# Skepticism on new hydrogen production process

Newswire reports on a Korean claim that they can produce hydrogen from water vapor dramatically more efficiently than current processes:
He said "Our laboratory tests show that CO2, CH4, or N2O was dissociated by low energy. We also confirmed that hydrogen (H2) and vapor(H2O) was dissociated with similar efficiency (90% or more). Traditionally hydrogen is made by electrolysis. The electrolytic method uses 4-4.5 kwh energy for getting 1 cubic meter of hydrogen. Our method uses 0.1 kwh for the same volume of hydrogen. As known the high cost of electrolytic H2 does not allow to use it as a fuel.

I'm skeptical of this for two reasons. First, the standard method of hydrogen production isn't electrolysis, it's "steam reforming", which Wikipedia claims has an 80% efficiency. Second, the efficiency of electrolysis appears to hover around 50% (wikipedia again).Given this, it's hard to see how you can get an improvement of over an order of magnitude.

Even if we ignore these issues, the energetics seem problematic. The formation of H20 (gas) via the reaction of oxygen and hydrogen produces around 240 kJ of heat/mole of hydrogen. Running the reaction in reverse, we expect to consume around 240 kJ of energy/mole of H2, which gives us the thermodynamic limit for the amount of energy required to produce hydrogen from water. The article quotes .1 kwh/cubic meter of hydrogen. Assuming that's at STP, then that's about 50 moles of hydrogen (a mole of gas has a volume of about is 20 liters). So, if we divide by 50, we get .002 kwh/of hydrogen per mole. 1 kwh is 3.6x10^6 J, so if we multiply out (.002*3.6x10^6) we get an energy input of 7.2x10^3 J (7.2 kJ). So, unless I've totally forgotten my thermodynamics or I've screwed up my math somewhere (both are possible, I suppose), then I don't see how this result can be correct.

Maybe their "energy use" is "net energy use", i.e. "energy for separation minus energy output"? That would still be impressive, though, so I'll second your "false alarm" guess.