Water Powered Cars

[herme3]

I've read that the technology exists to power a car with hydrogen fuel cells. I've even heard that successful prototypes have been created. Scientists claim that the problem with selling these vehicles to the public would be a lack of hydrogen, but I'm not sure how this could be a problem. Can't you just take water, and extract the hydrogen by using an electric current?

 

Why are we unable to power our cars with water? Is the technology just not ready yet, or is it physically impossible? Or, does it simply have to do with political reasons? I'm sure the government would lose a lot of tax money if everybody stopped purchasing oil.

[ecoli]

I've read that the technology exists to power a car with hydrogen fuel cells. I've even heard that successful prototypes have been created. Scientists claim that the problem with selling these vehicles to the public would be a lack of hydrogen, but I'm not sure how this could be a problem. Can't you just take water, and extract the hydrogen by using an electric current?

 

The chemical process is roughly the opposite of the one which the cars runs on, and thus requires energy.

 

Why are we unable to power our cars with water? Is the technology just not ready yet, or is it physically impossible? Or, does it simply have to do with political reasons? I'm sure the government would lose a lot of tax money if everybody stopped purchasing oil.

 

The reason is chemical. It is easy to combust oil, to release the energy in it's chemical bonds. How do you do this efficently with H2O?

[herme3]

The reason is chemical. It is easy to combust oil, to release the energy in it's chemical bonds. How do you do this efficently with H2O?

 

Read: http://www.howstuffworks.com/fuel-cell.htm

 

It sounds like the technology is available to power cars with hydrogen, but there is simply a lack of pure hydrogen. However, a science professor told me pure hydrogen can be extracted easily by running an electric current through water.

[Cap'n Refsmmat]

Can't you just take water, and extract the hydrogen by using an electric current?

Where do you get the electric current? You're just using hydrogen as another method of storing the energy you got somehow or another earlier. Most often, it would be fossil fuels->electricity->electrolysis (splitting water)->fuel cells, and that wouldn't be all that much more efficient than the current system, if at all.

[herme3]

Where do you get the electric current? You're just using hydrogen as another method of storing the energy you got somehow or another earlier. Most often, it would be fossil fuels->electricity->electrolysis (splitting water)->fuel cells, and that wouldn't be all that much more efficient than the current system, if at all.

 

How much of an electric current would be necessary? Could you obtain the energy for the current from a simple solar panel? The current would only need to extract the hydrogen from the water, it would not need to power the car itself. The hydrogen would power the car using the fuel cell technology.

 

According to http://www.howstuffworks.com/fuel-cell.htm the problem is not how to power the car with hydrogen, but instead obtaining the hydrogen required to power the car. Since water is such an abundant resource, wouldn't it be easy to just use the hydrogen that is contained within the water molecules?

[Cap'n Refsmmat]

It takes just as much energy to split water into hydrogen as you'd get from recombining hydrogen into oxygen again.

[Dak]

According to http://www.howstuffworks.com/fuel-cell.htm[/url'] the problem is not how to power the car with hydrogen, but instead obtaining the hydrogen required to power the car. Since water is such an abundant resource, wouldn't it be easy to just use the hydrogen that is contained within the water molecules?

 

like cap'n said: yes, but.

 

for a start, the energy required to split the water has to come from somewhere. easily doable at our current level of technology.

 

the bigger problem is this:

 

no one will make hydrogen powered cars without there being a developed hydrogen power infrastructure (ie, no petrol stations that also sell hydrogen = no hydrogen cars)

 

petrol stations wont start selling hydrogen, however, untill there is a demand, ie untill there are hydrogen cars.

 

Breaking this conundrum will probably require lots of govournment funding, essentially bribing petrol stations to stock hydrogen, and not taxing it for a good while to encorage people to buy hydrogen cars (then, when the demand is there, hydrogen cars will get made).

 

unless your talking about a car that you fill up with water, and then it's own on-board solar cells hydrolise the water and top-up its hydrogen tank, in which case the answre would be 'cos it'd be really expensive'. solar arrays are not cheap.

 

also, by having to let it recharge, youd be limited as to how many hours per day you could use it (the solar arrays would not split the water as fast as the hydrogen was burnt), although you could also produce pure O2, which i suppose you could add to the H2 to get a bigger bang.

[Cap'n Refsmmat]

for a start, the energy required to split the water has to come from somewhere. easily doable at our current level of technology.

Except that with our current level of technology, getting that energy would require fossil fuels somehow or another. The reduction in pollution would be minimal.

[herme3]

It takes just as much energy to split water into hydrogen as you'd get from recombining hydrogen into oxygen again.

 

The web site http://waterpoweredcar.com claims that using water to create hydrogen can already power a car, but I have a feeling that you are much more intelligent than the author of that web site. He thinks that secret government agents go around murdering people who attempt to invent water powered cars.

