hydrogen cell submarine.?

Question

why dont nuclear subs make their own hydrogen and oxygen from seawater and use a hydrogen cell to propell themselves electricly for ever?

Answer 1

How do you propose to make the Hydrogen and Oxygen? It can be produced electrically or by certain chemical reaction but in either case you need an electrical source or reagents. So the basic answer is the longer term solution without refueling is nuclear.

However the limiting factor on a submarine deployment isn't the submarine its the food and the men. When a submarine leaves port food is stuffed everywhere, and I do mean everywhere. The men undergo extreme psychological testing to hold up under the conditions on a submarine but there are limits.

That said and knowing the fuel isn't the limiting factor the Germans have created a very functional hybrid submarine, U212 a type 212 submarine, that runs on diesel on the surface and uses a hydrogen fuel cell under water.

Answer 2

It takes energy to create hydrogen and oxygen by electrolysis. In a perfectly efficient cycle, that energy required is equal to the energy you get back when you fuel a hydrogen cell with the hydrogen and the oxygen you got from electrolysis. So transforming energy from the nuclear reactor to electrolyze water and then recombing it to get energy back gets you nothing at best. Worse still, it's impossible to be perfectly efficient. So the energy you get back will be less than the energy you used to electrolyze water. So if you just want energy, you are better off using the energy from the nuclear reactor to do work elsewhere instead of trying to transform it into hydrogen and oxygen to power another power plant.

Answer 3

They need a nuclear reactor to generate enough electricity to produce the hydrogen. Once they have that, why bother re-converting. They just use the electricity and steam from the reactor. Production of hydrogen takes energy too.

Answer 4

Too messy and complex. You'd have to distill the water first -- remember, it's salty. Building a fuel cell that puts out huge amounts of power would be a momentous task. Then you have to generate electricity to extract the hydrogen, then burn the hydrogen to make electricity to drive the ship motors... It's just not efficient.

Answer 5

Because a nuclear reactor is much more powerful and simple to maintain.
compared to a hydrogen system.

( they do make their own O2 )

Answer 6

To make hydrogen gas from water, you need a source of energy. There's no free lunch.

Answer 7

They do make oxygen from seawater! So you are half right!