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Cheap, sustainable hydrogen through solar power

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Re: Cheap, sustainable hydrogen through solar power

#31

Post by fsh »

slow_typist wrote: post #24
defrost wrote: post #12

Earlier quoted context omitted.

> Just put it in a gas bottle. is a bit of an understatement. Consider that a household LNG gas cyclinder (propane if you're central north american I guess) is typically built to contain between 100 and 200 psi whereas hydrogen requires high pressure tanks to contain between 5,000–10,000 psi. That's a factor of 50 difference in required containment pressure capability.

And the hydrogen will still diffuse into the steel. And make it brittle so all bottles, pipelines etc have a limited lifespan compared to infrastructure for methane. And you always need pumps to get it from one containment into another because it stays gaseous all the time. Don‘t get me wrong, all these problems are technically manageable. But from the economic perspective the H2-hype is not reasonable at all. H2-app…

This is yet another misconception. Hydrogen embrittlement is due to atomic hydrogen being created in chemical reactions. Gaseous hydrogen consists of H2 molecules which do not lead to embrittlement [1].

[1] https://en.wikipedia.org/wiki/Hydrogen_embrittlement

Re: Cheap, sustainable hydrogen through solar power

#32

Post by philipkglass »

Schroedingersat wrote: post #27
defrost wrote: post #15

Earlier quoted context omitted.

Production is driven by demand and will very likely expand now that prices are rising again, just as production doubled back between 2011-2014 when last the price/kg rose [2] as it has in recent times. Annual Gallium usage includes a substantial amount of reclaimed material from electronics which isn't counted as production against reserve. > World primary low-purity gallium production capacity in 2021 was estimated…

Most rare elements are extracted primarily as side products. Scaling production directly is very difficult without demand for the co-occuring minerals.

Gallium is a side product of producing aluminum and zinc. Most processing of gallium-bearing raw materials for aluminum and zinc production does not currently incorporate any gallium separation stages. Current rates of gallium production can increase 5-fold without increasing rates of aluminum/zinc production or improving extraction techniques; current extraction techniques would just need to be deployed more widely.

See "On the current and future availability of gallium":

https://www.sciencedirect.com/science/article/abs/pii/S03014...

https://sci-hub.se/10.1016/j.resourpol.2015.11.005

Re: Cheap, sustainable hydrogen through solar power

#33

Post by defrost »

Schroedingersat wrote: post #27
defrost wrote: post #15

Earlier quoted context omitted.

Production is driven by demand and will very likely expand now that prices are rising again, just as production doubled back between 2011-2014 when last the price/kg rose [2] as it has in recent times. Annual Gallium usage includes a substantial amount of reclaimed material from electronics which isn't counted as production against reserve. > World primary low-purity gallium production capacity in 2021 was estimated…

Most rare elements are extracted primarily as side products. Scaling production directly is very difficult without demand for the co-occuring minerals.

Fortunately Gallium comes primarily from either bauxite (aluminum) or zinc deposits in more or less the same amount (~50ppm).

Ergo there's 50 tonnes of gallium per million tonne of bauxite, or 5,000 tonne of gallium in the annual 102 million tonne per annum bauxite production of Australia (alone).

These 5,000 tonne exceeds the current global demand for raw pure gallium by a factor of ten .. so it's not the demand for aluminum or zinc that's limiting global gallium production.

Re: Cheap, sustainable hydrogen through solar power

#34

Post by defrost »

philipkglass wrote: post #32
Schroedingersat wrote: post #27

Earlier quoted context omitted.

Most rare elements are extracted primarily as side products. Scaling production directly is very difficult without demand for the co-occuring minerals.

Gallium is a side product of producing aluminum and zinc. Most processing of gallium-bearing raw materials for aluminum and zinc production does not currently incorporate any gallium separation stages. Current rates of gallium production can increase 5-fold without increasing rates of aluminum/zinc production or improving extraction techniques; current extraction techniques would just need to be deployed more widely.…

snap! :-)

Re: Cheap, sustainable hydrogen through solar power

#35

Post by theshrike79 »

skrebbel wrote: post #14
theshrike79 wrote: post #8

Earlier quoted context omitted.

