EddScott

Having asked the question of why don't we just use the heat from the earths core to run our powerstations, I have another question.

If water is made up of Hydrogen and Oxygen, why can't we use the Hydrogen as a fuel and have Oxygen as a waste gas?

Over to those that know more than I...

WRX_Dazza

because 10 months of the year there is a hose pipe ban

OllyK

Fine in places like Iceland where the magma comes close to the surface, in the rest of the world you need to dig down deeper than we currently have technology for. Add to that, as you go deeper the boiling point of water goes up and what you need at the turbine is steam, not hot water.

There are some small scale posibilities for a home owner using heat exchangers, but this is more for heating a house directly (IIRC) as it doesn't generate enough heat to produce steam and power a turbine.

The chemical bond between the Oxygen and the two Hydrogen atoms (in water) is very strong. The amount of energy you need to put in (usually electrolysis) to separate them exceeds what you get back when you burn it again. Hydrogen can be produced from other sources that are more energy efficent and indeed there is a lot of fuel cell research currently in progress to power cars, where the waste product is just water.

GazTheHat

I've got another couple of questions along the same lines, that seem so simple to me....

1) On TW ages ago, they had a small machine that turned sea water into water, seperating the salt.

If the world is gonna flood, why not have massive machine on the coast. We wont flood, there will be plenty of water. *ta-da*

2) Why not have solar panels in africa etc? They get loads sun, so there's loadsa missed energy.

OllyK

Sounds like some kind of de-salination plant. They are or were looking to use these in Australia due to the water shortages over there. They tend to be rather expensive affairs to get any significant volumes, although there are different methods such as osmosis and condensation.

As for the volumes of water, turning sal water in to drinkable water doesn't reduce the volume, you've got to find somewhere to store several billion litres of water, fine if you plan on turning Europe in to a reservoir.

Transportation of the power is the main problem, the resistance in several thousand miles of cable would be a major issue. However, sun is used in the desert in the US in places, but not usually normal solar panels. What I have seen is a whole series of mirrors focusing the light on to a tower containing salt. The heat generated is sufficent to melt the salt (several hundered degrees C IIRC). They then pump water round / through it, which is turned in to steam and drives turbines. I believe this is more efficient and cheaper than using photoelectric cells.

fivetide

iTrader: (1)

Photocells are a bit of a nasty item to make however -ignoring that and any compalints about cost etc, it doesn't take a lot to make a big difference. there is no real reason for example that each new build house in this country couldn't be fitted with a solar panel for heating or lighting use at night. It doesn't take that much sunshine.

5t.

GazTheHat

Well Olly, in the words of Pulp Fiction. "You're a smart motherfcuker"

GazTheHat

Completly agree with you Five.

Even increase the government grants on solar/wind turbine setups. That would solve loads issues.

I mean, if it was £500 for a solar setup and similar for wind, with 2-3 years to pay, who wouldn't be tempted!?!?!?!!!

I'm no do-good-er, i just don't understand why the solutions seem so simple, but get ignored.

OllyK

I know, it's enough to make you puke isn't it?

_Meridian_

iTrader: (1)

You can - what do you think a hydrogen fuel cell is? But the energy you get from recombining then is less than it took to split them apart in the first place. And splitting them is done with conventional energy. It's possible to use nuclear power to do the splitting of course.


M

OllyK

That's a slightly different issue and I would agree we could make better use of localised sun harvesting even in the UK.

OllyK

It used to be (IIRC) the pay back period was in excess of 15 years and the expected life (of photo cells) was less than 10. They have a tendancy for the efficiency to drop off quite dramatically with age. All this may have been improved over recent years, but algae growing on them still remains an issue as they need regular cleaning, which can be fun if they are on the roof!

GazTheHat

Nerr. Pretty impressive. Whilst i've got useless crap stuffed in my HDD, others have useful stuff.

Gotta admit though, i gave up with your other thread on morality. Ran it through my translator and got lots of errors. Think i only read & understood one post.

OllyK

That's assuming electrolysis.

Metal + Acid = Salt + Hydrogen is a more effective way.

Also catalysts can be used which make a difference, but they do tend to use expensive metals such as paladium or platinum.

GazTheHat

My other ideas shot down as well. Guess that's why it's not happened...

Brit_in_Japan

That's what I've been reading about too. Making mirrors is pretty cheap as it's old technology and should last a long time too (so long as there's not to many chav's around with stones ). The cost of mechanisms to keep them pointing at the energy concentrator will be something to consider and will present a maintenance overhead. The liquid salt can apparently be kept in well insulated tanks for days with little loss and released as required to generate electricity via steam turbines. Looks like it has potential

David Lock

Solar stuff is still relatively expensive, certainly for Africa. But I reckon in a few years China will knock out some affordable panels and it would make a big difference to rural communities for power - for water extraction for example and even to power radios/phones for communication and fridges to store medicines. Perhaps to power desal' plants on the coast.

Wind power in Africa also has a role to play as it can pump up water from rural wells overnight for drinking and irrigation. There are some quite good designs, crude but effective, that can be built locally although you do need a decent breeze to kick start them. dl

fivetide

iTrader: (1)

The differences in technology now i would think mean it isn't as much of an issue as it was. I mean, self cleaning glass anyone? Most new builds aren't exactly over hung by trees (usual cayse of alge) they are more likey to be over hung by each other!

I think with a proper scheme behind it the technology would contnue to improve. Like DVD. People were happy watching tapes, they didn't think there was a problem with the picture and the sound then whoo hoo! DVD and now high def. If the technology becomes mainstream it will only be improved atnd get cheaper.

Stairlighting in flats would eba good start and if it could sort you a full tank of hot water during the day so you can have a bath at night you'd surely be quids in with the electricity people!

Lots of issues of course but as you say Gaz... seems so simple!

5t.

Brendan Hughes

Saw an article about a real win-win one recently. I think it will be built in or near Morocco. Load of mirrors focussing on a tower which contains seawater. The water evaporates to cause steam to drive a turbine, but is then condensed to desalinated water to provide freshwater in a desert environment. I'm sure there were a ton of details I missed, but the principle sounded bloody clever.

Most use of water in our homes is flushing the loo. Rainwater for that is one thing (Olly, have you sorted that ISTR?), but I just caught a beeb prog on "dry toilets". Bit too eco-warrior for me though, still in the invention stages I'd say. They mentioned how popular they were, "20 000 sold last year in Europe". Hmm, among 400 million people - not my definition of popular.

Leslie

When they first got a nuclear power station working the papers were full of the fact that electricity would be so cheap that we would not have to pay for it!

Les

ScoTTyB

No true, they said it would be so cheap it would be unmetered. This was after nuclear power and was an attempt at an expreimental version they were referring too.

bugeyeandy

Ref the sea levels rising - why not build a giant tube that goes all the way to the vacuum of space. Fit a valve - when the levels are a bit high let some out into space.
Job done

p.s. Don't blame me if the valve sticks and we empty the atlantic

OllyK

Nope, hopefully a project for this summer, but we'll be using the water mainly for the veggie patch in case of hose pipe bans etc.

_Meridian_

iTrader: (1)

Except now you need energy to extract and purify the metal, and make the acid - which again leaves you with an overall energy deficit; probably a worse one.


M

kingofturds

iTrader: (1)

Let's build giant tesla coils and empty the ionsphere of electricity Free leccy for all and not just those pikeys with a fiddled leccy meter.

Leslie

Your memeory is better than mine then. I do remember the enormous headlines about it though, and for once it was not preceded by the word "Killer".

Les