4 ms·

Edit: someone more knowledgable responded with more accurate numbers about energy conversion- read their comment. This still seems like it would only make sens

Edit: someone more knowledgable responded with more accurate numbers about energy conversion- read their comment. This still seems like it would only make sense when there is an energy surplus (e.g. excess solar generation) and it is useful to store energy in this form rather than a battery.

philipkglass 2y ago
You are right that this makes sense to store an energy surplus. The reason you see such a large gap between "41.5 kWh/kg" and "33.6 kWh/kg" is that the latter value refers to what is called the lower heating value (LHV) [1]. The higher heating value (HHV) of hydrogen is 39.4 kWh/kg, and that's where the 95% efficiency claim comes from: 39.4 / 41.5 = 94.9%. This has a good explanation of higher and lower heating values for chemical fuels: https://en.wikipedia.org/wiki/Heat_of_combustion#Higher_heating_value https://en.wikipedia.org/wiki/Heat_of_combustion#Higher_heat... [1] https://en.wikipedia.org/wiki/Energy_density#In_chemical_reactions_(oxidation) https://en.wikipedia.org/wiki/Energy_density#In_chemical_rea...