Hydrogen Paste Meets Reality: Energy In, Energy Out, And What’s Missing - CleanTechnica

The article critically examines Powerpaste, a hydrogen carrier developed by Fraunhofer IFAM that uses magnesium hydride in a paste form to generate hydrogen by reacting with water. This approach aims to address the safety and cost challenges of traditional hydrogen storage methods, such as high-pressure compressed hydrogen and cryogenic liquid hydrogen. Powerpaste offers the advantage of ambient temperature storage and claims higher volumetric energy density than compressed hydrogen, packaged as an easy-to-handle cartridge system. However, the article highlights that the system is not a simple storage medium but a chemical reaction system requiring both the paste and a significant amount of water—about 9 kg per kg of hydrogen produced—making the total input mass roughly 19 kg for 1 kg of hydrogen. When considering the full system—including the fuel cell, reactor, pumps, and other components—the effective energy density drops substantially to about 0.3 to 0.4 kWh per kg, comparable to modern batteries and far below the claims made by Fraun