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Cheap, sustainable hydrogen through solar power

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Re: Cheap, sustainable hydrogen through solar power

#111

Post by Schroedingersat »

imtringued wrote: post #45
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?

You do realize that the substrate is made out of silicon and that the thickness of the indium gallium nitride layer is only a few micrometers?

If you're looking at square kilometers of something made of indium you need to be talking nanometers not microns. Hence why it's just barely not a critical mineral for PV and why CIGS was a non-starter.

Re: Cheap, sustainable hydrogen through solar power

#112

Post by PaulDavisThe1st »

solraph wrote: post #104
PaulDavisThe1st wrote: post #89

Earlier quoted context omitted.

I live in New Mexico with a 6.7kW array. My house is heated with air source heat pumps. In the summer, we generate 3x the electricity we need. In the winter, we generate 1/3x of the electricity we need. Last year we generated 91% of all our electricity, the year before 93%. We would need a gigantic store for heating our house, because for 4-5 months a year, we are generating less electricity than we need. Something o…

15MWh of storage seems very high? I appreciate I don't know your raw numbers of production and consumption, but don't you still produce some power during the winter? ie; you would only need to cover your shortfall. For context, I live in the cloudy-ish south of Australia, and have similar problems with our solar power in winter. However, we still produce reasonable amounts of power through the day, and our total wint…

Our problem is not the shortfall in the winter generative capacity (sure, it drops a bit, but is still not far from 1MW/month). The problem is the increased load required for heating. I figure we need about 3MW/month for heat, for maybe 4-5 months, but you're right, the storage would only need to be 8-10MW, not 15MW since we'd still generate about 1MW anyway.

Re: Cheap, sustainable hydrogen through solar power

#113

Post by defrost »

Schroedingersat wrote: post #110
defrost wrote: post #33

Earlier quoted context omitted.

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…

Yes. I definitely meant the gallium alone and was not including the indium.

The wikipedia article on Indium: Production and availability [1] is ballpark okay and puts

> the supply potential of indium at a minimum of 1,300 t/yr from sulfidic zinc ores and 20 t/yr from sulfidic copper ores.

(ie potential max supply estimate as by product from mining other minerals)

This is almost double the current demand. Other industry reports are more optimistic than the source cited here in wikipedia but as a ballpark it'll do.

The wikipedia article has a decent description of one facet of the rare earth problem, that these elements are always bound up with other elements and are only economically feasible as by products.

The other great issue is the flip side of the same issue; they are bound to other elements and must be chemically seperated after mechanical pre processing .. and this can be lengthy, expensive, and leave acres of toxic waste to deal with.

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

Re: Cheap, sustainable hydrogen through solar power

#114

Post by adrianN »

cduzz wrote: post #101
adrianN wrote: post #85

Earlier quoted context omitted.

It's probably more efficient to centralize storing weeks worth of energy.

Many people in rural New England have or wish they had secondary power generation because you need that local energy more often when there are external events that likely also break the grid (big snow storm). The chain of events is "once in a gazillion century storm wipes power to huge region; millions of households are stuck without power, power company can't go out and fix all the broken things for weeks/months, ma…

Hydrogen storage is not particularly cheap either. I would be surprised if a house-scale system can beat batteries in terms of cost.

Re: Cheap, sustainable hydrogen through solar power

#115

Post by Schroedingersat »

defrost wrote: post #113
Schroedingersat wrote: post #110

Earlier quoted context omitted.

Yes. I definitely meant the gallium alone and was not including the indium.

The wikipedia article on Indium: Production and availability [1] is ballpark okay and puts > the supply potential of indium at a minimum of 1,300 t/yr from sulfidic zinc ores and 20 t/yr from sulfidic copper ores. (ie potential max supply estimate as by product from mining other minerals) This is almost double the current demand. Other industry reports are more optimistic than the source cited here in wikipedia but a…

If HSJ couldn't push extracting this extra Indium across the line due to lack of Indium whilst being better than PERC and TOPCon PV in every other way, it seems doubtful that one photocatalytic method out of a bunch can displace a PERC cell and an alkaline electrolyser that produce about the same amount of hydrogen per m^2 without the expensive vacuum deposition step.

More methods are always good though and hopefully the barriers to commercialising this method (or one of the others) have workarounds.

Re: Cheap, sustainable hydrogen through solar power

#116

Post by thomasmg »

youngtaff wrote: post #30
thomasmg wrote: post #6

Earlier quoted context omitted.

You can add hydrogen to natural gas (using existing pipelines and storage), and so slowly replace that. No changes to existing infrastructure needed up to maybe 20% I think.

