using electricity to split water molecules (electrolysis) is almost certainly how we would create hydrogen for use as a fuel.

However, harnesing lightning is not all that practical. More popular ideas for methods that do not suffer the losses that 4.9 mentioned include wave farms and wind farms. These both utilise the earth's natural movements to generate power which can be used to produce the hydrogen.

But there's concerns that large windfarms can actually adversly affect the weather, due to the change in overall wind speed.

I had not heard that mentioned before, but it certainly makes sense. Global wind patterns are definitely not something we want to mess with.

I just had a semi-impossible brainwave.
The main problem with windfarms at the moment is to get any sort of meaningful power output you have to s**t of them, and put them in a windy place.
What about, and you can decide the best way to implement this (giant-GIANT towers perhaps?), having windfarms in high altitude jetstreams?
Is that pure hungover genius, or the vodka STILL making me look like a fool...

Ha ha hah ha ha ha. That's the funnyiest thing yet in this post.

So a bunch of big fans will slow the air down more than say a bunch of trees. Pull the other one. Were doing more damage to the environment driving our cars to work than a million windmills will do.

Anyway hydrogen itself is not the answer. Its like a liquid battery.

Use renewable energy to generate hydrogen by electrolosis. Transport the hydrogen (stored engergy) to a petrol (or hydrogen) station and then fill your car. Your car turns the hydrogen back to water, either by burning it directly or fuel cell and the process starts again.

100% renewable. Energy input is the sun, energy output is your car accellerating.

Saw it on telly some day a while back. Yeah, makes sense, but they couldn't provide any evidence of change.

You'd need almost a 10 year supply on each run..... if you can build a ship that can withstand those temps for a few months to suck off enough hydrogen.

Even harnessing it using a huge battery of batteries with lightning rods in knows areas of constantly high lightning activity?

I like that.... but the cost to produce enough 'buckey balls' just for one tower would be astronomical I would imagine.

Of course you'd have to use bucky balls because they have the highest tensile strength of any element known to man.... at least that was the case 5 years ago.

Fuel cells do not appear to be viable due to the requirement of platinum used as the catalyst in the process. Platinum is very expensive to mine and there isnt that much of it around. And as demonstrated by Mercedes, the dam fuel cell only lasts 200 hours before it's rooted(http://groups.yahoo.com/group/energyres ... sage/52194). We'd run out of platinum in a very short amount of time. Not to mention most hydrogen fuel cells cost about $1 million.

Which suggests that burning it would be the preferred option. Unfortunetely - it's not a dense fuel (at room temperature it takes up 3000 times more space than petrol containing the same amount of energy). To make things worse - it's an absolute bastard of a thing to store and you need to compress the hell out of it to be able to carry worthwhile amounts.

To have a tank size similar to what you find the average car, you would get 3kg of Hydrogen compressed @ 3000 psi. Unfortunately the tank required to hold this pressure would weigh about 400kg and cost $2,000 US dollars.

And after all that - you'd get a full 88km from the tank.

Ideally, you'd need liquid Hydrogen. Unfortunately at liquid form it's at minus 253 degrees celcius. Should make for a bit of fun at the bowser. Not to mention the insulation required on the tank.

So, all the free energy in the world which can be used to crack hydrogen from water... isnt going to be much good... because it's not a practical fuel. Sure, could be used for industrial machinery etc etc but not much good for personal transportation.

Seems John overcame quite a few obsticles during development of the water powered car.

Yes, john must have overcome a lot of obstacles.

Oxygen has a mass of 8 whereas hydrogen has a mass of 1. So, and excuse me if I'm wrong as I can't remember much of units 1&2 chemistry, a water molecule has a mass of 10. This means 20% of the weight of water is hydrogen.

So John reakons he got a V6 to idle for over a month on 50 grams of hydrogen.

He says that hydrogen has 6 times the explosive power of petrol. This throws up a few questions and some concern.

1. No-one want the charge in their cylinders exploding. Very bad. That's called detonation. You want a controlled burn. This may very well just be me being anal about the terminology John used, but if he's done what he says he's done, he'd be smart enough to use the correct terminology.

2. Can a V6 really idle for over a month on 300ml of petrol?

3. Exhausts are going to get more expensive aren't they?

Maybe waht people should be doing is looking for ways to make cars lighter and more efficient using fossil fuels, at least for the time being. If you can start producing cars with bodies made out of carbon fibre cheaply enough, and replace standard copper wiring with carbon nano-tube coated polymers, you drastically increase fuel economy. You might even be able to produce a Falcon that weighs in about the 750kg mark.

Now, if car companies can produce a family sized sedan that uses the same amount of fuel as a hyundai getz, the greenies would be happy at least for a little while..

The other thing that people don't consider is the sheer amount of fossil fuels that cars use compared to other vehicles/industries. I think private cars use about 1% of all fossil fuels. So how's eliminating that 1% going to help the environment when there's still 5000 passenger jets in the air at any one time carrying up to 550,000 litres of fuel? On 747-400 can carry up to 400,000 kilograms of fuel . That's 550,000 litres. That's almost 8000 full Falcons.

If every plane that takes off is carrying full, 550,000 litre tanks, that's the same amount of fuel that 40,000,000 family sedans use... that that amount of fuel is used in less that 24 hrs. That 40,000,000 cars would probably guzzle that fuel over a period of about a week.

Maybe well all scared Joh off with our talk of umm, you know, FACTS and not FANTASY.

Look at meee, I'm making people haaappy, I live in a gumdrop house on lollypop laaaaane.

BMW is releasing the first dual fuel hydrogen/petrol 7 Series early 2006.

It burns the Hydrogen in the engine a bit like LPG.

Also new fuel cells can be made without using platinum. They found some other thin film membrane or something that works the same way as a catalyst. This company made a fuel cell (including gas tanks) the size of a watch which would power a sensor for 100 years or something.

Fuel cells are in their infancy now but as soon as it becomes cheaper to use them instead of petrol - boom! development will increase dramatically.

Spork you beat me to it

I was going to say we better chop down our rainforests because all those tall trees are disrupting the wind patterns!

I'm interested in the energy return per windmill for those typical 3 blade ones when there is only average wind.

Also, with regard to the 3 blade windmills, does anyone else reckon they're extremely inefficient? I mean you have all that space between the blades where wind is passing and in my opinion that is wasted power. Look at most other windmill designs, they have dozens of blades and looking at the front you can't see through them from the number of blades. Sorta like a jet engine.

Why then do they use only 3 blade windmills when more blades would generate more power or am I missing something?

Why do piston engine aeroplaces only have 2 or 3 blades and not 20 or 30?

To use more baleds, you need a much larger hub to put all those blades in. If you increase the hub size, you reduce the blade length.

If you increase the hub size and want to keep the blade length the same, so have a few problems.

1. You probably have to make the tower taller so the blades clear the ground.

2. You're limited to the length of blade you use as you have to keep the tip speed below the speed of sound. Increase the blade length too much and in high wind conditions, your blade tips may exceed the speed of sound and become extremely inefficient.

3. More blades = more weight = more strength needed in the tower = higher production cost. If the wind machines cost 3 times as much to produce by using more blades, byt you only get a twice as much electricity, it takes much longer for the wind machine to pay for itself.