I have a question about the whole hydrogen hype. I know that you can electrolyze water into Hydrogen (and oxygen). My question is how do they "bottle" the gas? They always seem to leave that part out when explaining it.

I was thinking last night that hydrogen power could be a scary thing economically. The electric company could also be the gas company (selling hydrogen as an alternative to propane or city gas), and possibly water (the by-product). Any thoughts on this? Impossible? Unreasonable? Prepare to play monopoly?

It takes more energy to get the hydrogen out by electrolysis than you get when you burn it back to water. If the energy was "free" (solar or something) you might be able to make a case, but why not just use the electricity to charge a battery?
Most commercial hydrogen comes from natural gas although it is a byproduct of some chemical operations. It is captured, purified and compressed.
You also have the storage and distribution problems but that is just a market issue.
Until we solve the supply problem, hydrogen is a fantasy.

As far as how to capture the gases, it's just a matter of proper design of the equipment. Here is a typical laboratory device used for demonstrations:


The gas bubbles rise from the electrodes, and collect in the vertical glass tubes, where the gases can be drawn off via stopcocks. The basic design could easily be scaled up to whatever size you want.

[This message has been edited by NJwirenut (edited 08-12-2006).]

[This message has been edited by NJwirenut (edited 08-12-2006).]

We ran a number of hydrogen fuel cell busses on a single route a few years ago. The fueling point was located well away from the rest of the maintenance facility. (unlike the diesel fueling) I feel more comfortable around nuclear fuel sources than hydrogen. Maybe I'm just amplifying those little pop sounds we all heard when they put the burning splint in the H tube, in my head, scaled up to fit a bus.
Joe

Hydrogen is not particularly dangerous and certainly not as bad as gasoline fumes or natural gas. It's pretty hard to make it hang around long enough to accumulate since it is so much lighter than air. A small vent in the roof would let it go away immediatly.

Once we get over our nuclear phobia it could become a viable fuel but you need energy to spare to make any quantity of hydrogen at a reasonable price. In a nuke plant they might even come up with a thermal cell, sort of a fuel cell running backward that outputs hydrogen.
Then we would be down to designing the transportation and distribution chain. The other big problem with hydrogen is the molecule size. A submicroscopic pore that would hold back a methane molecule is an open door to hydrogen. That is why your helium balloon seldom lasts the night (pores in a latex balloon) and helium is twice the size of hydrogen.

I never really understood all the hydrogen hype. To me, the fuel cell and the fuel tank seem to be just another type of battery. I'm thinking why not just use a bunch of batteries?

Turning it into hydrogen sounds good to me if you're gonna burn it (e.g. water heater, etc.), as there would be no worry or CO poisoning and no CO2 for global warming (even though HOH is also a greenhouse gas). As far as storage for electricity, I don't see any advantage for hydrogen over a storage battery, other than maybe maintenance.
Batteries leak a charge, but the large liquid gas tanks probably leak slightly too.

Then again, I did fail high school chemistry (but I did excellent in Physics I & II), and I haven't taken it in college yet.

NJ & gfret - so, if they make H by electrolysis, do they use the setup NJ shows and hook it to some type of compressor?

the chemistry ignorant,
-Josh

I hate to be pessimistic, but all these ideas like 'H' powered cars, wind farms, solar power, bio-fuels, tidal barrages, nuclear power and the like are dead ends.
If we don't stop our profligate use of energy, our civilisation, like all those before it, is finished. Period.

I give it another 100 years, maximum.


Alan

Yes they do need to compress the gas and in most schemes it ends up having to be cooled to a liquid to get the energy density needed for long range travel.
I agree hydrogen is just a battery but it is in effect instantly rechargable.
BTW the thing nobody talks about are the oxides of nitrogen you get when you burn hydrogen in air. That is still simply a function of heat and nitrogen which is about 80% of air. You will still need pollution controls on your car.

I think the answer is cogeneration. No gases should be burned for any process or heating without turning a turbine to generate electricity. All gas appliances (except maybe cooking) should have a mini turbine within them or the mechanical systems of homes altogether nead to be more integrated and/or thought through.

Could you imagine how much electrical energy could be created using even 10% of the natural gas we burn just in residential water heaters?

Then the grid becomes your battery. excess energy gets deposited to be withdrawn when needed.

I always forget that our air is 80% Nitrogen. Every time someone reminds me of that, I start to feel like I'm suffocating. You're right, I forgot about the compunds of nitrogen. Assuming you burned 1 kG of gas (or petrol if you prefer) and 1 kG of hydrogen, would you have less, more, or the same amount on Nitrogen compounds from one or the other?

gfretwell,
I was just thinking about the instantly rechargeable part of your post. Anything not attached to the earth, if powered by battery would take hours to charge and would have to sit idle, or take a few MINUTES pumping Hydrogen into a tank.

