I agree about the significance, but I don’t believe that hydrogen will ever be a significant private transportation fuel. Instead, it will be a feedstock for synthesis of hydrocarbon fuel very similar to what we use today. The other inputs will be energy and a carbon source, which might be CO2 extracted from the air or industrial processes.
What follows is something I wrote back in May about hydrogen as a transportable vehicle fuel.
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Hydrogen is perhaps the most difficult stuff to store and transport in existence (except for highly radioactive stuff) because of its immutable physical characteristics.
It cannot be liquified at any reasonable temperature (or cost) for general use, and cannot be solidified. It will form an explosive mixture in air over the widest concentration range of almost every other gas, making it extremely dangerous in closed areas.
As a metal (electron donor) it penetrates and dissolves (embrittles) metal tanks and pipes. As the physically lightest molecule, it has the highest average velocity, and diffuses through any flaw or weakness in containment. And an indicator gas, such as is added to natural gas to warn of leaks, would not penetrate the same flaws to provide such a warning.
1. Petroleum hydrocarbons are the second most abundant source of hydrogen on Earth, after the oceans.
2. Gasoline is a mixture of hydrocarbons - chemically similar molecules, all with a straight or branched chain of carbon atoms, plus a number of attached hydrogen atoms. Collectively, all can be represented by the generic formula:
H - (CH2)n - H
where n can be any number up to perhaps 40 or so. The lightest is Methane (CH4), the major component of natural gas. Carbon has an atomic weight of 12 and Hydrogen 1, so Methane has a molecular weight of 12 + 4 = 16, 25% of which (by weight) is Hydrogen.
3. Propane, which can be liquefied at ambient temperatures and relatively low pressure, is C3H8, with a molecular weight of 12 x 3 + 8 = 44, and is 18% Hydrogen by weight. This light hydrocarbon is produced as a byproduct of petroleum refining.
4. Gasoline is a mixture of medium weight liquid hydrocarbons, but can reasonably be represented (on average) by Octane, C8H18, which has a molecular weight of 8 x 12 + 18 = 114, and is 15.8% Hydrogen by weight.
5. One mole of Hydrogen gas at Standard Temperature and Pressure (STP = 68F, 14.7PSI) has a volume of 22.4 liters (5.92 gallons) and weighs 2 grams. Liquid Hydrogen has a specific gravity of 0.070. This means 1 liter would weigh 70 grams, and 22.4 liters would weigh 1568 grams.
6. 5.92 (we will use 6) gallons of gasoline would weigh approximately 6 x 8 x .75 = 36 pounds, x 16 oz/lb x 25.4 grams/oz = 14,360 grams. 14,360 x .158 = 2269 grams of Hydrogen, in the same space, without compression.
7. 2269 / 2 = 1135, x 14.7 = 16,677 PSI pressure required to achieve the same density of Hydrogen in the same size tank. This would be 2269 / 1568 = 1.45 times as dense as LIQUID Hydrogen, and far beyond current production technology.
8. Low molecular weight hydrocarbons are the most efficient way to store Hydrogen that God ever designed, and if you want something better, you should ask Him to do it. According to His rules, the fuel of the future will not be much different from what we use today, whether we continue to find and refine it, or manufacture it from other sources of Carbon and Hydrogen.
NOTE: I realize that I used a mixture of units, but I wanted to use familiar terms and measures where possible for clarity, while using constants and characteristics that would be easy to verify.
Car and aircraft manufacturers obsess about weight, and adding hundreds to thousands of pounds to each vehicle is futile. It might work for trains, boats, trucks, and buses.
I agree that there would be a longer ways to go for Hydrogen to become a feasible vehicle/transportation fuel.
I see a lot of hybrids on the road today, and my hunch is that the electrical production for such vehicles will become much simpler if we get something like this hydrolysis technique to work on an enterprise scale.
I wonder if a suitable carbon source might be coal, since it’s so abundant in the U.S.
Also, similar techniques are used to break up ocean water into its components as a purification process (similar to reverse osmosis). So this kind of technology holds promise on two of the most pressing issues — energy and water.