Pre-Budget Report

[Penners]

Hydrogen, of course, is not a fuel, just an energy carrier, so cannot be a substitute for fossil fuel.

That's an interesting statement. Aren't all fuels energy carriers?

Any substitute for fossil fuels would need to be (a) combustible, (b) transportable and (c) storeable. Doesn't hydrogen satisfy all of these criteria?

OK - I'm ignoring such matters as availability and affordability, but I'd be interested to hear why you made the statement above.

 

[biffvernon]

No, there's a big and very important difference. There is no free hydrogen lying about. You have to put energy into water to split the oxygen and hydrogen. Then you can carry the hydrogen about in your car and burn it to get the energy out again. But you had to have some other energy, oil, wind-power or whatever, to start with.

It's perhaps more useful to think of hydrogen like electricity - you have to generate it first but then it can do something useful somewhere else. Once you've 'generated' some hydrogen it can be used for useful tasks like powering vehicles.

But don't go thinking that the 'hydrogen economy' is anything to do with solving the problems associated with Peak Oil.

 

[Penners]

OK, but in principle what's the difference between generating hydrogen electrolytically and drilling, extracting and "cracking" oil?

I certainly don't hold out any hopes that hydrogen will be our energy saviour, but these academic points are just interesting.

Might as well perish with an active brain.

 

[Flyfisher]

Hydrogen, of course, is not a fuel, just an energy carrier, so cannot be a substitute for fossil fuel.

Yes, I read that statement too but I wasn't entirely convinced.

Oil is only a form of stored solar energy, so what's the practical difference in using the sun to split water (once we figure out how, of course) into H and O2 and burning the hydrogen instead of oil?

Fuel or energy carrier, it's just semantics isn't it? Fossil 'fuels' are just one way of 'carrying' energy from the sun to our planet. PV is another (so is wind and wave if you think about it) and photo-splitting of water to release hydrogen is another. I wouldn't dismiss hydrogen so soon. And, of course, it's entirely renewable

 

[biffvernon]

OK, but in principle what's the difference between generating hydrogen electrolytically and drilling, extracting and "cracking" oil?(

All the difference in the world. It's our old friend EROEI.

Wnen you produce hydrogen electrolytically, you put in slightly more energy thatn you get out (Nothing in the real world is quite 100%). So the energy return on energy invested is negative
When you drill for oil (and strike lucky) you get much more energy out than you invested. You're actually stealing the energy that the oil forming bugs invested when they harvested sunshine millions of years ago.

 

[biffvernon]

...using the sun to split water (once we figure out how, of course) into H and O2 and burning the hydrogen instead of oil?

Now you're talking. Trouble is we haven't quite figured how to do arteficial photosynthesis yet. Plants are still much better at it than we are.

 

[Flyfisher]

Wnen you produce hydrogen electrolytically, you put in slightly more energy that you get out (Nothing in the real world is quite 100%). So the energy return on energy invested is negative

True, but irrelevant The energy input is coming from the sun, which for all practical purposes is an unlimited source. The issue is how we can capture energy from the sun.

So what if you need, say, 100 units of sun energy to collect, say, 10 units of hydrogen energy? The result is 10 units that you didn't have before from an effectively free and unlimited source. Surely this is a good thing?

It's much the same with PV systems isn't it? More sun energy goes into them than you get out in electrical energy - i.e. they are nowhere near 100% efficient - but that doesn't make them useless in energy collection terms. Or does it? :wink:

 

[Flyfisher]

...using the sun to split water (once we figure out how, of course) into H and O2 and burning the hydrogen instead of oil?

Now you're talking. Trouble is we haven't quite figured how to do artificial photosynthesis yet. Plants are still much better at it than we are.

Quite right, but imagine if we were as good at it as plants are - or maybe even better?! So wouldn't it be a good idea to be pouring massive amounts of effort into solving this problem? Wouldn't it be better to spend £24bn on this than some new nuclear deterrent? This is the sort of stuff our governments should be pushing for, not messing about with £5 air passenger taxes.

