(Energy Technology Division Walter van Schalkwijk Award in Sustainable Energy Technology Address) Low Temperature Water Electrolysis as a Near Term Enabler in Climate Change Mitigation

Abstract

Generating hydrogen from renewable production methods such as water electrolysis is fundamental to meeting decarbonization goals and mitigating climate change. Regardless of the end market split for hydrogen in ground transportation applications, hydrogen is the major feedstock for industrial chemicals such as ammonia and methanol. The only way to make these processes sustainable is to eliminate carbon dioxide emissions from production of the hydrogen feedstock. Currently, over 95% of this hydrogen is generated from natural gas and other fossil fuels, producing roughly 9 g CO2/g H2. A combination of technologies such as natural gas reforming with carbon capture, utilization and sequestration (CCUS) and water splitting via electrolysis therefore need to be deployed as quickly as possible. In addition, any scheme to convert carbon dioxide to useful chemicals requires a renewable source of hydrogen atoms. So to address both curtailment of ongoing emissions and mitigation of existing CO2 waste streams, renewable hydrogen is a lynchpin for success.Low temperature electrolysis has commercially deployed for decades, making it one of the only water splitting technologies likely to make an impact in the next 5-10 years. Both liquid alkaline electrolyzers (or alkaline water electrolyzers, AWE) and proton exchange membrane water electrolyzers (PEMWE) have been deployed at >10 MW scale, and many companies are actively working to scale manufacturing to gigawatt capacity. While 2050 goals will likely involve implementation of a broader portfolio of technologies, scaling deployment of existing carbon neutral hydrogen technologies provides the greatest long term benefit by reducing overall emissions earlier. We therefore cannot let “perfect [become] the enemy of good”[1] in terms of waiting for the most efficient, lowest cost solution. At the same time, there are significant improvements that can be made in both AWE and PEMWE products, through advanced materials, processes, and automation. The PEMWE technology in particular can leverage much of the investment in PEM fuel cell research and development, although understanding of electrolysis specific materials and processes in ongoing. This talk will focus on the relationships between material research, process development, and understanding of degradation mechanisms in commercializing reliable technology, and the importance of academia, national labs, and industry to work together in this effort. [1] Commonly attributed to Voltaire, and others.