Question

Explain clearly why the hydrogen economy has not taken-off, even though hydrogen has 3-times more energy per gram than gasoline?

Answer 1

Answer:

We can explain the difficulty of the Hydrogen economy with few reasons, those are,

• Hydrogen is not very dense, even in liquid state (that means liquid hydrogen) it has a density of only 0.071 grams per cc, a factor of 10 times less than gasoline.
• Hydrogen has 3-times more energy per gram than gasoline, then we find that hydrogen stores only 0.071 x 3 = 0.21 times as much energy per cc (or per gallon) as gasoline.This is a factor of 3 times worse, since hydrogen can be used more efficiently than gasoline.
• Compared to gasoline, liquid hydrogen has 3 x times more energy per gram (or per lb) but 3 x less energy per gallon (or per liter).
• Simply we can say that 1 kilogram of hydrogen $\approx$ 1 gallon of gasoline
• Hydrogen liquid is dangerous to store since it expands by a factor of thousand if warmed. We need to protect with a thick-walled tank and stored as a high-pressure gas. Compared to gasoline compressed gas hydrogen has 6 x less energy per gallon (or per liter).