What's with this hydrogen fuel craze?

[ShawnD]

What's with this "hydrogen fuel" craze?

I heard something on the news about Iceland wanting to become entirely hydrogen powered. The reason being about reducing dependency on foreign oil.

Can anybody explain to me how this would reduce dependency on oil? Hydrogen gas is made from methane; the reaction is called the "water gas shift reaction" if you want to look it up. Methane, aka natural gas, is just as limited as oil. How does it benefit a country to switch over from limited resource A to limited resource B, if your country has neither A nor B, and resources A and B are both owned by the same group of people (middle east).

 

[Pengwuino]

Maybe they are using electrolysis... of coures where is the energy that poewrs electrolysis coming from.

And does it mean that everyone has to turn in their gasoline driven cars?

 

[zoobyshoe]

Hydrogen can be made many different ways, and making it by electrolysis of water using electricity generated by solar and wind power could make it a very clean energy storage system, indeed.

 

[ShawnD]

And does it mean that everyone has to turn in their gasoline driven cars?

I don't know about that. You can't really have hydrogen powered cars because hydrogen just doesn't have the energy. A tank of gasoline will drive you maybe 400km; that same amount of liquid hydrogen (which is impossible to create at any natural Earth temperature) would take you maybe 40km. Bigger molecules generally have more energy per unit volume, so diesel has more energy than gasoline, gasoline has more energy than propane, and propane has more energy than hydrogen. It would be wildly impractical to need to fill your car with hydrogen literally every day; including that hydrogen leaks out of the tank faster than you can imagine. If I'm not mistaken, hydrogen is the smallest nonplasma gas there is, so it's also the fastest leaking gas. If you've ever filled a balloon with helium, you would remember that the balloon just seemed to deflate itself in a short time. Hydrogen leaks out literally twice as fast as helium.
*spelling errors*

 

[Pengwuino]

Hmm... well they've had hydrogen vehicles down here for a few years...

 

[Ivan Seeking]

I heard something on the news about Iceland wanting to become entirely hydrogen powered. The reason being about reducing dependency on foreign oil.
Can anybody explain to me how this would reduce dependency on oil? Hydrogen gas is made from methane; the reaction is called the "water gas shift reaction" if you want to look it up. Methane, aka natural gas, is just as limited as oil. How does it benefit a country to switch over from limited resource A to limited resource B, if your country has neither A nor B, and resources A and B are both owned by the same group of people (middle east).

They have all the geo-thermal energy they need to make about twenty times more hydrogen than they need via electrolysis. They plan to eventually sell the rest.

We have been following the Iceland story for over two years in our Hydrogen threads
here
https://www.physicsforums.com/showthread.php?t=29373

and here
https://www.physicsforums.com/showthread.php?t=4127

 

[Ivan Seeking]

I don't know about that. You can't really have hydrogen powered cars because hydrogen just doesn't have the energy. A tank of gasoline will drive you maybe 400km; that same amount of liquid hydrogen (which is impossible to create at any natural Earth temperature) would take you maybe 40km. Bigger molecules generally have more energy per unit volume, so diesel has more energy than gasoline, gasoline has more energy than propane, and propane has more energy than hydrogen. It would be wildly impractical to need to fill your car with hydrogen literally every day; including that hydrogen leaks out of the tank faster than you can imagine. If I'm not mistaken, hydrogen is the smallest nonplasma gas there is, so it's also the fastest leaking gas. If you've ever filled a baloon with helium, you would remember that the baloon just seemed to deflate itself in a short time. Hydrogen leaks out literally twice as fast as helium.

you should do a lot of reading before you say any more.

 

[zoobyshoe]

How to carry the same amount of hydrogen as we now carry gas is a big part of the problem in developing hydrogen vehicles. People have been working on this for years and there's a couple alternatives to carrying it as a gas or liquid that have promise. Ivan had a huge long thread about it in engineering last year.

