometry, depth, storage volume, cushion gas fraction, compression duty, cycling frequency) drive cost modules whose CAPEX and OPEX streams enter a discounted cash‐flow model returning net present value and levelized cost (LCOS). A financial valuation layer is coupled directly to the engineering cost build‐up, so a design change propagates to a levelized cost without a separate reconciliation step. Salt cavern and porous media modules carry their own engineering design and cost assumptions but share one financing basis, making the two lithologies directly comparable. Seven scenarios span both geological formations and a range of storage capacities: cases within the same formation isolate the effect of scale, while cases matched in capacity across formations isolate the effect of geology. Large domal salt caverns are cheapest, at $0.56/kg for 5500 MMcf, against $1.45/kg for 7000 MMcf porous media. At 1000 MMcf the comparison reverses: the porous media case costs roughly half the capital of the bedded salt case ($14.9 M vs. $30.4 M) and is about 17% cheaper over the project life ($0.90/kg vs. $1.09/kg). Across the porous media pair, LCOS rises instead of falling with capacity, because it uses seven wells instead of one. This is specific to well‐count scaling, not a general claim about porous media economics; other designs could reverse it.