Cars running on water?

[Phaedrus]

According to this it's only a pipe dream.

It says,

We all know water cannot “burn” like traditional (fossil) fuels, but any hope of extracting energy from it at all, in some other way, can only be crushed by chemistry.

The thing is, we do use water as an energy source. Hydropower

My thinking is that the greedy gas companies don't want cars running on water because then they'd stop making money.

What say you? Am I wrong? Am I right? Educate me, you geniuses who know more than me.

[Minimalist]

There's this, from the US Dept. of Energy.

https://www.energy.gov/eere/fuelcells/hy...ectrolysis

[Thumpalumpacus]

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

[adey67]

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

Collect the oxygen too and feed it into the system to burn with the hydrogen and combustion would be augmented providing increased power but I don't see the point in using electrolysis to power a car you might just as well use the electricity directly.

[Thumpalumpacus]

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

Collect the oxygen too and feed it into the system to burn with the hydrogen and combustion would be augmented providing increased power but I don't see the point in using electrolysis to power a car you might just as well use the electricity directly.

I figured they'd put a generator on the engine to create further electricity in order to increase the engine's overall efficiency.

[Minimalist]

but I don't see the point in using electrolysis to power a car you might just as well use the electricity directly.

Range.  It is also a lot easier to fill a tank with water.  It seems to me that there is a lot of "down-time" with EVs while they are being recharged.

[Paleophyte]

The thing is, we do use water as an energy source. Hydropower

Your options are:

 - Electrolysis: As discussed, this is an energy in - energy out system. You use energy to split water into its component hydrogen and oxygen, then recombine them in the cylinders of your engine. The problem here is that you don't get any energy out that you don't first put in. Where you get that energy is the crux of the problem. What with thermodynamic inefficiencies it's simpler to just use the original energy to move the car than going through all these intermediary steps. Also, hydrogen is notoriously difficult to store and easy to make go boom in all the wrong ways.

 - Fusion: Currently beyond our abilities and it's probably inadvisable to built a car with a high neutron flux fusion reactor even if we could.

 - Steam power: We tried this. Like electrolysis it needs an external energy source and is prone to blowing up.

 - Indirect Hydro: In Canada we call this a Tesla. It's easy to generate hydro from large dams and power electric vehicles that way.

 - Direct Hydro: This conjures up some truly hilarious mental images of ways to get around this engineering nightmare. Your essential problem is the absurdly low energy density of water under any practical design. In principle, you can get the same energy density from falling water that you find in gasoline, you just have to drop it from about 5000 km up. Clearly that's going to pose some engineering problems, many of which will make NASA unhappy.

Using a more modest height of 10 m (who doesn't want a vehicle three stories tall?) requires a multi-million tonne water tank a few hundred meters on a side. Seeing as how you're now spending more energy to push the water around than you are to push your car your mileage is going to be rubbish, your acceleration a joke, and your turning radius a hazard to your entire neighbourhood. And you have the unenviable choice of either further crippling your performance by dragging around a second tank for your spent water or being a mobile environmental catastrophe that floods entire valleys as you drive past.

There is actually a workable solution to this problem and by "workable" I mean less horrifyingly broken than either of the previous crimes against engineering. The solution is to not carry you fuel source with you in much the same way that electric trolleys and subways do not. In principle, you could design highways with overhead aqueducts for fuelling and ditches for discharging exhaust water. Your car would need to syphon water from the aqueduct, extract the kinetic energy, and discharge the spent water into the ditch. The result would still be an abomination but at least physically possible. If any of you engineering types are up for it I'm pretty sure that actually building this thing would earn us an Ignoble Prize for demonstrating how horrifyingly impractical this would be.

[Cavebear]

I recall reading decades ago that the University of Maryland learned that mixing oil and water and extreme speeds resulted in a highly efficient combustible mixture for the steam-powered heating to the high-rise dorms. I wonder what ever became of that?

