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Comment by reactspa | Hacker News Reader

Can anyone please enlighten me on: Why isn't more being done to build out infrastructure related to Green Hydrogen?

It seems it just needs Water + Solar Energy.

One would think it would be the top priority worldwide.

The top priority is building enough renewables that storage begins to make sense. We're pretty far away from the point where it's cheaper to store energy as hydrogen than, for example, to make the demand side more responsive to changing supply. Until you literally don't know what to do with the oversupply you sometimes get from wind and solar, it makes little sense to throw a large part of it away to produce hydrogen.

Storage isn't the only reason to invest in green H2. It is e.g. the most plausible path for decarbonization of many industry sectors, including steel and chemicals. And these are often technologies that are in early stages.

I don't think this "first you need to do X, only then can you do Y" approach fits for the current situation. These technologies need to be developed now.

Developed now, yes, but built out later. Money is much better spent now on top-line renewable generating capacity.

Of course there are pilot electrolyzers, mostly for R&D. There are a couple MW worth in Germany for example. But there is no point in deploying them at scale until in makes economic sense. Until policy makes GHG emissions sufficiently expensive, nobody buys green hydrogen if natural gas is available.

In Europe a lot is happening, some companies are investing big into production capacities, see e.g.: https://blog.topsoe.com/haldor-topsoe-to-build-large-scale-s... https://www.westkueste100.de/en/orsted-en/ https://www.rwe.com/en/research-and-development/project-plan...

However one thing to keep in mind is that while extremely promising, green hydrogen is usually more expensive than gray hydrogen. (There have been some estimates lately with the high gas prices in Europe that this is different now, but that's of course only a very recent development.) So without policy support it's hard to make green Hydrogen happen. Unfortunately the US is still struggling to have any significant climate policy at all (thanks Joe Manchin).

Some would say there is actually TOO much being done with green hydrogen.

Hydrogen is very difficult to transport and almost all of the world's 90 million tons annual consumption is generated locally.

Hydrogen is a very sexy attracting a great deal of interest and investment and unfortunately distracting away from more straightforward decarbonisation pathways like electrification, smart grids and Closed-Loop Pumped Hydro Energy storage.

Hydrogen will have practically unlimited importance as feedstock for other processes, not limited to synthetic ammonia and methane, use refining iron ore and producing steel, and as liquid fuel for aircraft.

It's not a very good form of energy storage or transport. It's not dense either as a gas or as a liquid, so it'd be difficult to use in all the places gasoline, propane, etc. are used now. It also burns very hot in a combustion engine and causes nitrogen dioxide pollution in the process. It's a solution, sure, but not a great one.

I suspect it's inertia, and it's gradually disappearing.

Where I live proposals for projects like these are becoming almost common now:

https://infrastructurepipeline.org/project/central-queenslan...

https://www.industry.gov.au/data-and-publications/exporting-...

But go back 5 years or even 2 years, and the only exported energy projects bring proposed were gas fracking and coal mines. My, how times have changed.

It's simply because it makes a poor energy carrier.

You can also make methane from Water + Air + Solar Energy, and methane is a lot easier to deal with.

That needs a source of carbon.

That's what the air is for, you pull the CO2 right out of the air and use it for carbon.

CO2 is under 0.5%. Concentrating it is energetically expensive, although as energy cost continues down, cracking it may yet prove cheaper than mining and transporting CH4. Still, having concentrated CO2, it would be much better to fix it in a form from which it would not immediately be emitted back to the atmosphere, such as graphene, graphite fiber, nanotubes, or a polyester or polypropylene.

Most uses also need hydrogen. There will be a great deal of waste oxygen. That might best be dissolved into river water.

... under 0.05%, that is.

Electrolysis is very inefficient and other production methods are hydrocarbon-based which means you're just playing games with where the carbon is being released.

Hydrogen molecules are so small, it leaks out of everything, and leaks through a lot of things.

It embrittles a lot of metals.

It causes MEMS electronics to stop working.

Thanks. I thought you gave the most apt reasons.

Conventional alkaline electrolysis is about 70% efficient and PEM electrolysis about 80% efficient. That's pretty good. The round trip to electricity is of course worse, but hydrogen itself has many industrial uses.

Getting decent energy density requires thick walls and difficult seals at high pressure. Hydrogen leaks very easily.

Conveniently, ammonia is quite energy dense at atmospheric pressure or a bit above...

Where hydrogen is transported or used for fuel, it will be liquified and kept at atmospheric pressure; or stored underground at low pressure.

Ammonia is more practical for transport.

Blue hydrogen is cheaper. No one would buy green hydrogen.

Often said, but questionable if you want to have strict emission standards. The existing "blue h2" projects are abysmally bad, they only capture a small fraction of the emissions produced (see e.g. [1]). That you can run cheap blue H2 with low emissions - both upstream methane and CO2 that isn't captured, because CCS is never 100% - remains to be shown.

[1] https://www.energymonitor.ai/tech/hydrogen/shells-quest-blue...

Unfortunately very few potential buyers of hydrogen want to have strict emission standards right now.

Because liquified hydrogen requires more containment than gasoline and you need really clean water to make reasonable hydrogen.

AFAIK Nuclear is a lot better for this than PV anyways.

I'm in the "PV is greenwashing" camp, I worked for Solyndra, that stuff was d i r t y.

What did you do at Solyndra? I didn’t notice it listed on the resumé in your profile.

I was a subcontractor for a larger company.

Why are you generalizing relatively uncommon thin film solar panels to all solar panel types? I swear this is extremely common. People just say look these panels are bad, and nobody mentions that they are like 10% of the market at best.

Because they literally are all that bad.

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