PEM Electrolysis: Ready for Impact

Abstract

The need for energy storage has never been so pressing; due to the increased proliferation and intermittent nature of wind and solar power sources, many regional grids can no longer accept more of these sources. Electrolysis of water using polymer electrolyte membranes (PEMs) has long held the promise of large-scale energy storage, needing only the simplest of reactants, water. The adoption of PEM electrolyzers has been impeded due to the headwinds of high capital cost, poor efficiency, and unknown reliability. Numerous incremental improvements, and increasing economies of scale over the past 10 years have led to very large decreases in the cost of PEM electrolysis. Increasing operating temperature has had the largest impact on efficiency and output. Subsequently, whereas only a few years ago there were no commercial PEM electrolyzer stacks in the 1 MW range, today at least five companies are at or near launch of MW electrolyzer systems.