[polymath257]

According to this it's only a pipe dream.

It says,

We all know water cannot “burn” like traditional (fossil) fuels, but any hope of extracting energy from it at all, in some other way, can only be crushed by chemistry.

The thing is, we do use water as an energy source. Hydropower

My thinking is that the greedy gas companies don't want cars running on water because then they'd stop making money.

What say you? Am I wrong? Am I right? Educate me, you geniuses who know more than me.

Hydropower isn't extracting energy from the water as much as it is extracting potential energy by letting something (in this case, water) fall. Anything else falling with the same weight and from the same height would give the same amount of energy. In fact, there are energy storage *buildings* that take whatever initial energy source to lift weights. Then, when the energy is needed they let the weights fall.

Now, if you could heat the water, you could use it as a storage medium. if you heat it enough, you are essentially doing steam power. The problem is that you need to *keep* heating the water, which requires some *other* energy source.

The good thing about gasoline is that it can burn. It does so reasonably quickly, but in a controllable manner. It also gives off a  fair amount of energy per gallon. That is because it is a high energy compound. When it burns, it produces the low energy compounds water and carbon dioxide (assuming full burning and no additives). Notice that water is the end result after the energy has been extracted.

So, no, you can't use the water itself as a source of energy in the way you can with gasoline or other carbon rich chemicals. You can use the water as a storage device, but you have to produce the energy some other way and you still have issues of scale to deal with. For hydropower, the water is storing the energy of being higher in a gravitational field.

You are also not going to get energy out of sand, by the way.

[Dancefortwo]

Every time I see this thread I keep thinking of this car-boat thingy from the early 1960's which literally was "running on water".  The Amphicar.  

 

Hahaha.  I think this guy said it has a Triumph motor so I may post this over in Thingy's British export thread.

[mordant]

but I don't see the point in using electrolysis to power a car you might just as well use the electricity directly.

Range.  It is also a lot easier to fill a tank with water.  It seems to me that there is a lot of "down-time" with EVs while they are being recharged.

20% to 80% charge in about a half hour at a level 3 charger, roughly. However, in real world use cases (virtually all commuter and regional driving even in EVs of moderate range) it's actually fine to trickle charge it on 115 V / 12 W overnight. In that mode, 12 hours of charging provides about 36 miles of range, which is more than most people drive locally in a day. I start out at about 190 miles range, let it drift down to as low as 40 miles, and THEN charge it over the next couple of days. In practice I do this every 2 weeks, if that. As a bonus, gentle charging extends battery life and efficiency.

People in a little more of a hurry can spend a few hundred for a level 2 charger (220 V / 50 W) which will give you about 120 miles of range in 12 hours of charging. There are a lot of these in most cities, too, on networks like ChargePoint. Many are provided free by shopping malls and grocery stores to encourage you to spend $ there.

The problem is long road trips. For that IMO you need at least an EV with a 300 mile range, and really preferably, some 2030 model that's not yet available with a 500 to 750 mile range that can recharge in a few minutes. The technology is coming along. Level 3 fast chargers are actually more plentiful than you'd think, just not as obvious as gas stations. You find them with apps, not by looking for tall signs on the Interstate. Many car dealers also have them for customers, and many of those don't charge for the electricity.

Several battery formulations are coming along nicely such that I expect our current arrangement (one modest-range EV hatchback and a conventional small SUV for road trips and hauling dogs around) will give way to a single EV by the end of this decade.

[mordant]

duplicate

[Thumpalumpacus]

The problem is long road trips. For that IMO you need at least an EV with a 300 mile range, and really preferably, some 2030 model that's not yet available with a 500 to 750 mile range that can recharge in a few minutes.

Sorry for the tardy response.

Modern ICE cars average between 280-400 miles per tank, and that's been the case for at least three or four decades; so that is the consumer expectation. Now, if you can bring recharge time down, as well as expand the infrastructure to do so, that would seem a much easier push than charging for 500-750 miles, which consumer don't expect anyway.

