Underground Storage for Hydrogen

Hydrogen storage is problematic.

http://en.wikipedia.org/wiki/Hydrogen_storage

you must be kidding. that amount of hydrogen in such a tank is equal 1 gallon of diesel or 40 kw-hr of electricity. In the US thats about $5 worth of energy. A 1000 gallon tank will cost about $10,000.

Hydrogen storage is really tough. The very small size of a hydrogen atom (Free hydrogen exists as H2) allows it to pass through the interstitial spaces in most materials, including steel. Most rocks are slightly porous - meaning huge interstices and a ready path for hydrogen wanting to get out and join with oxygen someplace.

Just fill your tank with LP or CNG. It'll be more practical.

Hi Guest,

Where the hell are you getting the hydrogen from?

Spencer.

Spencer,

Well, the thought was to make Hydrogen from the solar collectors when the power was not needed to run the house. But, it doesn't seem practical YET from what I'm learning to date. And a much smaller tank would do if it was available.

Thank you all for your input.

Don't do it, Ethel!

Charge up a bunch of batteries instead, for safety and economic reasons!

Neat idea but I wouldn't do it if I were you. Are you making the H2 by electrolysis? That is a whole separate topic but thought I would ask.

Hydrogen is not a very good fuel, I will say that off the bat since I am assuming you would combust it. You would probably need to redesign your furnace so that it could handle the light gas. It will cost you more to produce it, contain it, and build it than it would save you.

You can get a 1000 gal tank very easily that will hold H2 at 40 psi, but I wouldn't do it even if I could get the tank for free. The changes to your heating system, gas detection equipment, regulators, etc. would be a significant cost. Then there is getting the H2 up to pressure to enter your tank and that would be an issue as well.

Your natural gas supply exists in inches of water column pressure and further has been odorized to help you find a leak. Note that some people still periodically lose their garages/roofs as a result of a natural gas leak. Storing hydrogen as you describe it could be putting a bomb underneath/inside your house.

H2 has an extremely broad flammability range and any leak would be a huge deal for the average residence. One of the benefits of H2 is that it is so light it tends to disperse quickly with a leak, but in your house it would just collect until your furnace or water heater kicked on and then it would detonate. If your low pressure H2 was contaminated with O2 before it was compressed into your holding tank, that would be a big problem as well.

Industrial H2 storage is starting to become a reality as more and more end users (refineries and the like) see it as a utility and source it out to other companies with high reliability requirements. Obviously there are already cylinders and high pressure storage trailers (you can see them on the highway here in TX). There are several operating H2 storage domes, but these are drilled wells in a salt formation that store the gas under several thousand feet of earth. The operating pressure of these wells would be two orders of magnitude greater than your question above to store enough H2 to make it feasible.

Thanks Much...! It looks like I/we have to work on new means for reliable safe storage before I ever will try to use it for home heating/cooking. Certainly, no building department will allow it until it has some form of safety sticker on it, and purity (no O2) is a very real concern it seems. And yes, I would have to pressurize it too which would use even more power, reducing my net gain. So, maybe someday, but not today I guess.

Hi Guest,

You have to remember that H2 has a tendency to migrate through almost anything, especially if it is under pressure!!! Pure H2 has a very poor calorific value and is as explosive as hell.

My advice to you is quite plainly, DON'T DO IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Spencer.

Store very carefully. Hydrogen embrittlement. Rust. don't put tank under your house and don't build anything over it. Check local codes make sure it's is an ASME Code vessel. .....Don't do it!

If making the H2 by electrolysis, you can use high pressure in your cell to avoid having to pressurize the resultant gas.

Storage is normally at around 5000 psi because the low density of the gas requires high pressure to get enough mass to be worthwhile.

As others have pointed out, the small molecule enables H2 to diffuse through almost anything. Very difficult to make leak proof joints.

I believe it is flammable from around 3% to about 96%, one of the broadest flammability ranges known. While this could have advantages for some uses, it also makes it dangerous to use. As it has no odor, there is no way of easily detecting a leak. A lighted match will do it but is definitely not recommended! (besides, the blue flame is almost invisible anyway)

In the future, your idea of using surplus photoelectric energy to produce H2 as energy storage could well be used, with the H2 being fed into a fuel cell when energy is needed, but I'm afraid that is not yet viable.

Unless your heating was to only use H2 and no other gases, the completely different jetting required would make it expensive and difficult to implement.

If you want heating, why not excavate for a rock pile, circulate daytime heat into it and reclaim it at night? This is simple and could be quite cheap.

Solar hot water is also a good energy saver.

If you want to store surplus photo electricity, normal deep cell batteries are still the cheapest way.