T O P
  • By - ngt_

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Honigwesen

Today's pv cells have 20% efficiency. Assuming optimal 80% efficiency for electrolysis, this means 16% overall efficiency. So that is quite an achievement, if it's really low cost. (The image shows Platinum, so I'm skeptical on that)


jlaudiofan

Don't forget the titanium too, although the article says they are looking at replacing those with cheaper materials...


Bon2341

News tomorrow: ANU professor found dead with all research mysteriously gone.


notagoodboye

There are tons of problems with hydrogen as a fuel. It's almost impossible to store for any length of time (due to molecular size, it can squeeze past any seal), and it only has good energy density by weight, which means you have to store it at high pressures, which only exacerbates the problem of it leaking out everywhere. And since the only use of Solar->Hydrogen is energy storage and portability, which hydrogen isn't great at...Well, he's not going to be in any danger. If he made some kind of crazy hydrogen based battery or capacitor, that'd be different.


Aleksword

You can transfer hydrogen to ammonia and store it. Technologies for ammonia transport and storage arevery well knonw since its a major nitrogen fertilizer. And then you can transfer ammonia into energy.


vardarac

I was going to ask; if you can't seal the hydrogen, could you get it to bind to some kind of matrix. Chemically storing it is good too. What's the efficiency of binding and unbinding hydrogen to ammonia, though?


Aleksword

I don't have the exact numbers at hand, but in general ammonia can be synthesized from nitrogen and hydrogen via various methods, with the Haber-Bosch process currently the only method used on a commercial scale. The resulting ammonia can be easily transported, stored and the hydrogen can be extracted again at the destination via a thermal decomposition and separation process. Also, ammonia can also be burned directly in gas turbines in a mixture with natural gas or hydrogen. If ammonia is imported as a hydrogen carrier, burning it directly could eliminate the requirement for ammonia cracking (needed to reconvert it into hydrogen), thus removing an energy-intensive stage of the process.


jlaudiofan

What are the byproducts of burning the ammonia / hydrogen mixture?


jedify

Yeah, hydrogen economy is ill advised. However it can be used as storage for renewable grid stability. Or combined easily with CO2 to make methane. Or methanol. The Haber (fertilizer) process uses fossil methane to make H2 for ammonia. This could be a drop-in replacement with zero ghg emissions.


Alantsu

What happened to the fuel cells made of hydrogen absorbing metals? They were working on that like 15 years ago.


[deleted]

Probably run into the same sort of mass production issues that a ton of technologies (especially hydrogen) seem to encounter. Hydrogen’s a common substance and a bajillion experiments have been done with it, and there’s all sorts of fancy things you can do with an extremely light and reactive element, but not all of it is feasible to scale up.


Hypx

>There are tons of problems with hydrogen as a fuel. It's almost impossible to store for any length of time (due to molecular size, it can squeeze past any seal), and it only has good energy density by weight, which means you have to store it at high pressures, which only exacerbates the problem of it leaking out everywhere. Hydrogen can be stored in underground salt caverns for decades. You're creating imaginary problems here.


jlaudiofan

I don't think it's very practical to put an underground salt cavern in your car or airplane for hydrogen storage.


Hypx

He said it was impossible, which was way off. Also, carbon fiber tanks don't leak much either, so cars and airplanes can be powered by hydrogen without issue. The whole argument is one from ignorance. HFCEVs have been real-world practical for a few years now.


jlaudiofan

Actually, he said "almost impossible" and it makes me laugh that you say "don't leak much". I'm not ok with driving a vehicle that has a slightly leaky explosive gas tank.


Hypx

Even almost impossible is way off, since it's very easy and can be done cheaply. FYI, your gasoline car leaks gasoline vapors continuously. Hydrogen leaks at about the same rate, and you'll need to wait months before any noticeable loss of fuel.


jlaudiofan

Gasoline isn't flammable enough to ignite itself when mixed with air which apparently is the case with hydrogen. If you have a cheap and easy (and SAFE) way to store hydrogen please enlighten me because everything I have read so far is to the contrary. I'm all about alternative energy but all the proponents of it need to be honest about the cost and challenges associated with it.


Hypx

Since FCEVs already exist, and none of them have exploded in the way you're imagining, the counterexample is simple all of the hydrogen powered cars that already exist. What you've read is either wildly out of date or just anti-hydrogen propaganda.


jlaudiofan

I mean all I did was Google hydrogen safety and read a couple things. Wikipedia in particular, which also listed some hydrogen related incidents. Is Wikipedia out of date when it says hydrogen is difficult to store?


ScienceReplacedgod

Actually you are wrong [Not all fuel cell vehicles store their fuel as high pressure gas. ](https://i.imgur.com/1QRXGou.jpg) [Source Department of energy ](https://www.energy.gov/eere/fuelcells/hydrogen-storage-basics-0)


ShayShayLeFunk

I don't know what low cost means but this guy was doing it back in 2008. https://www.youtube.com/watch?v=Vel9LH57RII


timerot

This cell is notable because it's a high-efficiency system that converts sunlight to hydrogen directly, instead of going from solar energy to electricity via a standard solar panel, and then from electricity to hydrogen via an electrolysis.


ShayShayLeFunk

Thanks, working and didn't have time to read today. I guess that is the photoelectrochemical part.


jphamlore

> ... silicon/titanium/**platinum** photoelectrode Platinum scarcity is why fuel cells haven't taken off.


ScienceReplacedgod

We have enough for catalytic converters and fuel cell don't use platinum normally. Not having infrastructure to fuel hydrogen vehicles is much more the reason than platinum scarcity. Then there are many types of fuel cells. [Not all fuel cell vehicles store their fuel as high pressure gas. ](https://i.imgur.com/1QRXGou.jpg) [Source Department of energy ](https://www.energy.gov/eere/fuelcells/hydrogen-storage-basics-0)


pintord

Do you think existing pipeline infrastructure can be converted to hydrogen without too much cost, in other words it would be worth it? I am thinking after oil and gas, pipelines like Enbridge, will still have a market to transport fluids.


[deleted]

This technology is advancing pretty fast... maybe it can save us from extinction.