Synergistic Pairing of Intermittent Renewables with Dynamic Aemion®-Based Alkaline Anion-Exchange Membrane Electrolysis
Authors: Britton Benjamin , Baker Andrew M. 
Published: December 2024

The rate-limiting factors of intermittent renewable energy deployment are grid interconnection amounts and timelines, and the storage of this energy. Hydrogen offers a solution to both issues, to the former offering the ability to produce a valuable and presently subsidized resource with direct connection before the interconnect to utilize overcapacity or even replacing an interconnect, and to the latter offering the unique ability to cost-effectively be stored geologically, transported between regions, and repurpose natural gas infrastructure. Global electrolysis capacity is projected to increase to >500 GW in 2030 and in excess of 2500 GW in 2050 (IEA Net Zero 2050).

Buffering capacity with batteries holds some promise but the simplest and most preferred mode of operation would be for electrolysis to follow energy production directly. However, the two established electrolysis technologies suitable to full direct intermittent renewable pairing have limitations to their effectiveness.

Proton-Exchange Membrane Water Electrolysis (PEMWE) are known to exhibits non-linear increases to iridium dissolution while operating greater than 1.6 V, in part due to corrosive environment and in part due to a concentrated volumetric current density resulting in a trade-off of performance and lifetime that limits the economic utility of highly dynamic operation.

Alkaline water electrolyzers do not exhibit the same voltage limitations due to the alkaline environment and the whole-electrode activation of the KOH electrolyte, but the nature of the porous separator itself reduces the ability for fully dynamic operation, in particular managing hydrogen flux in ramp-down.

Alkaline Anion-Exchange Membrane Water Electrolysis (alkaline AEMWE) offers the potential to combine the ability for highly dynamic operation of PEMWE with the larger potential window for electrode stability of AWE to synergistic effect. In essence, the full use of produced energy, lower capital cost of the technology, and ability to trade efficiency for markedly higher production rate results in a lower levelized cost of hydrogen than is achievable with the other technologies. Technology cost-models associated with both direct connection and ‘peaker’ operation will be presented, towards a fuller understanding of the most economically beneficial renewables pairings and operational modes in advance of the expected gigawatt scaling of this technology later this decade.

Further, Alkaline AEMWE Aemion® AF2-HWK8-75-X has been demonstrated in excess of 1 year of operation with some intermittency resulting in no apparent membrane degradation, presenting a baseline for the break-in of commercial electrodes with standard conditions relevant to commercial stacks of 1 M KOH and 70 °C. In this presentation, 1.5 years of data with Aemion® AF3-HWK9-75-X, a next-generation material, and large-area (50 cm²) single-cell data with long-term operation with both NiFeOx and commercial electrodes employing representative modes of intermittency will be shown.