FROM HYDROGEN STORAGE TO FUEL CELLS: HYDROGEN DISCHARGE AS THE NEXT BOTTLENECK

Abstract

Engineering advances have enabled a wide range of technologies for hydrogen generation and storage. Although hydrogen storage remains challenging in many cases, the controlled discharge of stored hydrogen to conditions suitable for fuel cell operation has emerged as the next system-level bottleneck. Here, the underexplored constraint falls on the large deviation between the hydrogen storage conditions and the operating requirement of fuel cells. In particular, hydrogen need to be supplied to fuel cells in the gas phase at near-ambient pressure (~0.5 MPa) and temperature (~353 K). These conditions are not fully aligned with any of the existing storage forms, including compressed gas, cryogenic liquid, or solid-state storage. Such mismatches lead to heat losses, increased capital investment, flow-rate fluctuations, system-level inefficiencies, and safety concerns. Thus, the next key question in advancing hydrogen energy is how to enable stable and controlled hydrogen release from the three storage forms into fuel cells for desired electricity generation. This paper presents perspective on directions in this area for future research and development.