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Comment by Hypx_ | Hacker News Reader

The typical mono-si solar panel is about 20-22% efficiency. For poly-si this drops to about 15%, but are cheaper and therefore still sees a lot of demand. Solar water-splitting at 13.8% is well in the range of feasible competitiveness as long as it is cheap to build.

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Mono panels were 75% of the market in 2020, I read.

A concern I'd have with this water splitting is getting the water in and the hydrogen out (and separated from the oxygen). Wires are easier than pipes.

Doing this with ordinary PV also means the hydrogen production can be dispatchable. When PV output is tight, just stop making hydrogen and use the electrical power directly.

Keeping the hydrogen output separate from the water input and oxygen output is easy. You feed water in to the bottom of a U shaped container. You put the hydrogen-producing electrode in one half of the U and the oxygen-producing one in the other. The hydrogen and oxygen bubble up out of the water into separate collectors.

That only works with separate electrode systems; in-panel splitting (where the panel has a sheet of water directly over a catalyst) evolve both gases in the same place.

For larger installations pipes are easier than wires.

Why is that? I would guess solid-state (electrons in wire) is more reliable than moving-parts (fluids in pipes).

And it's easier to connect two wires than it is to connect two pipes.

All the little tubing collecting the hydrogen stream trickling out of these things seems like it would be a nightmare to create and maintain.

Over short distances sure, but once you're talking thousands of km a pipeline is way simpler.

That's nice, but it doesn't help the local collection network in the solar field. Using large separate electrolyzers driven by conventional PV lets you avoid that.

Unless the destination of the electricity is also next to the local collection network the pipeline can be simpler. It's certainly not going to be a worse idea.

You didn't understand what I said. I'm not arguing about a pipeline. I'm arguing about all the little hydrogen carrying piping in the solar field. This is needed to bring together all that hydrogen being generated at the hydrogen-generating solar collectors, before it even gets to a pipeline.

Simpler just to avoid all that and generate the hydrogen at large separate electrolyzers at the side of the utility-scale solar field (say), and then inject into the pipeline.

Should be noted that that will work too. In fact that is the plan for most facilities. However, you will still need a separate electrolysis facility. With this you just pipe hydrogen into bigger pipes. It could be cheaper to implement it this way.

For a household size connection sure, but once you're looking at extremely high voltages the electrical solution becomes hard. It's a totally different kind of cable and has very different problems to deal with. Meanwhile a pipe fundamentally doesn't change whether it's 1in or 48in wide.

The certainty with which you make all these obviously completely wrong statements is baffling.

Really, electricity distribution is a solved problem, and has been for more than a century. And here you are arguing that something that is in very minor use at the moment is 'easier', in spite of many challenges still be to solved before it can operate at scale. I'll just leave this link here and I would very much appreciate it if you stopped making all these assertions without qualification as though possess some kind of oracle because it is bordering on the ridiculous.

https://www.energy.gov/eere/fuelcells/hydrogen-pipelines

Your whole comment history is nothing but an endless stream of assertions without evidence including ones that are 'not even wrong'. That's not the level that I expect for this site and you are not doing us a service with this. I also do not understand why the only subject you are interested in is pushing the Hydrogen angle for more than it is worth.

Piping gases is also a solved problem. It existed even before electricity. I sound certain because I'm certainty right. If anything it's bit amusing to see supposedly smart people have so much trouble accepting the existence of 18-19th century technology.

FYI, coal gas is about 50% hydrogen and is two centuries old: https://en.wikipedia.org/wiki/Coal_gas#Composition

Nice to see ya posting around here. Always a pleasure.

I'm not as pro-Hydrogen as you but I see some potential benefits for sure :-)

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