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Comment by mey | Hacker News Reader

Energy storage into hydrogen always made sense to me. Would make vehicles more attractive. Could be converted back to energy later onto the grid when it was cost effective. Certainly not efficient, but it is still useful work.

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Hydrogen usually makes a lot of sense on a general theoretical level until you try it out. Consider that to get any useful work out of hydrogen you have to put it under high pressure. And if you put it under any pressure it leaks and seeps through any container, seeing how it is the smallest molecule known to man (or theoretically possible).

There are other ways to store electricity. You can store it into electrical heavy processes, such as making aluminum or steel from scrap. (Something that half researched blog post did not even mention).

Why does it need to be stored under high pressure? Compressing any gas is a waste of energy unless you have a need for those higher pressures, or space is an issue. If you're simply storing the hydrogen temporarily as a reserve, to later use for electricity generation, then storing it in large mylar bags, or silos at 8psi (close to isothermal expansion) or less seems the ideal way to go.

> then storing it in large mylar bags

May I suggest “Hindenburg” as a brand name?

Funny. Would you call an ice maker, Iceberg? Or name a generator after any of the fiery car or plane crashes?

I can assure you that hydrogen can be stored just as safely as other fuel sources. In many ways it is actually safer because it's escape velocity and the fact that it doesn't pool. Not compressing hydrogen would add to it's safety as there wouldn't be any stored forces to counteract, small leaks can be detected and don't cause turbulent ruptures.

Lithium ion batteries == spicy pillows

What few people note, is that during electrolysis of water, besides hydrogen you also produce oxygen. Oxygen is useful in gasification of organic waste products (corn stover, bigasse, and other woody biomass) to produce syngas that is not diluted by atmospheric nitrogen (a problem with using oxygen from atmospheric air). So not only are you producing hydrogen, which can later be converted into electricity or motive force (in a combustion engine), but also another form of fuel which can help to even out the energy needs when solar is not available. Up-cycling and recycling materials is a great use of excess electricity in my opinion.

Why not take this one step further? Surplus electricity produces green hydrogen produces conventional fuel using Fischer-Tropsch [0].

Not very efficient, but that would be an incredibly flexible green energy storage system.

[0] https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_proces...

there are relatively simple options for energy storage: lifting things up with the excess energy, then letting them back down if the energy is needed (at night). traditionally this is hydro, but it's also possible to do it with pulleys and concrete blocks.

edit: e.g. https://gravitricity.com/

I remember a similar concept that would work by stacking barrels of concrete using automated cranes. They had a press release like 2 years ago, and since then I never heard anything from them anymore.

The fixed costs of this are a problem, as the usual approach requires platinum electrodes.

The author points out that periodic negative prices for energy make inefficient processes a good use of capital, so no platinum required, just plain old electrolysis will be fine.

What is “plain old electrolysis”? If you do it carelessly, you risk producing the wrong outputs, and you also risk destroying your electrodes.

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