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Cheap, green hydrogen would be a breakthrough in clean energy

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Re: Cheap, green hydrogen would be a breakthrough in clean energy

#81

Post by ncmncm »

moralestapia wrote: post #60
chicob wrote: post #48

Earlier quoted context omitted.

I didn't know that. It certainly is safer. Ammonia production, as I already mentioned in another reply, currently requires natural gas as as source of hydrogen. Regardless of its use as a way of storing energy, it is already a very important industrial ingredient. Namely for fertilizer production. As I see it, the only major problem with the current technology is that it might not be adaptable to new sources. New pla…

My bet is on ammonia but yeah the economics will get tricky as producers are going to ask themselves "will I get more money if I sell this as fertilizer or as fuel?" Kind of what happens with corn-based bioethanol, where they have to compete with the regular food market and viceversa.

There is no natural upper limit on ammonia produced. Add more panels, make more ammonia. The panels, placed intelligently, do not use up land needed for other things.

Compare to bioethanol, strictly limited by acreage under cultivation.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#82

Post by ncmncm »

choeger wrote: post #43

There is, as far as I know, no fundamental physical reason that prevents us from having high-efficiency electrolysis and high-efficiency fuel cells. As an example (I did not try to corrobate the report) here is a company that claims 95% for the former: https://newatlas.com/energy/hysata-efficient-hydrogen-electr... So while it is true that current technology doesn't make hydrogen look like a viable option, improvemen…

Hydrogen is certainly viable, but it will take a long time to build out the equipment to produce enough of it. Every last kg produced will be spoken for.

Once LH2 aircraft enter any route, kerosene craft will suddenly be wholly unable to compete. But it needs abundant renewables, and synthesis equipment and underground tankage at airports.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#83

Post by ncmncm »

taneq wrote: post #67

The question isn't whether cheap, green hydrogen would be great to have. It's whether there is any physically possible world in which cheap, green hydrogen is better than cheap, green electricity in general. The problems with hydrogen aren't just absolute, they're relative.

We will need both. Given cheap, green electricity, there will be unlimited industrial market for as much cheap, green hydrogen as can be produced. And a very great deal will be produced.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#84

Post by lukeschlather »

kkfx wrote: post #57
chicob wrote: post #41

Earlier quoted context omitted.

Of course there is green hydrogen. First of all, the green aspect of it is that the source is renewable. That's what makes it green. It's not correct to call it a net loss, because no one wants to produce power from hydrogen in order to harvest more hydrogen. There would always be a renewable input somewhere. About losses. There are always losses on each energy transformation step. The same thing applies to electrici…

It's not a matter of efficiency but of scale: we can't produce enough hydrogen by hydrolysis even with all the electricity we can produce. On contrary probably we can made electric tools to substitute tractors. Something that demand a bit of investment but last FAR longer and can run only on p.v. the hard part there would probably be convincing farmers that they do not need tractors anywhere but only for very specifi…

This EU study suggests that we could produce enough hydrogen to fuel air travel with about 32 Pwh annually, which is maybe 20% of current global energy production. I am pretty sure your assertion is simply wrong. Converting to hydrogen would be expensive, possibly dramatically more expensive than other solutions, but it seems totally achievable.

https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202...

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#86

Post by ncmncm »

hannob wrote: post #42
oh_sigh wrote: post #9

Why are we all wrapped up with hydrogen when we already have a perfectly adequate hydrocarbon infrastructure? Sure, digging up old buried hydrocarbons and burning them isn't good, but couldn't we start synthesizing light hydrocarbons using green technology, so at least those usages are carbon neutral?

Sure we can, but a) all processes synthesizing hydrocarbons start with hydrogen, so you'll need cheap green hydrogen to begin with, and b) it takes a lot of energy.

Capturing CO2 to crack and attach to that hydrogen is itself expensive.

But there are places where nothing but hydrocarbons will do. Your old chainsaw, and all existing airliners, e.g. So, we will capture CO2, and turn some of it into hydrocarbons and re-exhaust it. Hopefully not most of it.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#87

Post by ncmncm »

kkfx wrote: post #50

I see exactly NO explanation about clean hydrogen production: - electrolysis demand so much energy that there is no point in using it, yes we can even use p.v. power to made hydrogen, only issue: with a large stadium of panel we can produce less than a pencil volume in H. Natural H reserves given it's atomic size sound a bit sci-fi to me; - since we can't store it safely we need to use it almost directly, witch is do…

I don't know where you get your facts, but they are all way, way off.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#88

Post by ncmncm »

moralestapia wrote: post #58
ravenstine wrote: post #20

Earlier quoted context omitted.

> separate it from water, which is a net energy LOSS This is true of every form of energy transfer. There is never, ever 100% energy maintained, and maybe you'll be stunned at how inefficient existing energy sources are.

I may be wrong about this but I recall reading it on a book about the history of energy. Anyway, supposedly around 99% (!) of the net energy of fuels gets lost from the source to your home. This due to energy conversion, loss in transmission lines, transformers, you own electrical installation, battery charging/discharging and other inefficiencies on the grid or the devices you use.

Losses are generally in tens of %. 99% loss is rare, maybe limited to AA batteries and food. Many of the calories we eat could in principle be converted to horsepower (e.g. biking), but are not.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#89

Post by pixl97 »

ncmncm wrote: post #73
perihelions wrote: post #72

Earlier quoted context omitted.

The downside is that ammonia is a heavier-than-air poison, like chemical weapons from WW1. Its hazards are significant. - "Anhydrous ammonia is lighter than air and will therefore rise (will not settle in low-lying areas); however, vapors from liquefied gas are initially heavier than air and may spread along the ground." https://wwwn.cdc.gov/TSP/MMG/MMGDetails.aspx?mmgid=7&toxid=2

We already synthesize and handle industrially millions of tons of it annually, and have done for going on a century. If there were a worrying problem with ammonia, you would already be hearing about it.

Heh, this is how I know you didn't grow up on a farm. You ever see a leaking anhydrous tank and you run for your life.

Re: Cheap, green hydrogen would be a breakthrough in clean energy

#90

Post by ncmncm »

kkfx wrote: post #53
ravenstine wrote: post #20

Earlier quoted context omitted.

> separate it from water, which is a net energy LOSS This is true of every form of energy transfer. There is never, ever 100% energy maintained, and maybe you'll be stunned at how inefficient existing energy sources are.

It's not a matter of efficiency but a matter of scalability: hydrogen generated by hydrolysis demand so much energy that we can't produce it on the needed scale, no matter how much it can cost. Methane extraction is absurdly costly, transport and storage are no less absurd BUT we can do it on a needed scale. That's the sole thing that matter. Similar if for hydro: mountain hydro is fantastic, we MUST develop it as mu…

It is not, in fact, the case that production of hydrogen is impractical. It will take time to build out electrolysis equipment. But you can buy it from China today.

And, given cheap storage, of course we can run passenger trains on renewables.

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