ABSTRACT
Proton exchange membrane (PEM) electrolyzers were originally developed for oxygen generation and compression for military applications, such as onboard breathing support on aircraft (Harrison 1975) and nuclear submarines (Carlson et al. 2000). In these applications, system operation reliability is critical. The components and system design are focused on reliability, not necessarily on the cost. The commercial application of PEM electrolyzers started as the cylinder replacement of high-purity hydrogen in gas chromatographs and electrical generator cooling gas (Coker et al. 1982) to eliminate the gas-handling cost. Since then, technology developments have continuously reduced PEM electrolyzer costs, which enabled the use of PEM electrolyzers in various commercial applications. The most significant development in recent years is the “power to gas” program supported by the German government to generate hydrogen from the underutilized electricity from renewable sources like photovoltaics and wind turbines (Christopher 2013; Weinmann 2012). The hydrogen generated from an electrolyzer can be stored in natural gas pipeline, salt caverns or used as industrial feeds. However, it has been recognized that the capital investment and the operation cost of the current electrolyzer technology are still too high for “power to gas” application (Colella et al. 2014). Recent technology developments are focused on cost reduction to meet the application requirement.
