Hybrid Energy Storage and Hydrogen Supply Based on Aluminum—a Multiservice Case for Electric Mobility and Energy Storage Services

Abstract

The realization of a fully decarbonized mobility and energy system requires the availability of carbon-free electricity and fuels which can be ensured only by cost-efficient and sustainable energy storage technologies. In line with this demand, a techno-economic evaluation of aluminum as a cross-sectoral renewable energy carrier is conducted. The assessment, based on a newly developed process, involves the wet combustion of Aluminum at 700 °C resulting in heat and hydrogen (H2) generation. The designed conversion plant enables the contemporaneous generation of electricity and on demand H2 (up to 4 MW and 46.8 kg h–1) with round-trip efficiencies as high as 40.7% and full recycling of the Al2O3 waste. This study, assuming the carbon-free production of Al and three different energy cost scenarios, proves the feasibility of the e-fueling station business case. The overall energy conversion including fuel production (power-to-Al), utilization (Al-to-power and Al-to-H2), and recycling requires a capital investment of 5200 € per kW installed power without additional primary material demand. Hence, the estimated power-to-X cost for the Al-based H2 is estimated in the range of 4.2–9.6 € kg–1 H2, while wind and solar power based green H2 production cost varies from 6.5 to 12.1 € kg–1 H2.