OT Posted on Facebook Solar Electric to Hydrogen

[Tundra Twin Track]

That sounds safe in an accident! My chemistry ain't great, what's the advantage of burning compressed gaseous ammonia (NH3) instead of H2?

NH3 is stored in exact same tanks as Propane,Brass Fitting for Propane and Steel Fitting for NH3.There’s been a few Propane Vehicles out there in the last 60 yrs.
I know nothing about H2,just mentioned another alternative that sounded interesting that conversion’s are cheap and can still run on gasoline,he mentioned NH3 was
25 cents a litre.

[SLK001]

I heard a story from the guy who inspected my car the other day. He says he read that if you tow a Tesla with a Tesla it recharges the towed car faster than the tow car uses electricity. So in theory you can drive forever free by just switching positions. I guess you just have to buy two Tesla's.

That's BS. It would violate the law of conservation of energy. In essence, it would be a "perpetual motion" machine.

[gellfex]

NH3 is stored in exact same tanks as Propane,Brass Fitting for Propane and Steel Fitting for NH3.There’s been a few Propane Vehicles out there in the last 60 yrs.
I know nothing about H2,just mentioned another alternative that sounded interesting that conversion’s are cheap and can still run on gasoline,he mentioned NH3 was
25 cents a litre.

I was thinking more about the poisonous aspects of it than the explosive. A ruptured propane tank would not kill everyone within it's spread radius, even if it ignited.

[gellfex]

Well, you might not HAVE TO waste as much energy as you think.

Out of my expertise, but isn't storing less than liquid O2 inefficient, and storing liquid logistically immense? Hard to imagine a vehicle with 2 pressure tanks!

I'm an optimist, at least when it comes to tech, I think the battery problem will be solved one way or another, even if it means government mandating an interchangeable battery standard (which we should have for the damn cordless tools!) The IC engine is dead tech rolling.

[wmgeorge]

Batteries are getting better and lighter. I have now 3 LiFePO 12.8 volt 100 AH and they weigh 29lbs each. Going on my solar PV system. Stay charged for 6 months, no acid no fire hazard.

[Rich Carlstedt]

Batteries are getting better and lighter. I have now 3 LiFePO 12.8 volt 100 AH and they weigh 29lbs each. Going on my solar PV system. Stay charged for 6 months, no acid no fire hazard.

Wow that is some incredible statistics
But at $1,200 for one battery ( takes four at 3.2V) it's a bit on the high side !

https://www.ebay.com/itm/19426956284...4bd757e6720bf0

Rich

[J Tiers]

Out of my expertise, but isn't storing less than liquid O2 inefficient, and storing liquid logistically immense? Hard to imagine a vehicle with 2 pressure tanks!

...............................

It's likely no worse in that way than storing hydrogen. The problems are in reactivity with so many substances, as was found out the hard way years ago.

Hydrogen boils at a very low temperature, about 20K, oxygen at about 70K higher. Neither of them are very good for liquid storage, and oxygen is O2, meaning that you only need half the "molecules" of oxygen vs H2.

I'd rate it as not terribly practical at the moment. But, it gives the possibility of getting much closer to the efficiency Carnot will let you have. Likely worth a good look, if one is determined to try to use hydrogen.

Personally, I would rate liquid fuels as far better. Making fuel from algae is probably far better, as you utilize the sun directly, through a fairly optimized biological system, the fuel is a liquid, so it can be handled by existing infrastructure, and a relatively direct path exists from algae to fuel in a plain sheet metal tank.

So many of these schemes seem like the metric system...... they appear to be designed to be different from, and incompatible with, every other option, and everything that has gone before. One really needs to see that they have an overwhelming advantage to make them desirable.

Batteries are getting better and lighter. I have now 3 LiFePO 12.8 volt 100 AH and they weigh 29lbs each. Going on my solar PV system. Stay charged for 6 months, no acid no fire hazard.

Gasoline is about 13kWh /kg. The battery you cite, per your numbers, stores about 1.3 kWh, in 13 kg, which is approximately 0.1 kWh.kg. A factor of 10 difference.

Maybe you meant to type 1000 Ah, or 2.9 lb, I don;t know. At 1000 Ah, it would be competitive with fuels, but I suspect that is not the case.

OK, a Trojan T-105 holds 250 AH at about the same voltage. It weighs about twice as much, no issue for a stationary solar setup.

"no fire hazard".... well, that depends. I would say that they pose at least as much fire hazard as any battery does.