Yes, you may have to build that range in initially while infrastructure is being built, which will certainly limit the market penetration of those models due to expense. But as charging stations increase in number and capability, you can dial down on-board energy storage again and wind up with a much more affordable vehicle, I imagine.

[Minimalist]

How long does it take to recharge an EV?

[rocinantexyz]

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

Right, that is super important. People seem to fail to understand the very basic idea that if you get X energy released when you snap molecules A and B together, then it will take AT LEAST X energy to separate them later. And you will need to separate them later if you want to repeat the process (either that or you have to pour in "pre-separated" molecules you got from somewhere else, aka: fuel).

Anyway, it is nice to be somewhere were people live in the real world.

[Thumpalumpacus]

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

Right, that is super important. People seem to fail to understand the very basic idea that if you get X energy released when you snap molecules A and B together, then it will take AT LEAST X energy to separate them later. And you will need to separate them later if you want to repeat the process (either that or you have to pour in "pre-separated" molecules you got from somewhere else, aka: fuel).

Anyway, it is nice to be somewhere were people live in the real world.

There is no magic wand. There is no god who will save us from ourselves. There is no getting around the laws of physics. Creating energy will never be 100% efficient. And the input for startup and continuation will produce side-effects we may not have considered.

Welcome aboard. I'm a Rush fan, I originally read your screen-name as "Rocinante YYZ".

[Chas]

It is not now, nor was it ever, possible.

It vciolates the first and second laws of thermodynamics.

Think 'cold fusion'.

[no one]

Maybe I'm a little wet behind the ears, but if this gains some steam, perhaps these vehicles will reign supreme.

[Sunflower]

According to this it's only a pipe dream.

It says,

We all know water cannot “burn” like traditional (fossil) fuels, but any hope of extracting energy from it at all, in some other way, can only be crushed by chemistry.

The thing is, we do use water as an energy source. Hydropower

My thinking is that the greedy gas companies don't want cars running on water because then they'd stop making money.

What say you? Am I wrong? Am I right? Educate me, you geniuses who know more than me.

Separate the hydrogen from water with electrolysis (iirc), burn it for energy, its waste is water, recapture that exhaust ... but that pesky 2LoT will get in the way.

Collect the oxygen too and feed it into the system to burn with the hydrogen and combustion would be augmented providing increased power but I don't see the point in using electrolysis to power a car you might just as well use the electricity directly.

Hydropower relies, not so much on water itself but rather the potential energy provided by gravity being converted into kinetic energy as it falls from a height, then converted into mechanical, then electrical energy by a hydro turbine and generator respectively.

So unless your compact car can fit a hydroelectric dam onboard, hydropower (at least onboard hydropower) will not work.

Water can be separated into its subcomponents, hydrogen and oxygen, vis a vis electrolysis, but this quickly runs into a conflict with the First and Second Laws of Thermodynamics.  Under perfect conditions, you will need to at least input the same amount of electrical energy into splitting water into hydrogen and oxygen molecules as you will get from the chemical energy emitted from burning the hydrogen and oxygen again to produce water.  As H2 has an energy density around 110 MJ/kg, that's going to be a whole lotta electric power.

Hydrogen also has to be stored cryogenically as a liquid for best storage and has a very low density. As a result its difficult to store the stuff aboard a vehicle.

Water, or at least heavy water (D2O) can be separated into deuterium and oxygen, then the deuterium could undergo thermonuclear fusion to produce power.  Here's the catch: we have yet to produce a thermonuclear reactor that 1) yields a sustainable net positive output of energy, yet 2) is small enough to fit into a car and 3) does not require several thousand tons of concrete and lead shielding to prevent the radiation during operation from killing everybody in the car as well as nearby motorists and pedestrians.

No free cup of coffee in this world.  Mother Nature saw to that.....