No, too many losses. Same problem with storage. Use isn't that expensive, fuel cells do exist. The problem with green hydrogen (made with electricity) is the inefficiency. It's only good for storage when you have already filled every battery and pumped hydro storage you have and are still making an excess. Electricity -> hydrogen -> electricity conversion is so hilariously inefficient that even petrol engines can bea…

I don’t understand that comparison. You can’t use electricity to make petrol, right?

Synthetic fuels can be created with electricity. But, again, the efficiency is laughable. The amount of energy lost in the conversion is so huge that it's not viable unless you've got crazy levels of overproduction.

But my comparison was about the fact that petrol engines convert only 20-30% of the energy in the fuel to actual motion - everything else is lost in friction and output as heat.

Toyota had a prototype engine that went up all the way to 35-37% efficiency, but it didn't make it to production.

Modern electric engines are 90-95% efficient.

Re: Cheap, sustainable hydrogen through solar power

#36

Post by xxs »

fbdab103 wrote: post #19

I am waiting for the day when there is an affordable ( Is anything like that on the horizon? Or do all of these liquid fuel synthesis options require industrial pressures/volumes/input electricity so as to forever be out of reach from residential synthesis?

10k is an absolutely wishful thinking - 10k is just the low end of a bog standard geothermal pump.

Also what's the purpose of the ethanol (the rest are not useful, esp. hydrogen which has to be stored somewhere, ammonia is rather dangerous)? I can imagine making vodka alike - but beyond that, using internal combustion engine to burn it means an extremely very low efficiency to conserve enegy. The energy density is there but the efficiency is not.

Re: Cheap, sustainable hydrogen through solar power

#37

Post by bamboozled »

DubiousPusher wrote: post #18

Is it just me or has it been like 18 months of one supposedly "game changing" hydrogen catalyst after another? I'm not trying to be cynical. It just seems the science press is awash in results from one research project after another in this area and I find it very difficult to rank which ones have any credible chance of utility.

I'm also sick of 18 months worth of negative comments about how hydrogen is a waste of time...

Re: Cheap, sustainable hydrogen through solar power

#38

Post by xxs »

kennywinker wrote: post #7
natch wrote: post #3

Is hydrogen cheap to transport, cheap to store, and cheap to use though? I thought making it was only a small part of the problems with hydrogen.

I mean, this doesn’t have to go into cars / be distributed widely… it could just used to time-shift solar energy to night time by burning it on-site. Which means you only need to solve the storage problem.

I doubt even 15% efficiency would be there; along with massive maintenance/size issues. Solar is cheap and easy when it comes to maintenance, effectively no moving parts. Internal combustion (or a gas turbine) is a whole new development... and there is the storage.

The best bet are still batteries, albeit the current incarnation of LiXXX (e.g. LiFePO4) are still not there. Even storing energy in batteries poses multiple conversions of electricity that goes to 92-95% efficiency.

Re: Cheap, sustainable hydrogen through solar power

#39

Post by adrian_b »

defrost wrote: post #15
Animats wrote: post #10

"The catalyst is made of indium gallium nitride nanostructures, grown onto a silicon surface." World gallium production is 400 tons a year. World indum production is 70 tons a year. How did "cheap" get into this?

Production is driven by demand and will very likely expand now that prices are rising again, just as production doubled back between 2011-2014 when last the price/kg rose [2] as it has in recent times. Annual Gallium usage includes a substantial amount of reclaimed material from electronics which isn't counted as production against reserve. > World primary low-purity gallium production capacity in 2021 was estimated…

The indium story is not similar.

Indium is one of the least abundant elements.

In the entire Solar System it is less abundant than gold.

In the crust of the Earth, it is less depleted than most other metals with high electronegativity (like silver and gold), so the result is that here indium has about the same abundance as silver.

Indium is completely irreplaceable in LEDs and in high-speed power transistors. The future demand for these two applications alone is severely constrained by the existing indium reserves (e.g. replacing all light bulbs and laptop/phone chargers and computer PSUs, in the entire world, with more efficient modern types would need a lot of indium).

Because of that, extreme efforts are needed to find substitutes for indium in its other applications, like for the computer displays, all of which currently use transparent electrodes made of doped indium oxide.

It is very undesirable to find new applications that would consume more of the scarce indium.

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