Comparative techno-economic assessment of stationary hydrogen storage technologies

This study presents a techno-economic assessment of hydrogen storage technologies within complete power-to-hydrogen plants supplying steady industrial hydrogen demand at four different geographical locations—Hajira (India), Bari (Italy), Bremen (Germany), and Houston (USA). Optional grid electricity is permitted subject to each site's green-hydrogen Greenhouse-Gas (GHG) limit. Three storage classes are evaluated: compressed-gas tanks (Types I–IV), underground hydrogen storage, and Metal Hydrides (MH). For MH, configurations both with and without phase-change materials as heat storage devices are modeled, using heat supplied from either recovered industrial waste or from electric heaters. Performance metrics comprise Levelized Cost of Hydrogen (LCOH), levelized cost of storage, storage CAPEX, OPEX, footprint, and installed mass. Results show that in some locations the GHG intensity limit can become the binding constraint; in Hajira, low electricity prices would otherwise favor greater grid reliance, but the high grid emission factor hinders further reductions in LCOH. Underground hydrogen storage (salt cavern) achieves everywhere the lowest LCOH where suitable geology and access exist; among tanks, low-pressure Type I is most cost-effective, while higher-pressure Types II–IV impose a 0.3–0.6 €/kg LCOH penalty. Under tight mass-footprint constraints, Types III–IV are preferred, trading modest cost for compactness. For MH, MgH2 with waste-heat supply is competitive, whereas electrically heated MH — especially MgH2 — is least competitive.