Bunker Mulligan "Let us endeavor so to live that when we come to die even the undertaker will be sorry." ~Mark Twain

March 22, 2005

Hydrogen Cars

Filed under: Engineering — Bunker @ 6:55 pm

Dick Morris may understand politics, but he knows nothing about physics.

In what is otherwise a good article on the things Arnold is doing as Governor of California, Morris errs…

Replacing gasoline engines with hydrogen-fuel cells would eliminate two-thirds of America’s need for oil — a demand that we could meet entirely with domestically produced oil.

Well, not exactly.

A typical automobile engine is about 25-35% efficient, which means 25-35% of the energy from fuel is converted to work. That takes into account all the power the engine must generate to push the car through the air, provide power for electricity generation, and drive such things as the air conditioner compressor. The drive train itself is only about 85% efficient. Things that will always be involved in the equation, regardless of power source.

What about these hydrogen cars? Will they reduce automotive emissions? Yes. So Morris is partially correct in that his numbers refer to the amount of energy saved in automobiles. But that hydrogen must come from somewhere. And that will require burning of oil (or coal) somewhere other than in the car’s engine.

Yes, that energy conversion process will probably be far more efficient. Maybe at 65%. But the electricity must then be transported, with attendant losses–perhaps 90% efficient. That electricity is then used to separate hydrogen and oxygen. That is only about 80% efficient. Then the hydrogen must be stored at cold temperatures and/or high pressures, and that costs more energy. And losses. Let’s be generous and say it is 95% efficient.

Then, the recombination of hydrogen and oxygen in a combustion is about 75-80%.

What do all those numbers mean? Well, if we multiply all those efficiencies we get a net efficiency of 33%, and that is being generous.

Running an automobile on hydrogen is about the same as running it on gasoline, and requires just as much fuel (oil) and generates just as many fumes, although the car itself doesn’t.

One other thing people don’t realize is that the hydrogen burning with oxygen also burns with other elements in the atmosphere. After all, air is mostly nitrogen, with some oxygen and a few other gasses–not to mention particulates in the air. Hydrogen is also a prime ingredient for all acids, such as sulphuric and nitric. As in sulfur and nitrogen being combined with hydrogen in water solution.

These are all very rough numbers found in five minutes of searching the internet. I don’t write all this to say we shouldn’t be looking at alternatives. Perhaps those efficiencies can be improved. Perhaps the extraction of hydrogen can be done in other, more efficient ways. And perhaps the storage problems (remember the Hindenburg?) can be resolved. I write all this simply because too many people will take up the cause without understanding the complexities involved.

Dick Morris is but one. And as things now stand, the reduction in oil requirements would be… well, zero.


Hud is thinking along similar lines as he talks about the ozone “hole”.


  1. Well, Bunker, I’m a hydrogen skeptic; and you’ve done a good job of quantifying my reasons.

    But in a rational world, there WOULD be a way to run cars on hydrogen AND reduce emissions. Nuclear plants would do the job nicely.

    Comment by UML Guy — March 22, 2005 @ 9:37 pm

  2. If only the loonies would listen.

    Comment by Bunker — March 23, 2005 @ 5:22 am

  3. excellent post Bunker!

    Generating all that Hydrogen is indeed the problem. However, it’s a much easier problem to solve than our current problem of complete reliance on a dirty, limited fossil fuel.

    Nuclear Power is the easiest solution. I personally don’t see why we can’t pursue that option. Disposal of the nuclear waste is a problem, but one that has some solutions on the horizon.

    Solar and Wind energy are other possibilities, but they need giant leaps in efficiency and basic technology to get moving.

    The more I think about it, the more I think that Fusion is humanities only hope for sustainable energy generation. But that is probably 100 years away from being economically viable.

    Comment by Chris — March 23, 2005 @ 9:32 am

  4. […] rky View Striving for perspective. March 23, 2005 Bunker on Hydrogen Bunker Mulligan has an excellent post today about the realities of switching to a Hydrogen […]

    Pingback by Murky View » Blog Archive » Bunker on Hydrogen — March 23, 2005 @ 11:34 am

  5. If only the loonies would listen.

    They’re listening already, actually. It’s a painful transition, to be sure, but it’s happening.

    Now stop wasting time calling them loonies and go convince the rest of them with the brilliance and powers of persuasion of which we know you’re capable. ;^)

    Comment by Bogey — March 23, 2005 @ 12:39 pm

  6. Sorry, Bogey, but it’s going to take more than one article in a tech-friendly magazine like Wired before I’m convinced that they’re listening. For at least the three decades I’ve been paying attention, they’ve done nothing but spew irrational pseudo-science on this topic. They’ve trained most of the non-scientific public to be not just uninformed, but MISinformed on the topic. It’s going to take more than Bunker’s brilliance to change that.

    Comment by UML Guy — March 23, 2005 @ 12:54 pm

  7. Well, UML, there’s a lot more out there than the two Wired articles I linked — those just happened to be the ones I remembered reading and found quickly. It really looks to me like this has been a common topic in environmental blogs and magazines for a while now — Google green nuclear power, sift through a few pages of results for a taste; try similar searches on Technorati and Feedster too, if you have time.

