Kilowatt hours of electricity needed to produce 1kg of hydrogen?

Answer 1

1 watt is a unit of power (energy/time used) therefore 1 watt = 1 joule of Energy/second.


Kilowatt-hours are energies calculated from (1000 joules/sec)x3600 seconds of an hour time=3.6 million joules = 3.6 Megajoules of Energy to be delivered to produce, for instance, hydrogen.

To decompose 1 mole of water, 0.018 Kg. of water, you need to supply an amount of charge of 96,500 coulombs, giving 0.016 Kg. of Oxygen ans 0.002 Kg. of hydrogen.

You need then to provide 500 times 96,500 coulombs to get 1 Kg of hydrogen , (notice that 1,000/0.002 = 500). Notice that 500 =1,000/2.

You require then (1,000/2) times 96,500 coulombs of charge in order to be able to get 1 Kg of Hydrogen from ENOUGH water at your vessel. That is, (1,000/2) times 96,500 coulombs = 96.5 /2 Megacoulombs, because Mega in Greek is equivalent to Million in English.

You need then 48.25 Megacoulombs of charge, because 96.5/2 =48.25 if you are going to recuperate 1 Kg. of gas hydrogen . These charges represent an amount of electrical energy , to be measured in joules of energy, you have to provide to do your wish.
-19
Each carge represents as an entity storing 1.6 times 10 coulombs. 1 mole
23 -19
equivalent of electrons represents 6.06 times 10 times (1.6 times 10 coulombs)
4
or about slightly more than 9.6 times 10 coulombs = 0.0096 Megacoulombs


(Will continue, dated 15 October 2009).