You can but there are concerns about hydrogen being a smaller molecule so we’d get increased leakage (with knock on effects) No one really knows how our existing natural gas infrastructure will cope with hydrogen

Natural gas infrastructure already deals with hydrogen: 2% of natural gas is hydrogen. For town gas which was used before (made from coal), hydrogen content was around 50%, so this isn't entirely new. Of course you can't re-use the existing infrastructure and use 100% hydrogen.

This isn't black-and-white. Leakage is a disadvantage, as it is for fossil fuels (natural gas, oil, coal,...). Other technologies have other problems: windmills kill birds and bats! Pumped storage kills fish! Dams cause methane leaks! It is important to quantify how much of a problem those disadvantages really are.

Re: Cheap, sustainable hydrogen through solar power

#117

Post by thomasmg »

fungi wrote: post #53
thomasmg wrote: post #6

Earlier quoted context omitted.

You can add hydrogen to natural gas (using existing pipelines and storage), and so slowly replace that. No changes to existing infrastructure needed up to maybe 20% I think.

hydrogen worsens the impact of methane in the atmosphere and as such simply pumping hydrogen through existing infrastructure sounds pretty dangerous. https://theconversation.com/dont-rush-into-a-hydrogen-econom... https://agage.mit.edu/publications/global-environmental-impa... more skeptically, given that green hydrogen remains a pipe dream, it's both a useful delaying tactic for switching to electricity and furtheri…

Natural gas already contains hydrogen. Up to 20% of hydrogen in natural gas doesn't sound all that dangerous. The article you linked says "if a hydrogen economy replaced the fossil fuel-based energy system and had a leakage rate of 1%, its climate impact would be 0.6% of the fossil fuel system.". So the climate impact would be 100 times smaller(?)

Yes there are many delaying tactic for switching to electricity (the promise of "synthetic fuel" for example, to power existing gas cars). But using hydrogen to replace fossil fuels is needed anyway, for example for ammonia production and steel manufacturing. So I don't understand why you think hydrogen will delay the switch to electricity.

Re: Cheap, sustainable hydrogen through solar power

#118

Post by midasuni »

noogle wrote: post #70
midasuni wrote: post #66

Earlier quoted context omitted.

Why not just a 20kWh battery for energy time shifting. Or are you looking to sell the hydrogen?

This will last less than a day. What to do in the winter? If the answer is "use the grid", then we just kick the can to someone else, who will probably use fossil fuels to provide the energy. The basic problem remains - solar/wind are intermittent and fluctuating.

Compressed air has a higher round trip efficiency than storage, and pumped hydro is twice as efficient as compressed air.

However until zero kWh is generated from fossil fuels in summer, solar/wind and battery is a massive gain, even if gas is still used for 2 months a year.

Re: Cheap, sustainable hydrogen through solar power

#119

Post by midasuni »

fbdab103 wrote: post #98
ajross wrote: post #76

Earlier quoted context omitted.

The commenter's goal is presumably season-shifting, which is two orders of magnitude off from feasible battery capacity. In most areas in the US, a full-roof solar system will produce enough energy in aggregate to power the home's use year-round, but there's no way to get all those summertime watt-hours into the lines in winter when the panels are dark. But indeed, no, this just doesn't work. Best available efficienc…

No interest in storing a season's worth of energy which would be infeasible without a ludicrously over provisioned system. More -what could you do with spare capacity that is not trash-tier net metering? Generating liters of fuel weekly would be enough to power my ICE car (I rarely drive). Or being able to generate and store a ~week of liquid backup energy. Such a system would be unlikely to ever payback for itself.…

If you drive say 300 miles a week that’s 100kWh for a typical electric car. Another 150 for domestic use and that’s 35kwh a day. You have a system that generates more than that if you have excess to pump into liquid storage, but why do you want a weeks worth of backup energy? Why not 3 days? Or 2 weeks?

Re: Cheap, sustainable hydrogen through solar power

#120

Post by noogle »

midasuni wrote: post #118
noogle wrote: post #70

Earlier quoted context omitted.

This will last less than a day. What to do in the winter? If the answer is "use the grid", then we just kick the can to someone else, who will probably use fossil fuels to provide the energy. The basic problem remains - solar/wind are intermittent and fluctuating.

Compressed air has a higher round trip efficiency than storage, and pumped hydro is twice as efficient as compressed air. However until zero kWh is generated from fossil fuels in summer, solar/wind and battery is a massive gain, even if gas is still used for 2 months a year.

But gas is used also in the summer. And energy is not only electricity - heating is currently done mostly by natural gas, and is often absent from those calculations.

Efficiency is irrelevant. The only thing that matter is cost and feasibility. The cost of energy from solar is ~$0.02/kwh and sometimes even $0.00/kwh (when the grid curtails production). Even with 30% efficiency each kwh retrieved from storage will cost a record-low of $0.06/kwh (3-10 times lower than the consumer price).

The biggest factor here is the capex and ease-of-use of the equipment. Not the energy input cost.

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