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<\/figure>\n\n\n\nThis is easy to understand, because energy losses usually increase more than linearly with current density: to obtain the same average current density, the lower energy losses at lower-than-average current are more than offset by the higher energy losses during periods of higher-than-average current.<\/p>\n\n\n\n
There are a few noteworthy exceptions: for example, at low currents, the stack losses can decrease with increasing current density due to shunt currents. Also, by modulating at the time scale of gas build-up, a small advantage may be obtained. Finally, there may be a regime at extremely high frequencies at which the catalysis will be influenced. However, in general, claims of improvement should be considered with healthy scepticism.<\/p>\n\n\n\n
For a cell voltage V0<\/sub>+ARj<\/em>, the larger the difference between the high current (j<\/em>high<\/sub>) and low current (j<\/em>high<\/sub>), and the larger the fraction of the time D<\/em> or 1-D<\/em> that the current is high or low, the higher the specific energy consumption (SEC) compared to DC (j<\/em>av<\/sub>) :<\/p>\n\n\n\n This prediction was nicely validated by in-house experiments with an AEM cell.<\/p>\n\n\n\n Anamika Ghosh, J.W. Haverkort, Modulating the current in water electrolysis does not increase energy efficiency compared to a constant equal average current, International Journal of Hydrogen Energy, Volume 221, 2026, 154195<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" An often mentioned simple way to improve water electrolysis is to modulate the current, for example, by rapidly switching it on and off periodically. Many papers report improvements without a fair comparison with the non-modulated (DC) case. In such a … Continue reading ![\"\"](\"https:\/\/jwhaverkort.weblog.tudelft.nl\/files\/2026\/03\/image-1.png\")
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