 

[Astronuc]

I don't know about that. You can't really have hydrogen powered cars because hydrogen just doesn't have the energy. A tank of gasoline will drive you maybe 400km; that same amount of liquid hydrogen (which is impossible to create at any natural Earth temperature) would take you maybe 40km. Bigger molecules generally have more energy per unit volume, so diesel has more energy than gasoline, gasoline has more energy than propane, and propane has more energy than hydrogen. It would be wildly impractical to need to fill your car with hydrogen literally every day; including that hydrogen leaks out of the tank faster than you can imagine. If I'm not mistaken, hydrogen is the smallest nonplasma gas there is, so it's also the fastest leaking gas. If you've ever filled a baloon with helium, you would remember that the baloon just seemed to deflate itself in a short time. Hydrogen leaks out literally twice as fast as helium.

By mass, hydrogen has a fast diffusion rate at a given temperature, but IIRC He leaks out faster the H₂ through a porous balloon. H storage systems are made of metal anyway, and there some metal relatively impervious to hydrogen, e.g. Re.

Ammonia, NH₃ is also fairly good storage medium for H, and it is usually cracked before use as a fuel. Of course, NO_x is still a problem.

 

[ComputerGeek]

I heard something on the news about Iceland wanting to become entirely hydrogen powered. The reason being about reducing dependency on foreign oil.
Can anybody explain to me how this would reduce dependency on oil? Hydrogen gas is made from methane; the reaction is called the "water gas shift reaction" if you want to look it up. Methane, aka natural gas, is just as limited as oil. How does it benefit a country to switch over from limited resource A to limited resource B, if your country has neither A nor B, and resources A and B are both owned by the same group of people (middle east).

Iceland is one big geothermal hot spot. They can harness that energy to electrolysis water for the hydrogen.

also, Nuclear power (thorium based) can be used as well to get off the dirty nasty oil.

 

[ComputerGeek]

I don't know about that. You can't really have hydrogen powered cars because hydrogen just doesn't have the energy. A tank of gasoline will drive you maybe 400km; that same amount of liquid hydrogen (which is impossible to create at any natural Earth temperature) would take you maybe 40km. Bigger molecules generally have more energy per unit volume, so diesel has more energy than gasoline, gasoline has more energy than propane, and propane has more energy than hydrogen. It would be wildly impractical to need to fill your car with hydrogen literally every day; including that hydrogen leaks out of the tank faster than you can imagine. If I'm not mistaken, hydrogen is the smallest nonplasma gas there is, so it's also the fastest leaking gas. If you've ever filled a baloon with helium, you would remember that the baloon just seemed to deflate itself in a short time. Hydrogen leaks out literally twice as fast as helium.

Perhaps the secret is to create synthetic hydrocarbons?

 

[ComputerGeek]

By mass, hydrogen has a fast diffusion rate at a given temperature, but IIRC He leaks out faster the H₂ through a porous balloon. H storage systems are made of metal anyway, and there some metal relatively impervious to hydrogen, e.g. Re.
Ammonia, NH₃ is also fairly good storage medium for H, and it is usually cracked before use as a fuel. Of course, NO_x is still a problem.

Isn't there a way to crack NH₃ without creating any NO_x?

could you hit it with electrons to split it in a chamber that does not have any oxygen in it so that it can not form NO_x?

 

[Astronuc]

Isn't there a way to crack NH₃ without creating any NO_x?

could you hit it with electrons to split it in a chamber that does not have any oxygen in it so that it can not form NO_x?

The cracked NH₃ produces H₂ and N₂. The problem is to separate N from H prior to the combustion chamber, which already has N as well as O from air. However, IIRC O is reduced more easily than N, and like combustion of natural gas (primarily methane), burning of ammonia produces less NOx than heavier fossile fuels.

NOx are handles with catalytic converters.

Perhaps the secret is to create synthetic hydrocarbons?

Fischer-Tropsch synthesis is a way to produce alkanes from H₂ and CO/CO₂, and there are a variety of FTS catalysts and processes.