h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I remeber learning about electrolysis and I also remeber doing an experiment with two nails and some salt water which I am sure you have done before. I have seen advertised recently a hydrogen powered car. All this got me thinking. Surely it cant be hard to have a power station that uses electrolysis and then burns the hydrogen like they would do with coal.

true, but the efficiency of electrolysis is less than 100% so something has to generate the electricity to perform the electrolysis to generate electricity so you might as well miss out the electrolysis step and use the other energy source

That is true but there are other energy sources which could start of the circle. You obviously need electricity to separate the hydrogen from the oxygen then travel it into an empty tank. Then make a spark to set fire to the gas which would flame up to heat a tank of water above like with coal. The end product of burning hydrogen is water so you the reuse that water for either for separation or boiling. The water that is boiling in the tank would create steam. The steam would spin the turbine to generate electricity. The steam would condense and then can be reused.

There have been plenty of experiments with hydrogen-powered cars. As a method of storing power, hydrogen seems to be quite good.

There have also been experiments with cars driven from compressed air, and from flywheels running at very high speeds. And of course batteries.

All of these, including the hydrogen, are just ways of storing the power. You have to make the power some other way.

good point Gnomon - one that is often missed. There's various fuel cell powered gadgets coming about as well.

I don;t have a problem with the electrolysis to generate hydrogen and store the energy - I just don;t see the point or practical use of generating electricity by converting the electrical energy into a hydrogen storage and then converting that back to electricity. Each step incurs a loss so why not just stick with the original electric source? More power, less side products etc. But the main problem is the <100% efficiency meaning at some point you have to introduce energy into the system. Since that energy isn't doing anything except generating energy (of the same kind no less as that it is using) why not miss out the middle steps and just use that?

Maybe I ain't getting something though

Hydrogen is an excellent way of storing energy. Unfortunately, there are still quite a few practical difficulties with storing hydrogen itself. I must go and dig out my degree thesis - I knew it'd be useful one day.

JHawkesby - you don't quite seem to have grasped the fact that you can't actually carry out a process with 100% efficiency. Electrolysing water and then burning the hydrogen produced will actually result in an energy deficit, due to friction lost in wires, incomplete combustion and a multitude of other things. And that's even before you consider the lumpen and inefficient idea of a turbine.

B

I still recall (and my niece recently expressed similar disaapointment) my complete disappointment when I learned how a nuclear reactor actually generates electricity. Using steam turbines seems somewhat of a letdown really.

The big deal really with hydrogen as a power source, is that its quite easily transportible, in the same way that batterys really arn't very transportible (theyre crap and weigh a lot).
The issue does come down to where the initial energy, required to perform the electrolsis comes from.
the most well-thoughtout thing I remember reading/hearing on this issue was quite a few years ago now. They were looking at some of the big hydroelectric damns in err Europe somewhere I think. One of the big problems with HEP is that you can't just turn it off, it basically produces electricity pretty-constantly day and night, and at times of the day when the energy isn't relaly required there was problem of waht to do with the energy. BAtterys really arn't good neough for storing vast amounts of energy in that way.
The idea was (don't know if theyy went on to actually do it or not). Use this excess electricity to electrolyse and produce Hydrogen that could be easily stored and used as and when required. Of course the other advantage being there was alreayd a really nice big source of water to hand...
The other advatage that has been put forward for using hydrogen powered cars, in particular, is an issue of reducing local polution, in big busy citys it'd just do away with car polution at the actual road level itself Of course that'd need a pretty high takeup, which I guess isn't easy as people won't just tend for the hell of it to get rid of their perfectly good working car to just buy another albeit a hydrogen powered one ,run>

I do understand about the 100% efficiency. All I was doing was raising a point that is going around at the moment. I just wanted to explore alternate power sources. Does anybody have any other suggestions. I like the idea of running a car on compressed air.

My suspicion is that as data transfer rates and human apathy continue to increase, there will rapidly become little need to run a car at all.