[rocinantexyz]

Welcome aboard. I'm a Rush fan, I originally read your screen-name as "Rocinante YYZ".

Cygnus X-1 Book 1 and 2? Well I don't plan on flying into any black holes. .

[Thumpalumpacus]

Welcome aboard. I'm a Rush fan, I originally read your screen-name as "Rocinante YYZ".

Cygnus X-1 Book 1 and 2? Well I don't plan on flying into any black holes. .

I just figured few knew the original from Don Quixote and you named yourself after the sci-fi musical mule.

[Kim]

Ok so, no hydrogen run cars.  

How about trains? "They have a range of 1,000 kilometers (621 miles), meaning they can run for an entire day on the network on a single tank of hydrogen.". And ... "The trains can go at a maximum of 140 kph, or 87mph, though regular speeds on the line are much less, between 80-120 kph.".
Out here in the boonies, we could sure use these passenger trains. I drive 50 to 80 miles away once a week just to get groceries I can't get where I live.

[Sunflower]

Ok so, no hydrogen run cars.  

How about trains?  "They have a range of 1,000 kilometers (621 miles), meaning they can run for an entire day on the network on a single tank of hydrogen.".  And ... "The trains can go at a maximum of 140 kph, or 87mph, though regular speeds on the line are much less, between 80-120 kph.".
Out here in the boonies, we could sure use these passenger trains.  I drive 50 to 80 miles away once a week just to get groceries I can't get where I live.

Short answer: yes, but why would you want to?

Given that a train runs on a set of steel rails close to the ground it’s much easier simply to provide electric power to it from the main electrical grid via the overhead powerlines or an energized third rail. The train can simply make contact with that or via magnetic induction and get its power that way, there by eliminating the need for a hydrogen powerplant onboard the train.

[Thumpalumpacus]

Ok so, no hydrogen run cars.  

How about trains?  "They have a range of 1,000 kilometers (621 miles), meaning they can run for an entire day on the network on a single tank of hydrogen.".  And ... "The trains can go at a maximum of 140 kph, or 87mph, though regular speeds on the line are much less, between 80-120 kph.".
Out here in the boonies, we could sure use these passenger trains.  I drive 50 to 80 miles away once a week just to get groceries I can't get where I live.

Short answer: yes, but why would you want to?

Given that a train runs on a set of steel rails close to the ground it’s much easier simply to provide electric power to it from the main electrical grid via the overhead powerlines or an energized third rail. The train can simply make contact with that or via magnetic induction and get its power that way, there by eliminating the need for a hydrogen powerplant onboard the train.

I'd imagine the grid is getting ready to be swamped by electric cars and there's that air-conditioning draw from global warming too. Perhaps these rail companies want to steer clear of fighting for the energy to go from Point A to Point B?

[Sunflower]

Ok so, no hydrogen run cars.  

How about trains?  "They have a range of 1,000 kilometers (621 miles), meaning they can run for an entire day on the network on a single tank of hydrogen.".  And ... "The trains can go at a maximum of 140 kph, or 87mph, though regular speeds on the line are much less, between 80-120 kph.".
Out here in the boonies, we could sure use these passenger trains.  I drive 50 to 80 miles away once a week just to get groceries I can't get where I live.

Short answer: yes, but why would you want to?

Given that a train runs on a set of steel rails close to the ground it’s much easier simply to provide electric power to it from the main electrical grid via the overhead powerlines or an energized third rail. The train can simply make contact with that or via magnetic induction and get its power that way, there by eliminating the need for a hydrogen powerplant onboard the train.

I'd imagine the grid is getting ready to be swamped by electric cars and there's that air-conditioning draw from global warming too. Perhaps these rail companies want to steer clear of fighting for the energy to go from Point A to Point B?

How far simpler solution would be to increase the capacity of the electrical power grid by building more power plants. That would take care of the problem far faster than going over to hydrogen powered trains.