Ethanol as a Liquid Organic Hydrogen Carrier for Seasonal Microgrid Application: Catalysis, Theory, and Engineering Feasibility

In this work, we describe the benefits and challenges of a green approach to seasonal energy storage using ethanol as a liquid organic hydrogen carrier (LOHC). We evaluate the cycling efficiency of hydrogen release from ethanol (EtOH) to form ethyl acetate (EtOAc) as the spent LOHC and the subsequent regeneration of EtOH from EtOAc catalyzed by a single molecular catalyst, Ru-MACHO, at a moderate pressure of H-2, mild reaction temperature, and high selectivity. From experimental and computational studies, we were able to minimize catalyst deactivation, regenerate the active catalyst post reactions, and establish the energy profile of the deactivation pathway relative to the on-cycle pathway catalyzed by Ru-MACHO. Based upon these findings, we performed a reactor design analysis to determine the footprint of an EtOH-based storage system to provide 85 MWh of energy by storing 5 metric tons (MT) of H-2. We conclude that the heating and cooling required to maintain H-2 partial pressure present a significant engineering challenge for widespread deployment of this system.

Automated summary

The study explores the green approach of using ethanol as a liquid organic hydrogen carrier for energy storage, demonstrating efficient cycling of hydrogen release and regeneration catalyzed by a single molecular catalyst. The research provides insights on minimizing catalyst deactivation and reactor design analysis for an ethanol-based storage system, highlighting the significant engineering challenge posed by maintaining hydrogen partial pressure.