Hydrogen-Powered Cars – A Pipedream
Written by Dr. Klaus LE. Kaiser
A recent edition of our newspaper had a 24-page insert with the title “Green Agenda.” Actually, it’s a so-called Special Information Feature, AKA an “infomercial” on new car models and technologies.
That insert could lead you to believe that the touted “green technologies” will save both the planet and your wallet, neither of which is true though.
The Hydrogen Pipedream
Especially amusing or annoying (mostly the latter) are claims about elemental hydrogen as energy carrier of the future. It’s the same nonsense which you could see in TV commercials and read in the newspapers fifteen years ago. At that time we were told that hydrogen-powered cars were to be in car dealers’ showrooms by 2001, “ready to drive away.” Now, a dozen years later, the hype is still the same and nothing has changed, except for the “green alliances” for “sustainable future technologies” between some car manufacturers and the new date when it is all supposed to come together, now predicted for 2017. Of course, big government-sponsored handouts are available for such developments.
Elemental Hydrogen Properties
The properties of elemental hydrogen are extreme. In liquid form it can only exist at temperatures below MINUS 250 C (MINUS 415 F), which is not far above the absolute ZERO temperature (MINUS 273 C). Except for helium, no other material exists in either liquid or gaseous form at the temperature; even oxygen and nitrogen are rock hard solids then.
Therefore, any idea of using liquid hydrogen as common energy carrier in automobiles is out of the question. It would rapidly evaporate even with the best thermal insulating materials around any tank and lines.
Above its triple point, which is MINUS 250 C for hydrogen, any material can only exist as gas. That means that in order to use elemental hydrogen as a common energy carrier it would have to be strongly compressed and transported in thick-walled steel cylinders. Even at an extremely high pressure of 20,000 psi (or 700 Bar, comparable to deep parts of the ocean), the volume of a typical automobile gasoline tank would only contain a few pounds of hydrogen.
Therefore, compressed hydrogen gas is no viable option either. To begin with, the energy requirement for compression is quite large. Then, because of the small size of the hydrogen molecule, it is able to migrate through many solid materials, even steel. Under pressure, it also reacts with the small amount of carbon in common steel which makes that brittle and unsafe. But that is not all that argues against the use of hydrogen as energy carrier.
Probably the most serious argument against the common use of hydrogen is the fact that it has the largest known flammability range of any gas in mixture with air. Between five and 95% hydrogen in any mixture with air will explode with the slightest spark or on contact with a hot surface.
Can anyone seriously expect that of the millions of cars on the road (potentially with either liquid or compressed hydrogen as fuel) none would ever develop any fuel leak that would lead to powerful explosions?
We actually use a lot of hydrogen for fuel, however, not in elemental form but as chemical compounds with carbon, summarily called hydrocarbons. These hydrocarbons are termed gasoline and diesel fuel. They are liquids at common temperatures and quite easy to handle. You can pour them from one container into another without problems and they have been around for a more than a century. Very simply, hydrocarbons are the energy carrier of choice.
Gasoline or diesel fuel is not only quite safe and easy to handle, it also carries a lot of punch. For example, any volume of it contains more bound hydrogen than you could possibly have in the same volume of liquid or compressed elemental hydrogen. In gasoline or diesel, the bound hydrogen has a slightly lower energy availability than in elemental form, but that small disadvantage is negligible compared to all the disadvantages of hydrogen in the elemental (pure) form.
As long as bureaucrats and politicians are willing to spend your tax dollars on the (elemental) hydrogen-as-fuel idea, you can’t blame the car manufacturers for making all kinds of promises.
The fact is and will remain: Elemental hydrogen as energy carrier for cars is a pipedream.