    So let me back off on the strength of my first comment: I’m not asking you to be convinced that they’re listing… I’m trying to convince you that some of them are starting to listen, and that there is real opportunity in that, because:

    …in a rational world, there WOULD be a way to run cars on hydrogen AND reduce emissions. Nuclear plants would do the job nicely.

    I couldn’t say it any better than you did the first time. 🙂

    Comment by Rob L. — March 23, 2005 @ 1:23 pm

  8. Thanks! I’ll take a look. I seldom say this, but I’d love to be wrong.

    Comment by UML Guy — March 23, 2005 @ 1:26 pm

  9. I would, too. But every time anyone mentions nuclear power, a small group of very loud people make politicians squirm. And the regulatory agencies are full of such people. I can tell you from painful experience that they are the ones holding things back.

    And that is the real issue. The Nuclear Regulatory Commission, like every other federal agency of its type, is staffed by people who see it as their mission in life to insist on perfection in whatever they regulate. Even though they cannot be fired, they fear for their jobs and their personal prestige.

    Comment by Bunker — March 23, 2005 @ 2:08 pm

  10. Very interesting thought, Bunker — I think that is worthy of a post all its own. “Problem Pefectionism” has a nice ring…

    Comment by Bogey — March 23, 2005 @ 2:26 pm

  11. Voltaire: “The perfect is the enemy of the good.” (Sometimes translated as “The best…”)

    Any article that discusses the cost of power — heck, of ANYTHING — should include the cost with and without regulation. When it comes to nuclear power, the regulation cost is a significant chunk of the whole.

    Also, regulators never get judged on what didn’t happen because they said No; but they can get burned at the stake for what does happen if they say Yes. So that’s one more predisposition to say No.

    Comment by UML Guy — March 23, 2005 @ 2:43 pm

  12. After reading Chris’ post (trackback above), another thought entered my mind. Hydrogen-powered cars would generate steam. Can you imagine what rush-hour would look like? How about downtown stop and go traffic?

    Comment by Bunker — March 23, 2005 @ 6:11 pm

  13. Why hasn’t someone invented a car that runs on phlegm? I’d be a rich man. Larry the Phlegm Baron, they’d call me. Cars would line up in front of my house. People would come from miles around for a jar of my high-performance lung butter.

    And think of all the money we’d save on health care. There’d be no need for a flu vaccine, because everyone would WANT the flu. Hospitals would be able to turn a sizeable profit simply selling barrels of phlegm to refueling stations, which would in turn enable them to lower medical expenses.

    A pipe dream? Probably. If anyone invented a car that ran on phlehm, Bush’s big oil buddies would give him a Columbian necktie for his troubles. Perhaps that’s exactly why we don’t see any Chevy Phlegmwagons on the freeway.

    or perhaps it’s just the NyQuil talking.

    Comment by Liberal Larry — March 23, 2005 @ 7:19 pm

  14. Larry,

    More NyQuil, more sleep. If you’ve got the sort of crud that’s been going around here, then I highly recommend crawling into a warm bed until it passes.


    I’m a software guy, not a thermodynamicist; but it seems to me like they ought to be able to route the steam past some sort of cooler or condenser that would convert it to a cool mist or even a stream of liquid, which would then settle to the ground.

    Or maybe they could even route the steam through the heating/cooling system for heat transfer purposes.

    Comment by UML Guy — March 24, 2005 @ 1:24 am

  15. Personally, I think Larry’s on to something.

    The only way you could condense the steam would be with some kind of heat exchanger placed in the airflow, similar to the car’s radiator. The radiator, with some kind of control loop to manage flow, might serve the purpose itself. It would need to be far better than those on vehicles today. I doubt there would be much use for the energy in the steam except to possibly power a turbocharger on the engine. With hydrogen burn efficiecy at about 75%, that would certainly improve things by increasing airflow into the engine.

    At that point, we’d have wet roads in perpetuity, and waste runoff to handle. Let’s just say I’m not optimistic about the potential for hydrogen-powered vehicles.

    Comment by Bunker — March 24, 2005 @ 5:28 am

  16. I’m in favor of research to promote hydrogen as a fuel source. It’s
    not because of “global warming”, but for the simple fact that America
    needs every source of energy that can be utilized. This is a national
    security problem which worries me.

    Ford is working on an hydrogen powered internal combustion engine.
    They say that they can bring this car into production within two years.
    The exhaust is cleaner than the air that goes in. It cleans the air,
    so they say.

    There are vast stretches of America’s heartland which are suitable for
    windmills. Wind energy is currently cost competitive. How to use that
    energy for hydrogen production and transportation is another problem,
    but it may be feasible. I hope so.

    Comment by boots n oil — March 24, 2005 @ 5:37 am

  17. How about routing that steam through a pipe in the console to make a coffee cup heater. Might get you through some long drives better than that old green thermos of yours.

    Comment by Slice — March 24, 2005 @ 9:37 am

  18. Don’t be talking bad about my travel pod!

    Comment by Bunker — March 24, 2005 @ 10:24 am

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