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The main "why" is a carbon-free fuel (when produced by solar) in a relatively dense form. Liquid ammonia has higher energy density than liquid hydrogen, is easi

The main "why" is a carbon-free fuel (when produced by solar) in a relatively dense form. Liquid ammonia has higher energy density than liquid hydrogen, is easier to store, and is already used a bulk chemical around the world. It also is more energy efficient than liquifying hydrogen. If you imagined what oil would look like without carbon, ammonia is pretty close. The toxicity probably prevents cars and trucks from using ammonia, but for marine power or grid energy, it seems feasible. Also, the co-combustion fuel can be supplied on-site by cracking the ammonia to hydrogen. https://www.kallanishenergy.com/2020/07/08/air-products-to-build-5b-ammonia-project-in-saudi-arabia/ https://www.kallanishenergy.com/2020/07/08/air-products-to-b...

elcritch 6y ago
Cargo/freight shipping could be a prime target for a cleaner ammonia base fuel as most of the ships currently run dirty semi-processed petroleum, “bunker fuel”. It’s a hyper-cost sensitive market so without regulation I’d doubt ammonia would compete. Still it could be a feasible option to reduce pollution. Some Western countries might accept ammonia or similar diesel replacement, as it’d be a sort of natural tariff, but likely China would lobby hard against such a measure. There’s have to be a very strong push from a few nations, which I’ll doubt we’ll see anytime soon.
lpcam33 6y ago
What is the energy return of energy invested on getting hydrogen from solar and then turning into ammonia?
- adrianN 6y ago
  It's really poor, you need at least hydrogen for seasonal energy storage.
- ZeroGravitas 6y ago
  Are you counting the energy cost of preventing or mitigating climate change? It's not as good as plugging ibto the mains or using batteries, but it could well be the best option for industrial hydrogen, large boats and planes.
  - lpcam33 6y ago
    So we need to add into EROEI all the energy needed to deactivate/retrofit de old technology used in planes and large boats. If I don't do this exercise I will be as in denial as the ones that don't believe in climate change. We need to reduce air and maritime travel. We need to invest in trains and also avoid unnecessary travel. Fuel taxes in the previously mentioned sectors may be a good option because at the moment they don't have taxes on externalities. We have only a few years to prevent climate change getting out of hand and there are simple and effective solutions. We do not have a carbon budget for solutions that are not yet viable on paper.
dTal 6y ago
I'm confused. If we're stipulating carbon-neutral liquid fuel from renewable energy, what precisely is wrong with depolymerizing organic matter into ordinary hydrocarbons? Sure it generates CO2 at the point of use, but it's offset by the photosynthesis that made the organic matter. As long as the carbon cycle is a closed loop there shouldn't be problem, right?
- klodolph 6y ago
  I don't think the closed loop argument is sound. We care about the total amount of carbon in the loop, we care specifically about the amount in the atmosphere. That's the equilibrium point, and there's a lot you can do to push around the equilibrium point in a closed system.
  - dTal 6y ago
    Consider - we've been digging up ancient, sequestered carbon and putting it in the atmosphere on a mass industrial scale for hundreds of years. I don't think that anything we can do within the confines of a closed loop system is going to remotely compare with that. Or, to put it another way - we've been treating the atmosphere as a sink. But if we stop digging up carbon, we'll still need carbon, and it will become a source instead. By buffering that resource into fuel stocks and plastics and everything else we use carbon for, the only direction CO2 levels can go is down.
rbanffy 6y ago
> Liquid ammonia has higher energy density than liquid hydrogen Why not rockets then?
- chipsa 6y ago
  Methane is better than ammonia (less toxic, similar performance), while hydrogen is also still better (less toxic, higher performance), and hydrazine is also better (still toxic, but hypergolic with certain oxidizers). It has been used in rockets, but there's usually better choices.
  - rbanffy 6y ago
    I'd be suspicious of anything people would prefer hydrazine over. ;-)

elcritch 6y ago

Cargo/freight shipping could be a prime target for a cleaner ammonia base fuel as most of the ships currently run dirty semi-processed petroleum, “bunker fuel”. It’s a hyper-cost sensitive market so without regulation I’d doubt ammonia would compete. Still it could be a feasible option to reduce pollution. Some Western countries might accept ammonia or similar diesel replacement, as it’d be a sort of natural tariff, but likely China would lobby hard against such a measure. There’s have to be a very strong push from a few nations, which I’ll doubt we’ll see anytime soon.

lpcam33 6y ago

What is the energy return of energy invested on getting hydrogen from solar and then turning into ammonia?

adrianN 6y ago
It's really poor, you need at least hydrogen for seasonal energy storage.
ZeroGravitas 6y ago
Are you counting the energy cost of preventing or mitigating climate change? It's not as good as plugging ibto the mains or using batteries, but it could well be the best option for industrial hydrogen, large boats and planes.
- lpcam33 6y ago
  So we need to add into EROEI all the energy needed to deactivate/retrofit de old technology used in planes and large boats. If I don't do this exercise I will be as in denial as the ones that don't believe in climate change. We need to reduce air and maritime travel. We need to invest in trains and also avoid unnecessary travel. Fuel taxes in the previously mentioned sectors may be a good option because at the moment they don't have taxes on externalities. We have only a few years to prevent climate change getting out of hand and there are simple and effective solutions. We do not have a carbon budget for solutions that are not yet viable on paper.

dTal 6y ago

I'm confused. If we're stipulating carbon-neutral liquid fuel from renewable energy, what precisely is wrong with depolymerizing organic matter into ordinary hydrocarbons? Sure it generates CO2 at the point of use, but it's offset by the photosynthesis that made the organic matter. As long as the carbon cycle is a closed loop there shouldn't be problem, right?

klodolph 6y ago
I don't think the closed loop argument is sound. We care about the total amount of carbon in the loop, we care specifically about the amount in the atmosphere. That's the equilibrium point, and there's a lot you can do to push around the equilibrium point in a closed system.
- dTal 6y ago
  Consider - we've been digging up ancient, sequestered carbon and putting it in the atmosphere on a mass industrial scale for hundreds of years. I don't think that anything we can do within the confines of a closed loop system is going to remotely compare with that. Or, to put it another way - we've been treating the atmosphere as a sink. But if we stop digging up carbon, we'll still need carbon, and it will become a source instead. By buffering that resource into fuel stocks and plastics and everything else we use carbon for, the only direction CO2 levels can go is down.

rbanffy 6y ago

> Liquid ammonia has higher energy density than liquid hydrogen Why not rockets then?

chipsa 6y ago
Methane is better than ammonia (less toxic, similar performance), while hydrogen is also still better (less toxic, higher performance), and hydrazine is also better (still toxic, but hypergolic with certain oxidizers). It has been used in rockets, but there's usually better choices.
- rbanffy 6y ago
  I'd be suspicious of anything people would prefer hydrazine over. ;-)