At last spring’s National Hydrogen Association (NHA) conference, graduate research assistant Andrea Allen reported on the performance and efficiency of our hydrogen fueling station over its first full year of operation. During the conference, SERC director Peter Lehman and Andrea discussed the efficiency of the electrolyzer with representatives from Proton Energy Systems, the unit’s manufacturer. With the desire to field test their new product, Proton offered to replace the current electrolyzer cell stack with a newer developmental model, designed for higher efficiency and lower cost. This new cell stack uses a bipolar plate design with a 70% part count reduction. Fewer parts result in an overall reduction in the interfacial resistances of the cell stack, which leads to better performance. In addition to replacing the electrolyzer cell stack, Proton recommended installing a valve to partially bypass the heat exchanger, allowing the electrolyzer to run at a higher temperature, which further increases the efficiency.