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What is Frozen Hydrogen?

Ken Black
Ken Black

Frozen hydrogen is the solid form of the common gas hydrogen. Scientists are interested in frozen hydrogen because it may be a potential fuel source which is more powerful than existing fuel sources. Already, liquid hydrogen has found a niche in the rocket fuel market. Currently, frozen hydrogen is still in the experimental phase and has no practical applications.

If frozen hydrogen is found to be a viable fuel source, scientists and engineers believe the potential power generated from liquid hydrogen would rival, if not far surpass, that of fuels currently in use. The advantage of frozen hydrogen is in its potential energy, per pound. Scientists at NASA believe that if it could be put to practical use, launches could occur with a mere 20 percent of the fuel weight currently required to achieve orbit. This also has the potential of allowing larger, heavier payloads and saving billions of dollars.

Frozen hydrogen is a solid form of the element.
Frozen hydrogen is a solid form of the element.

Freezing hydrogen is no simple task. In order to achieve frozen hydrogen, the gas must be cooled to very low temperatures. Liquid hydrogen, cooled to 14 kelvins (-435 Fahrenheit, -224 Celsius), is dropped onto liquid helium, and cooled to 4 kelvins (-452 Fahrenheit, -233 Celsius). The colder medium of the liquid helium causes the liquid hydrogen to freeze and float on top of the helium. It is when used together that both the hydrogen and helium have the potential ability to be used as a fuel source.

Russian rocket have been propelled by liquid hydrogen peroxide for decades.
Russian rocket have been propelled by liquid hydrogen peroxide for decades.

The energy to achieve propulsion comes after the helium and hydrogen is transferred to, and reheated in, the rocket’s engine. Physics tells us that as things cool, atoms begin to move slower and as things heat up, atoms speed up. In this case, once heated, the atoms would begin to move very rapidly and get even hotter. This also would produce massive amounts of energy, which would then be funneled out of the engine at an extremely high rate of speed, causing propulsion.

Some may be confused with what the difference is between frozen hydrogen and metallic hydrogen. The main difference is the form. Frozen hydrogen is a solid. Metallic hydrogen can, theoretically, be a gas, liquid or solid, although usually it is a gas or liquid. Metallic hydrogen is so named because when hydrogen is subjected to extreme pressure, it can display metallic properties. Because it is much more dense than ordinary hydrogen, it also has the potential of being a huge source of energy.

Discussion Comments


The conversion of both 14 Kelvin and 4 Kelvin into centigrade is wrong: the correct values are -259,15 and -269.15 C respectively


A pound of hydrogen whatever in liquid form or solid or gas has the same potential energy. The only relevant difference between those form of hydrogen is its volume.


@MrMoody - I wouldn’t count off hydrogen fuel cells just yet. Some time ago I read that Suzuki had released a hybrid hydrogen motorcycle already.

It’s a hybrid, so it uses an electric battery plus a hydrogen fuel cell. I guess since it’s a hybrid it doesn’t need a huge tank for the fuel cell. Maybe hybrids will be the way to go to transition over to hydrogen technology.


@SkyWhisperer - Well, I think that the hydrogen fuel cell car may still be a way off, perhaps further off into the future than you think.

However, I am a great believer in taking incremental steps towards new technologies. One such step in that direction is hydrogen gasoline, which is basically gasoline that has been spiked with a little bit of hydrogen to improve its fuel economy.

It’s still in the experimental stage now and you don’t see hydrogen gas stations popping up in too many places, but I think it’s more practical than hydrogen fuel cells.

The technology for hydrogen gasoline already exists. Basically a device in the engine will extract a small amount of hydrogen from the gasoline, and then add that hydrogen to the air/gasoline mixture during combustion.

This doubles the amount of air being used and improves fuel economy. Given the government’s increased regulations for improved fuel economy standards, I think this may be the best bet for using hydrogen to meet our energy needs.


I think hydrogen fuels hold promise for future energy needs, especially in the area of automobile fuel.

I don’t suppose that frozen hydrogen could be used in that capacity but I know that regular hydrogen would be. I’ve read that hydrogen fuel cells for automobiles have been developed as prototypes.

There is one large problem to date however. Hydrogen and oxygen need to be kept in separate tanks, and the tank for the hydrogen would have to be pretty huge from what I understand. So there is a minor logistical problem there.

Still, I have no doubt that they will overcome this problem and find a way to make hydrogen fuel cell cars a reality in the near future.

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    • Frozen hydrogen is a solid form of the element.
      By: viperagp
      Frozen hydrogen is a solid form of the element.
    • Russian rocket have been propelled by liquid hydrogen peroxide for decades.
      By: alex83ch
      Russian rocket have been propelled by liquid hydrogen peroxide for decades.