 

[biffvernon]

The energy input is coming from the sun, which for all practical purposes is an unlimited source.

Oh, a hydrogen economy based on renewable energy to produce the hydrogen is fine. But it's not the hydrogen that is replacing the fossil fuels, it's the solar/wind/wave/tidal/geothermal etc. The advantage of hydrogen is that you can put it in a tank on a vehicle (though the energy density is lower than petrol so you need a bigger tank).

Renewables research or nuclear weapons? = no brainer. Pity brains are in such short supply.

 

[Penners]

Well, today hasn't been a waste! I've learned something.

Thanks, Biff.

Flyfisher

Turning water into oxygen and hydrogen gas is a simple and well-understood process (or in my case, vaguely remembered from Piggy Hunter's chemistry classes). If I recall correctly, you need a glass U-tube, and two electrodes of platinum (plus, of course, some water and some electricity).

But I confess I can't remember which gas comes off at which polarity - I was probably too busy stuffing damp blotting paper down the nozzle of Nigel Murray's bunsen burner.

 

[Nemesis]

It's sad isn't it that since the demise of real ink schoolchildren have been denied all those wonderful heartwarming memories of their schooldays which only ink and blotting paper could provide?

 

[Flyfisher]

But I confess I can't remember which gas comes off at which polarity.

If I can remember my A-level chemistry correctly, I think hydrogen ions (H+) will be attracted to the cathode (-ve) and oxygen ions (O-) will be attracted to the anode (+ve).

Slightly scary story: I remember trying to produce hydrogen in my bedroom at home when I was about 12 years old using an old fishtank (no fish!). I didn't understand at the time why it didn't work since I thought that a nice high voltage like the mains should produce loads of the gas :shock: Of course, it didn't work at all because it was AC :roll:

I remember knowing it was a dangerous thing to try so I was very careful to avoid getting a shock. At least I was successful in that respect. It was a good thing I didn't know where to get mains-rated diodes at the time or I might have been more successful and blown the house up with a hydrogen explosion!

Happy days

 

[Penners]

True - although I can't say I mourn the demise of the dip-pen and inkwell.

I always seemed to end up being ink monitor (which was one of the lower echelons of punishment at my primary school). This involved filling up all the inkwells in the class from a massive jar of ink, and God help you if you spilled any.

Mind you, on the plus side, dip-pens made good missiles, and a good launch could get one buried quite effectively into the classroom notice board.

I sound as though I'm 150 years old, don't I?

 

[Jane Smith]

I thought you were, Penners. At least.

(I hope you're the same Penners I used to know over at the old Period Property website... if not, I could be in trouble. And anyway, where's old Grimsdale gone, and the stunning Brunhilde? Were they banned?)

 

[Nemesis]

Grimmers and Brunny decided the new look sanitised forum wasn't for them, and departed sadly.

(I still liked the format so much better than this...)

Ev

 

[Gervase]

Grief woman, there can't possibly be two of them with the same sense of humour - it has to be the same penners.
I think Grimmers and Brunhilde were forcibly retired by the sanatorium staff for, er not projecting the proper sense of decorum when it came to old crocks. Conduct unbecoming, or something like that.
Oh, and Grimmers was caught p!ssing in the limewash.
.

 

[biffvernon]

Purely coincidentally, Bryan Rowbotham disappeared at the same time.

 

[Nemesis]

Bryan has been very busy:

http://www.lapvent.co.uk/millennium_products_award.html

 

[Penners]

Grief woman, there can't possibly be two of them with the same sense of humour - it has to be the same penners.

Yup - same old Penners, same tired old attempts at humour.

Sorry

 

[Jane Smith]

Grimmers was caught p!ssing in the limewash.
.

He told me that you had to do that to make it properly. The tea he made always tasted strange, too.