Reactive Metals as Energy Carriers: An Aluminum-based Hybrid Energy Storage Case

Rapid acceleration on decarbonization of the major emitting sectors (i.e., energy generation, transportation) becomes more emergent to reach CO2 mitigation targets. In this
sense, installation of renewable energy technologies and ensuring its continuous availability are crucial aspect for the emission reduction. To maintain this, availability of storage technologies and renewable fuels must be ensured. Mainly, Power-to-X technologies enable he balance of generation using different energy vectors (chemicals, heat, gas, etc.). In that sense, hydrogen (H2) is considered the main electricity-based fuel due to its large specific energy density. Nevertheless, techno-economic obstacles disabling its massive utilization necessitates the introduction of alternative energy carriers to meet the demand. For the very reason, metal energy carriers become very interesting alternatives for supporting this demand as they are energy dense heat and H2 carriers Especially, metals like aluminium (Al), iron (Fe), sodium (Na)
considering their wide availability. Thus, in this study an Al wet combustion plant and use case is presented for contemporaneous electricity (4 MWe) and H2 (up to 46.8 kg h-1) supply aiming the mobility sector demand management and grid services. ... mehrThe proposed concept is a circular metal system where combusted Al is returned to the producers as Al2O3 and
the round-trip efficiency of the system reaches up to 40.7% assuming a carbon-free Al smelting process. As for the economics, competitive electricity and H2 costs are estimated
with respect to other energy carriers. Especially, the Al-based H2 cost which is in the range of 4.2–9.6 € kg–1 H2 as discussed in detail.