No, it's not just a matter of technology, or at least not in ways that are readily addressable. Hydrogen molecules are so small that the simply pass through solid matter as if it were loose-weave cloth. Worse, it embrittles most metals.

And the leaked gas, especially if in an enclosed space, is flammable or explosive over a very wide range of concentrations.

Long-term storage, transport, and use, at scale, is hugely problematic.

https://www.sciencedirect.com/topics/engineering/hydrogen-mo...

https://en.wikipedia.org/wiki/Hydrogen_embrittlement

https://www.sciencedirect.com/topics/engineering/hydrogen-ex...

> And the leaked gas, especially if in an enclosed space, is flammable or explosive over a very wide range of concentrations.

So just have a small fan that constantly flows air around the container to remove all the leaked gas? They do it with heat from the batteries in EVs (which if heat up too much can explode). What is such a big deal?

If you have cheap enough energy that you're making hydrogen, can't you also make hydrocarbons? Granted, at the efficiencies we're talking, their only real use would be air travel (and petrochemicals, I suppose).

Yes. That's remarkable more sensible than futzing with naked hydrogen molecules, though the challenges here have been great as well.

I covered the topic in a series of posts based on then-new research about six years ago. That's ... not developed much further:

Primary article: https://old.reddit.com/r/dredmorbius/comments/22k71x/us_navy...

Others: https://old.reddit.com/r/dredmorbius/search?q=fischer-tropsc...

The main development since has been Foghorn, a Google (Alphabet) project attempting to develop the technology. It failed.

https://x.company/projects/foghorn/

What is the oil-cost-equivalent of existing synfuel technology?

(for uses such as air travel)

IIRC at $150 oil these synfuels were already competitive?

Varies by study, though upshot of the USNRL study wss that for net cost point-of-use (deployed carrier task force) it is competitive now (roughly $50-60/bbl cost of oil).

I'd argue that fossil fuel oil is grossly underpriced, by an order of about 10^6, but that's a longer discussion.

That seems to have the added benefit of removing CO2 from the atmosphere (many potential processes, according to wikipedia get carbon from the air).

> But I mean, that has to be a limitation of current technology, right?

Not much. Hydrogen has a tendency of assuming a form that no material can hold.

People have been working on chemical storage, but the efficiency always suffer.

Hydrogen has the nasty property of leaking through many materials, including metals. It also needs to be kept extremely cold. Both properties make it much harder to transport and store. It’s not clear that technology must exist that makes transporting and storing hydrogen as safe and economically viable as gasoline.

Even storage of helium has largely been solved, and that is far more tricky than hydrogen. It’s just expensive.

Helium is inert and not prone to explode when it sees the first spark. Also, as you indicate: storing helium is expensive - it is only economically viable because there is no competing product and hence whatever the price for helium storage is, it will get paid.

Remind me but there is also no way to make new helium. It’s not a renewable, is it?

I thought it was only available as a byproduct of natural gas collection.

If we ever figure out fusion, some forms of fusion result in helium.

If we ever figure out fusion, would this become a moot point or even more important than ever?

Safe probably yes. Economically competitive is much harder.