[Tundra Twin Track]

I was thinking more about the poisonous aspects of it than the explosive. A ruptured propane tank would not kill everyone within it's spread radius, even if it ignited.

Agreed I’ve been around NH3 for years and it can be nasty stuff!I know little about H2 and seems storage issues are a problem with it,who knows where things are headed but I’m sure Power Shortages will be a major issue going forward.I’m betting people won’t be happy turning there heat or AC off to be able to charge there car.

[CalM]

I wonder if a practical H2 to CH4 (Methane) conversion could be put into the mix Methane is easily stored with a water seal.

[PStechPaul]

The figure I found for gasoline is 44 MJ/kg, or 12.2 kWh/kg. At about 25% efficiency in the usual ICE, that is effectively about 3 kWh/kg. For an EV with lithium batteries at about 0.15 kWh/kg, and 90% efficiency, the ratio of energy density is about 20:1. The energy density of LiFePO4 chemistry is typically somewhat lower, so the calculated 0.12 kWh/kg is about right. The same source shows hydrogen to be about 121 MJ/kg, or 33.6 kWh/kg. Of course, the pressurized containment vessel for liquefied hydrogen would be much heavier than that for gasoline, so that would need to be taken into account.

As for ammonia as fuel for ICE, it appears possible but problematic:

https://www.ammoniaenergy.org/topics...ustion-engine/

https://www.sciencedirect.com/scienc...60319920300124

https://www.energy.gov/sites/default...combustion.pdf

[gellfex]

I wonder if a practical H2 to CH4 (Methane) conversion could be put into the mix Methane is easily stored with a water seal.

If you're going to rectify (?) your fuel there's a lot of possibilities including methanol which is a hell of a lot easier to deal with. The problem is that you need a source of carbon! So it works if you want to co generate with a fossil fuel or renewable crop power plant. It's an expensive pain if you're trying to pull it out of the atmosphere. Plants do it a whole lot cheaper than we can, they've had a lot of practice.

[J Tiers]

I'd rate ammonia as VERY problematic, as there is no chance to exclude nitrogen. So no good chance to increase efficiency by higher temperatures.

[wmgeorge]

Wow that is some incredible statistics
But at $1,200 for one battery ( takes four at 3.2V) it's a bit on the high side !


Rich

I pay $469 plus my state tax for my Renogy 12.8 volt 100 AH batteries. Renogy sells direct on eBay, prices for the exact same battery are all over the place so you need to shop carefully. You can discharge down to 80% without issues, rated for 2,000-5,000 cycles and 5 year warranty. Lead acid can only be discharged down to 50-80 % without long term damage.
The hydrogen store and fuel cell thing is got to be expensive, far more than the cost in battery storage.

[Lew Hartswick]

I heard a story from the guy who inspected my car the other day. He says he read that if you tow a Tesla with a Tesla it recharges the towed car faster than the tow car uses electricity. So in theory you can drive forever free by just switching positions. I guess you just have to buy two Tesla's.

I have two bridges, I wonder if that guy would be interested in, The Golden Gate and the Brooklyn. Some people are just born Stupid and nothing you can do will change that.
...lew...

[J Tiers]

I pay $469 plus my state tax for my Renogy 12.8 volt 100 AH batteries. Renogy sells direct on eBay, prices for the exact same battery are all over the place so you need to shop carefully. You can discharge down to 80% without issues, rated for 2,000-5,000 cycles and 5 year warranty. Lead acid can only be discharged down to 50-80 % without long term damage.
The hydrogen store and fuel cell thing is got to be expensive, far more than the cost in battery storage.

So, for those "advantages", you are paying $4.70 per amp-hour, vs 68 cents per a-h using T-105 batteries. And, to get the same ampere-hour capacity, you need to pay $1055 vs $157.

Even if we assume that the usable capacity (discharge depth) is double, AND the life is double, and discounting for that, you are still paying almost 4x the price of the T-105 for the same capacity. The weight is no advantage for a fixed PV system. For a system used as backup, the life advantages are no particular advantage either, as the batteries will be used in "float service" and a lead acid battery will last upwards of 15 years that way.

Cost vs hydrogen?

At 33kWh/kg for hydrogen, your batteries would cost $12,000 to store approximately the same energy as 1 kg of hydrogen. It would not surprise me if that 1kg could be stored for a fair bit less than $12,000.

For an actually usable system, storing 60 kWh, double that. (That IIRC is the storage capacity of some current EV's.)