B

Hello again jh I'm glad you asked this, as it certainly is becoming a popular idea. The thread i started about 3 weeks ago... http://www.bbc.co.uk/dna/h2g2/classic/F19585?thread=5863302 ...died apparently, although i have been meaning to update it with new results. Everyone trots out the old line of "Yes but it takes more electrical power input than you get HHO power output". I don't believe this is necessarily true just because a lot of people half remember their physics teachers saying something like that in class. Water IS already H and O . That means it has potential energy already...doesn't it? By splitting it using electrolysis you make that already existing energy available to burn. Why does it necessarily follow that you have to put more energy into the water than you are taking out? If something already has Potential energy, eg: a ball at the top of a hill, held in place with a string. How little energy does it take to simply cut the string compared to the huge amount of energy released when the ball starts rolling ? 1 litre of water can be converted into 1,800 litres of combustible gas using electrolysis. I have installed one of these devices on my gas guzzling white van. It mixes the gas produced in the jar directly with the intake air in the inlet manifold. My mileage has increased from 11mpg to 16mpg. 3 weeks ago, i installed one on a friends Jeep Cherokee. Her mileage went from 13mpg to 20mpg. I don't know yet if it would be possible to run solely on the gas produced by electrolysis powered by electricity made by the mechanical output of the same engine, but that would be the ideal. I'm currently experimenting with a small 5kW generator to see if it can be done. Because H is highly explosive, you have to be very VERY careful about storing it under pressure or transferring it. Installing a hydrogen tank in a moving vehicle, that is quite likely to be hit by some other moving vehicle seems to be asking for trouble. OK...How about this guy ? Look, he seems to be generating 900W of power using NO FUEL !!! http://www.youtube.com/watch?v=8fR3vBB1Yn0 He says it's just a conduit for all the power that's "out there", it's not a generator... alec.

It is very interesting to see that. I was thinking a bit earlier that although you need to take out a bit of energy you just have created from electrolysis there must be extra energy. The great thing about electrolysis is that it is reuseable. Does anybody think there is another good alternate power source.

"Everyone trots out the old line of "Yes but it takes more electrical power input than you get HHO power output". I don't believe this is necessarily true "

Maybe not, but unfortunately it is. For one thing, try electreolosis. Are hydrogen and oxygen the only products? No. 1) heat is generated and 2) there is a build up on one of the electrodes (can't remember which). Shove two long screws connected to a large battery into water and one of them will corrode. That's because some of the energy is oxidising (or somethingising) the electrode.

Equally, when you burn the hydrogen to produce heat to turn water into steam, some of that heat goes into the container of the hydrogen. Some goes into the container for the water. some goes into combinig the hydrogen with oxygen. Again, why waste this energy?

"The great thing about electrolysis is that it is reuseable"
yes, but on a downward spiral. The water generated is less than the water used.

Heck, if you believe otherwise, patent it. You'll make a huge fortune out of the worlds first perpetual motion machine.

Hear hear.

This thread is the very epitome of what happens when uninformed people get their hands on scientific ideas. If we could create energy out of nothing then Canot would be turning in his grave, as the Universe imploded upon him.

B

Then PLEASE explain why i am saving gasoline, instead of having to put more in.

thanks

alec.

I can possibly be convinced that it will work for short periods and save a fraction of fuel costs. I wouldn't, however, care to vouch for the state of your van's spark plugs and head gasket. Good luck on your next service.

Surely, though, you must realise that any such economy approaching 100% is ridiculous?

B

I didnt know that you get less water back but where does the rest of it go.

Dissipation as heat energy.

B

indeed, please see post 13.

Just had it serviced thanks Mu. 2500 miles now with the gas generator attached. "Plugs look clean" he said.

Why will you not answer my question?....aah, i see why, it's because :

" This thread is the very epitome of what happens when uninformed people get their hands on scientific ideas."

So what you're saying is that we've no business tinkering with stuff that's er beyond our limited grasp ?
Is that it ? *tugs forelock politely*

" If we could create energy out of nothing then Canot would be turning in his grave, as the Universe imploded upon him."

Who said 'nothing'? i'm using water. H and O...what's not to burn?
The device takes a mere 7A from the alternator.


"Surely, though, you must realise that any such economy approaching 100% is ridiculous?"

Yeah, you're right...i guess i'd feel pretty stoopid driving down the street if i only manage to cut my fuel bill in half.

...and dont call me Shirley !!


alec.