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Space/Science » in reply to re: Producing hydrogen locally

re: Producing hydrogen locally
Yeti — (archived)

I have no strong opinion one way or another about the glory or problems with a Hydrogen economy- However your remarks here are getting really odd. For example:

"Now add to that the simple reality that any pressurized tank used for a hydrogen vehicle will likely survive intact even the worst accident. Do you really know strong a tank must be to hold 10,000 psi? And if it does break open the hydrogen burns up vertically, not horizontally like gasoline does."

If they Hydrogen is indeed stored in a gas at 10,000PSI, if you do have a tank rupture, then I assure you that the chemical explosiveness of the Hydrogen is the very least of the problems. Instead you have to worry about the low-tech equivalent of a Kentic Kill vehicle flying around the roadway. A breached healium storage tank (of the kind that novelty stores used to fill baloons) can penetrate a cinder block wall as easily as if it were paper, and I think those hold far less than 10,000psi.

Furthermore, just because a tank is designed to withstand "10,000 PSI" internal pressure it does not mean that that tank is partucularily resistant against puncture, shatter or breach from external force. Its a logical fallacy to assume that strength for a given metric or context will extend to strength in other contexts.

If we ever do drive around in Hydrogen cars- which I sure wouldn't mind, I doubt that the hydrogen will be stored as a free gas... its more likely to be sequestered in tanks filled with Hydrogen-absorbant materials, such as Carbon- or as an easily liquified hydrocarbon gas, from which it can be 'reformed'.

Until we have cheap, abundant energy and clean processes for producing hydrogen en-masse, it doesn't make much sense to talk about a hydrogen-burning transportation infrastructure (Pebble Bed reactors are a good idea for this). Local 'home' production driven by solar is a neat idea, but until we get cheap low-toxicity, durable solar cells that are in excess of 50% efficient, I don't think (IMHO) that its reasonable. However, if we do have such 'DIY' production, then why bother with Hydrogen? Why not simply run electric cars? It makes little sense to loose energy transforming to a fuel if you have such a powerful 'at home' electricity production sytem.

Hydrogen is very explosive, and requires enormous pressures to attain reasonable energy-density as a fuel. Its not 'hindenburgh fear mongering' to point that out. Hydrogen is a 'cool' idea, but everything that is needed for a Hydrogen infrastructure is exactly what is needed for an electric infrastructure, but with a whole energy-losing layer (Hydrogen Gas Reforming) thrown in.

Basically, every argument I hear about 'going hydrogen' starts with either distributed or localized production of significant mounts of electricity. Thus, the 'green-ness' of a Hydrogen economy is only as 'green' as the method used to produce the electricity to reform the Hydrogen. Worse, if the Hydrogen is reformed from Hydrocarbons, then the CO2 emissions from that process have to be taken into account.

So, why use hydrogen? If you start with all that electicity, why not just use that instead? Electric motors may lack the lovely noise, but their pound-for-pound power production already exceeds internal combustion gasoline engines, at least on the scale of car engines.

I'm fairly amused with the level of bluster with which you have entered this discussion board. I am very curious- for what reason do you claim to be an energy 'expert'? Your arguments don't stand to simple reason- which is something I would not expect from an expert. You might get a better reception if you dropped the bluster and stopped acting like anyone who thinks differently from you is an idiot. This is not the place where that additude goes over well- if anything it is the place where that additude triggers serious resistence.

DL

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