 

unless your talking about a car that you fill up with water, and then it's own on-board solar cells hydrolise the water and top-up its hydrogen tank...

 

Exactly. Do you think this would be physically impossible, or do you think the technology just needs to improve? For example, computers were once really expensive but now many people can afford them because technology has improved.

[Dak]

true, but we're moving towards more hippy power solutions, such as nuclear, or the ultra-hippy wind/solar/hydro power. in the uk at least, wind farms are popping up in quite a few places. (2% of UK power is green, going up to 10% by 2010¹

 

looking towards the future, the switch to hydrogen power would be good, to take advantage of any future, green energy sources. also, now it would at least get the pollution away from the people. if we are going to pollute, i'd rather it be done somewhere away from me.

 

one thing thats always concerned my about the idea of hydro powered cars: say you have a full tank and crash, rupturing your tank. wouldnt that be an almightily big explosion?

[Cap'n Refsmmat]

The web site http://waterpoweredcar.com[/url'] claims that using water to create hydrogen can already power a car, but I have a feeling that you are much more intelligent than the author of that web site. He thinks that secret government agents go around murdering people who attempt to invent water powered cars.

It's possible to power cars with HHO, but not H₂O (different bonding stuff involved). Converting H₂O to HHO, however, takes energy as well.

[Cap'n Refsmmat]

one thing thats always concerned my about the idea of hydro powered cars: say you have a full tank and crash, rupturing your tank. wouldnt that be an almightily big explosion?

Nope. Hydrogen dissipates rapidly, too rapidly for it to ignite, much of the time. I've watched a comparison of a hydrogen fuel leak and a gasoline fuel leak. The hydrogen just made a nice big tall flame (like you'd get from a blowtorch), while the gasoline spewed fire all over the place.

[CPL.Luke]

wierd I wasn't aware that you could bond two hydrogen's and an oxygen together in more than one way, because there is only 1 valence electron with which the hydrogen atoms can bond they can't bond to eachother while including the oxygen.

 

EDIT: I just looked it up, HHO is a blend of hydrogen gas and oxygen according to wikipedia

[SkepticLance]

According to New Scientist, it is possible to make a 'water powered' car, using boron metal as the energy source.

 

Works like this. Boron metal as a powder has steam passed over it. Reduces the water, leaving hydrogen gas, which runs the car, probably by a hydrogen fuel cell.

 

When all the boron is depleted, it is returned to a regenerating plant, which uses energy input (eg solar from mirrors) to reduce it back to boron metal to re-use.

[Sisyphus]

According to New Scientist' date=' it is possible to make a 'water powered' car, using boron metal as the energy source.

 

Works like this. Boron metal as a powder has steam passed over it. Reduces the water, leaving hydrogen gas, which runs the car, probably by a hydrogen fuel cell.

 

When all the boron is depleted, it is returned to a regenerating plant, which uses energy input (eg solar from mirrors) to reduce it back to boron metal to re-use.[/quote']

 

Definitely interesting, but doesn't it seem less practical than a simple fuel cell? Or maybe the advantage lies in the boron not needing to be replaced very often, and so the equivalent maintenance to fueling up is literally just pouring water in the tank...

 

Still, it's water + occasional boron vs. electricity..

[Dak]

Nope. Hydrogen dissipates rapidly, too rapidly for it to ignite, much of the time. I've watched a comparison of a hydrogen fuel leak and a gasoline fuel leak. The hydrogen just made a nice big tall flame (like you'd get from a blowtorch), while the gasoline spewed fire all over the place.

 

cool, and convienient.

 

Exactly. Do you think this would be physically impossible, or do you think the technology just needs to improve? For example, computers were once really expensive but now many people can afford them because technology has improved.

 

Oh, i see where your coming from now.

 

i dont think so.

 

i couldn't actually find any concrete figures, but if we over-generously assume:

 

average maximum solar power electrisity generation speed to be about 0.375kwh/h/m²¹, and say that you could squeeze about 1m²of solar cells on your car, then you'd generate 0.375kwh/h.

 

assume the car uses approximately 0.1kwh/mile²

 

assume 100% solar power conversion

 

youd get enough h2 to go 3.75miles every hour, or 90 hours every day. pretty sucky. not enough for many people, but not entirely unworkable i suppose.

 

however, thats if we make the above unrealistically over-generous assumptions (solar cells are waaaaaaaaaaaay off of 100% efficiency).

 

current solar power conversion efficiency is approx 15%¹, so i guess we'd be looking at about 13.5 miles/day.

 

i guess if everything was more efficient, it might be usable for light town use, or as a cool auto-refill feature on a car that can be manually refilled at a petrol station, but at our current level of efficiency, ie ~15% solar conversion, not really feasable.

