Solar Hydrogen production

[Cheezy]

I recently saw the back end of a local news report about a school that was generating it's own hydrogen from solar cells. This was then getting burnt to produce power, they also use p.v and wind. Now I knew this was on going research, but I didn't realise it was available. Has anyone heard anything (Martin obviously!).

1. I wonder how efficient it is
2. How do you get over the storage problem, as you'd need to compress it, which requires a lot of power.
3. If you didn't store it could you use it as it's produced to make electricity and store that, or better still a CHP

As a solution to our energy needs it would be a nice one, as it's derived from water and solar energy, its a transportable fuel, burns to produce water. Has a slight problem with explosability, but hey you can't have everything.

[Smooth Hound]

I am unsure about this now, i have read alot about this and at first i thought this is great and in a sense the principal of it is , but i have been on alot of sites on alt tech and so forth and most seem to see it as a ded end, which i dont really know myself, i wouldnt mind my own little hydrogen cell thingy, but aparrently its something to do with the amount of energy being needed to produce hydrogen being more than recieved back something like that , oh and storage and transporting it , i think

[Martin]

As far as I understand it, you've hit the nail on the head - as an educational project, it's of great value, but is at the present state of development very energy intensive to make and store
I like simpler forms of storage - http://en.wikipedia.org/wiki/Pumped-sto ... lectricity - when you've got the power, pump water uphill, then when you need some, generate some hydro-electic energy from the stored water!

[Cheezy]

I'm with Martin, for the home ,water power is the way * I want to go, but if you could produce hydrogen (and oxygen as a by product), you could run the house on CHP AND the car on the gas.


* Of course the small point of finding a house with a decent water course/lake at elevaated height, with in my affordablity and that doesn't flood is a problem


edit

Just been reading this loverly bit of chemistry
http://www.dangerouslaboratories.org/h2homesystem.pdf

p.s Happy birthday Martin!

[Smooth Hound]

Interesting , that is what we have up here further towards the highlands, i thought that it was less than 80% power regained, so thats some good news, however if potentially it could be our future source, or one of them, its worrying that they intend on storing nuclear waste under ground, in old mines and so forth, even if the do insist its low risk wate, because those underground places could well be the low level lakes that would be suited for it.

[The Riff-Raff Element]

I'm with Martin, for the home ,water power is the way * I want to go, but if you could produce hydrogen (and oxygen as a by product), you could run the house on CHP AND the car on the gas.


* Of course the small point of finding a house with a decent water course/lake at elevaated height, with in my affordablity and that doesn't flood is a problem


edit

Just been reading this loverly bit of chemistry
http://www.dangerouslaboratories.org/h2homesystem.pdf

p.s Happy birthday Martin!

Or perhaps even a compressed air economy? Rather than moving water, use wind or solar power to compress air, store it and use it to turn a generator or even move a car...someone may have already written this up, so I apologise if I am reapeating, but a French manufacturer is launching an air powered car this coming autumn. As the rules stand on tax rebates on low emmission vehicles here, the govt would actually pay the consummer about €1400 and give them the car for free, though they have signalled they may need to make some changes to the law on this one.

I blogged it, if anyone is even remotely interested:

http://vendeeblog.net/?p=106

[Martin]

a friend of mine, who keeps very up to date on such claims is firmly of the opinion that this is a bit of a con............the last published data was a maximum range of 7 miles -- this has recently disappeared to be replaced by lot of "investor attracting puff"

[Smooth Hound]

Ok, below is my interpretation of a hydro elec system, only this is a 12 v one, the idea is to do it with 2 tanks, i have no idea how much higher the top tank would need to be than the lower one, no idea if my size of piping is correct, in fact this is just a diagram, that i have whipped up , just to show what i think is the theory of how it works, maybe if any one is intersested we could discuss things like that, and discuss a suitable alternator, water wheel, size of pump etc, as i say this one is for a small 12 v battery system, . So feel free to critisise, add info needed , make suggestions of products that can be used, and such things as the best degree of angle for the 12 inch guttering water run. Maybe between all of us we could come up with a suitable prototype( on paper for now) of a small 12 v hydro system, suitable for a house holder with a garden .

[The Riff-Raff Element]

a friend of mine, who keeps very up to date on such claims is firmly of the opinion that this is a bit of a con............the last published data was a maximum range of 7 miles -- this has recently disappeared to be replaced by lot of "investor attracting puff"

Hmmm...perhaps it is, though on the website and in an interview published last month they are claiming 140-150km for running solely on compressed air. Maybe they were doing it downhill all the way.

Nègre does seem to be attracting quite a lot of investment and I imagine that some of these people would have done their due dilligence. So far no-one has cried foul as far as I can see. Plus the Ecology Ministry are taking an active interest in what he is doing (well, they would if they thought that they might end up paying people to take the cars away); I'd hope that they'd check his bona fides (then again...).

I guess we'll see for sure if / when he starts selling the cars. I'm enchanted by the idea, I'll admit. I'd take €1400 off the government for the privilage of driving around on thin (or, rather, thick) air.

[Martin]

on the small hydro idea, it's always good to have some real life figures to play with...............
So, just for illustration purposes, there are simple hydro units available- these are the figures from the smallest "high head" model (10 or more metres head) - 200 watts at 3 to 4 litres per second...........
So, as an example, if you wanted to produce 200 watts for an hour, you'd need something like 12,000 litres of water..........
Which if my metric maths is up to it, is 12 cubic metres of water (a pond a metre deep by 3 metres, by 4 metres), which has to fall 10-12 metres....
12,000 litres an hour............if that were to run for 24 hours, it would only produce roughly HALF the amount of electricity used by the average uk home in a day........which rather brings home how profligate we are with energy (you'd need a reservoir of around 2 metres deep x 9metresx 16metres just to give that half........)

[Smooth Hound]

so what do you reckon the size of the system would need to be for a trickle charge, one not necessarily for half a houses needs , but say for 2 people in a 20 ft caravan, so just for 12v lights and a couple of 12v appliances, heating is solid fuel., what for example could i produce with 2 tanks say the size of oil tanks that houses have in the garden for heating oil, the old metal ones.?

[Martin]

well, presuming that power production would be fairly much "pro rata" with my example, if you had a 1,000 litre tank, and you gave it a 10-12 metre head, it'd produce around 5 minutes @ 200 watts........ or roughly an hour at 16 watts - slightly less than you'd need to run an energy saving bulb for an hour...............

[Martin]

To put that in perspective, a 20w pv panel (at around £70) should supply that much current on average in winter, and around 6 times that in summer!

[Smooth Hound]

so it woulnt be a very viable thing then on a small scale, if it could be replaced with a 70w solar panel. but would be on a larger scale. oh well at least i know that now thanks for those calculations though, they give me a good idea of what would do what, if you see what i mean,

[snapdragon]

So who knows how much are photovolaics fitted ?? - in general sort of thing ? - seems like my old age savings might all be needed to put one up on my roof, along with solar water panels

am not capable of roof scrambling sort of diy and dragon does not do heights