I'm still undecided on the whole hydrogen thing as far as the grid goes. I don't want to go into nuclear because it would be too political, but if you want to discuss it privately, feel free to drop me an email.

As for being pessimistic about any type of energy, in reality, on a long enough timeline, everything drops to zero. An example:

It's dark, no power. You're trying to get your generator running. You have one candle (the kid next door borrowed your flash light last week and wore down the batteries.) You have two options:
1) Light the candle at one end. You will have a small amount of light for one hour
2) Light the candle at both ends. You can see better, but the candle will now only last a half hour. However, you can work faster because you can see.

Conclusion: With non-renewable resources, no matter how much you use or conserve, the same amount of energy will be used and the same amount of work will get done, the only thing that fluctuates is time.

As for renewable resources, they are here indefinitely. The devices we use to generate power are very reliable... but the energy they capture isn't. (for instance, a wind generator making zero volts on a windless day can be said to be reliable, as it is performing to specs. If it's not turning but is somehow making power, you probably just ripped a hole in the fabric of space-time.)

I can see hydrogen's uses in automobiles, but as far as grid power, i can only think of things such as long term storage, such as excess solar energy stored for winter when there's less sun. However, this seems very expensive and more like a last ditch effort rather than high-tech innovation. Don't get me wrong, it will technically work, but it seems more like hopeful hype. After all, there arent any batteries on the grid right now, unless you consider unspent fuel to be a battery, which it technically is)

I have seen hydrogen back up generators, and they look pretty cool. Plus from what I understand, the water coming out can be used for heating when it's cold. It might be a good option for remote places too, but it doesn't seem very feasible for grid use.

I hope this isn't too political, but why not use felons to generate some power? Every able-bodied prisoner takes shifts on some exercycles connected to generators. Parking ticket? $50 fine or an hour on an exercycle. Rob a bank? Mandatory 20 years of 8 hours a day on one. Of course, you still need fuel (food) and there will still be waste (unmentionable but you get the picture)

I think the problem with the bike generator is about the same as the gas turbine on your natural gas line. Too much machinery for miniscule amounts of power. It might make some sense simply as a symbolic punishment for Enron executives but I think you would save more energy letting inmates cut grass with push mowers.
In the case of the gas turbine you are only moving the pumping energy from the gas plant to the customer's turbine. "There ain't no free lunch".

I understand your point gfretwell. I'm only suggesting getting 60-70% efficiency in energy conversion by making the burning process "work" before we take the heat from it verses the (20%? + or -) from the straight burn. It cracks me up to see a high efficiency furnace claiming 92%. I also understand no free lunch. I'm only suggesting brown-bagging some left-overs.

And I should restate the begining of my previous post from "the answer" to "one possible contribution".

[This message has been edited by Jps1006 (edited 08-14-2006).]

JPS, I think you're out of luck on your cogeneration plan. Those "92% efficient" furnaces and boilers really are in that range. They actually condense the water vapor out of the combustion gases, and the final result is exhaust that's cool enough to be vented out in PVC piping. There is pretty much no energy left to extract at that point.

We had a thread recently about a NZ-built ac generator which used the waste heat from the engine for space heating. It had a natural or propane gas fuelled Stirling hot-air engine, I think, and fed excess power to the Grid. I believe it fitted into the airing cupboard.

Now, provided the engine has a nice 'clean' burn, so as not to waste gas, and the exhaust gasses heat can be captured efficiently and not lost up the flue, the actual thermodynamics of the engine are irrelevant [within limits]. The overall efficiency has to be better than most power-stations since there, the waste heat is mostly lost to the atmosphere in the cooling towers. It all depends though on the price the poco pay you for your excess juice.


So, there may just be free lunch after all!

Alan

Now this coming from high school and some college education:

I don't doubt 92% efficiency at extracting heat, (and yes I know that's what they are talking about) but how about extracting energy. It's the expansion of the heated gas (that could be driving a motor) - I believe it is referred to as kinetic energy as opposed to thermal (convection or conduction). There's more than just heat in that there fuel.

I don't have the education or the background to really throw out stats & specs, but my gut tells me there could be something to it.

jps, your gut feeling is absolutely right. 92% efficiency is true too, no BS, [for 'condensing' boilers].
What the ads don't tell you is that the guts rot out of them in 3 or 4 years because what 'condenses' is.....acid.

For the Munchkin boilers perhaps. The Vitodens boilers, which use a stainless steel heat exchanger, are generally considered to be a 50-year boiler.

Jps, by the time they've extracted that much heat from the combustion gases, there is very little expansion left. The energy just ain't there--it's been used to heat the water.

[This message has been edited by SolarPowered (edited 08-14-2006).]