 

(if anyone wants to tinker with the above calculations/assumptions, go for it)

 

notes:

 

i realise the above is a bit crappyly done

 

not sure what the efficiency of the theoryoretical 1kwh/m electric car is, so i'm not sure how much room for improvement is there

 

obviously, youd have to take into account that much less mileage would be gained in winter.

[CPL.Luke]

there are a few companies trying to do what is outlined above, I met someone who is now going to MIT at the connecticut state science fair who did experiments related to self production of hydrogen for use in internal combustion engines.

 

The general idea is that you convert a car to run on either hydrogen or gas (apparently its not that difficult to do) then sell them the means to produce hydrogen on their own. eventually a larger infrastructure will take hold because there would already be an established market for the hydrogen.

 

personally I'd go for a ~$500 kit that would produce enough hydrogen everyday to cover half of my driving.

[Sisyphus]

or as a cool auto-refill feature on a car that can be manually refilled at a petrol station' date=' but at our current level of efficiency,[/quote']

 

This could be a really great feature on a fuel-cell car. For one thing, it would be almost impossible to get stranded somewhere for long. You wouldn't be dependant on it, but the efficiency would increase the less you use the car. If you only use it occasionally or for short trips, you'd almost never need to plug it in.

[SkepticLance]

Sisyphus said :

 

Definitely interesting, but doesn't it seem less practical than a simple fuel cell? Or maybe the advantage lies in the boron not needing to be replaced very often, and so the equivalent maintenance to fueling up is literally just pouring water in the tank...

 

The main alternative to the boron plus steam idea is to use straight hydrogen. However, there are enormous problems with storage and transport of the gas. Trying to keep a tank full of gas in your car is both dangerous and wasteful. Hydrogen gas will leak out of the tiniest gap. Using boron metal makes the whole thing much easier.

[JesuBungle]

But in the Boron process, where does the steam come from? The water has to be heated somehow...

[CPL.Luke]

I would imagine that you could recapture some of the steam thats leaving the back end of the car after the burning process and run that over the boron again, I don't think this sort of fuel cycle could work as the boron water reaction is really supplying the energy to the system, not the burning of the hydrogen and oxygen.

[SkepticLance]

JesuBungle said ;

 

But in the Boron process, where does the steam come from? The water has to be heated somehow...

 

The New Scientist article said that the process would be started with a car battery. Just like current starter motors really.

[lucaspa]

Why are we unable to power our cars with water? Is the technology just not ready yet, or is it physically impossible?

 

We use gasoline because it combines with oxygen (a process known as combustion) and combustion gives off heat and forms a gas that expands. This expansion moves the cylinders.

 

Now, think about it. How is water formed? It is the end result of combustion! That is, water is formed by hydrogen burning with oxygen. Thus, all the heat has already been given off!

 

In hydrogen fuel cells, the end result is water. And electrolysing water takes far too much energy -- think of how much energy is given off in a hydrogen flame -- so separating the hydrogen and oxygen requires at least that much energy. Where does that energy come from?

 

Currently, the idea is to heat coal in the absence of oxygen so that hydrogen is given off. That will be the source of hydrogen in fuel cells. A problem is that this process gives off more pollution than burning gasoline in cars. The politicians like Bush who push the scheme hope you are too dumb to realize this. Yes, less pollution in cities where the fuel cells are used, but more pollution overall that comes from the plants making the hydrogen. Scientific American had a good article on this about 2 years ago.

[lucaspa]

looking towards the future' date=' the switch to hydrogen power would be good, to take advantage of any future, green energy sources. also, now it would at least get the pollution away from the people. if we [i']are[/i] going to pollute, i'd rather it be done somewhere away from me.

 

one thing thats always concerned my about the idea of hydro powered cars: say you have a full tank and crash, rupturing your tank. wouldnt that be an almightily big explosion?

 

1. Moving the pollution doesn't really solve anything, does it? Since it is atmospheric pollution, it is going to get to you eventually. What we need is fusion power. Then we would have enough cheap electricity to hydrolyze water for hydrogen. Until then, the current methods of cooking coal just makes more pollution.

 

2. There are ways now to keep the hydrogen bonded to porous metals -- titanium is one, I think. Thus, you don't really have a pressurized gas in a fuel cell like was in the bags of the zeppelins. No more danger of explosion than you have with gasoline powered cars -- maybe less.

[SkepticLance]

lucaspa

The coal to hydrogen approach is only one way of doing it, and as you said, not a smart way.

 

We can, however, make hydrogen from many sources. The cleanest is the electrolysis of water, if the electricity is generated in a clean way. eg. nuclear or wind.

 

I think this is the best way to use wind power. Simply hooking up windmills to electricity networks is not smart, since wind power is too variable. However, using wind power to split water to make hydrogen is much better. Make and store hydrogen when the wind blows. When it does not, use the stored hydrogen.