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Soooo... It has to be mixed with a co-combustion fuel, is dirtier than diesel, and requires more space and weight to clean up it's exhaust. The article really

Soooo... It has to be mixed with a co-combustion fuel, is dirtier than diesel, and requires more space and weight to clean up it's exhaust. The article really should have gone into some of the 'why' side of things - what are the advantages of ammonia?

piannucci 6y ago
Knowing nothing about this, broadly speaking, the enthalpy of formation of the diatomic nitrogen molecule is very high, and you might expect to achieve high energy density. Also it does not produce any CO2.
- neltnerb 6y ago
  So for context -- I was working on this ten years ago. I don't have much to say about this particular example other than to note that almost all ammonia today is made using natural gas as the hydrogen source. Using ammonia is a neat idea, if made renewably, but it will continue to be a challenge to use in cars because it is pressurized, corrosive, and toxic even compared to gasoline. Obviously the bigger market for renewable ammonia should be fertilizers because right now we're feeding our crops petrochemicals in order to get high enough yields to feed us. That seems like a bad situation to put yourself in if there's any other choice.
  - AprilArcus 6y ago
    It's technologically trivial to make renewable hydrogen from clean electricity and non-potable water, under the right economic incentives (Carbon tax)
    - neltnerb 6y ago
      Indeed. I would put "making transportation fuels" at about the bottom of the list in terms of the best use of electricity until such time as all electricity is renewable. It just doesn't make sense until the entire grid or close to it is renewable already because if you use 1J of electricity to make 0.95J of hydrogen that gets turned into 0.9J of ammonia you'd have been way better off just using 0.9J of gasoline in the first place because that 1J of electricity probably was generated from 3J of fossil fuels. So I'd say the same regarding fertilizers -- I'd rather they didn't use natural gas as a hydrogen feedstock, but generating hydrogen from electricity generated at a natural gas plant is a very Rube Goldbergy way to generate ammonia that still uses natural gas. That's changing, but it's nowhere near true yet. Generating ammonia from excess renewable electricity that the grid can't sink does make more sense to me.
      - Symmetry 6y ago
        I'm not sure I'd agree about ordering. Solar power seems to be getting cheaper faster than batteries are. We might be in the position in the not too distant future where we have more electricity during sunny days than we know what to do with but still need some natural gas power plants to get us through cloudy months. Depending on capital costs "make H while the sun shines" might be a reasonable business.
        neltnerb 6y ago
        Yeah, I am also on board with diverting excess electricity into transportation fuels if it literally can't fit on the grid. But every joule of electricity generated from renewables that makes it to the grid is a joule of electricity that wasn't generated with petrochemicals at the moment because natural gas peaker plants are still a thing. I had to once write a grant proposal for essentially the kind of thing you're talking about. It's exceptionally hard to make a good overall systems efficiency case for taking electricity and turning it back into fuels. I hope you agree that displacement of petrochemical electricity sources is far preferable to generating chemicals as a byproduct if the grid does have room for more electrons. The only way I was able to find to make it work economically was to take excess electricity and convert it into fairly high value chemicals -- but even there, just turning petrochemicals into those same chemicals would in almost every case be more efficient. I look forward to the day when we have so much renewable generation that we have no petrochemical electric plants left to displace. Hopefully it is not too far off, I like your optimism about solar and agree it may be warranted.
        chipsa 6y ago
        The spot price of electricity has gone negative in certain times and places. So power from then could potentially have not have been generated from petrochemicals (though, it might have been from a oil or coal fired steam plant). If we could change the natural gas peaker plants to ammonia powered peaker plants, we could also use plants that are more base-load(nuclear), and use the ammonia as a long term power storage.
    - hechang1997 6y ago
      You can also make it with natural gas and capture the CO2 produced.
jccooper 6y ago
If they had a FAQ I'd be looking for "How does ammonia power handle the many significant dangers of ammonia?" Except when extremely diluted that stuff makes diesel look like milk.
FranOntanaya 6y ago
Maybe it'd work for large trucks in very cold environments. Not much around in an accident and it handles lower temperatures.
asdfadsfgfdda 6y ago
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.
jessaustin 6y ago
It has to be mixed with diesel in order to function in compression ignition engines, otherwise known as "diesel engines". So, this "criticism" could be leveled at gasoline and other fuels as well. Spark plugs will ignite ammonia just fine. There is a single reference to this in a different post on the site. [0] My understanding is that most "hobbyist" ammonia fuel setups (i.e. "my pickup runs on ammonia now!") also use spark ignition. I suspect they're investigating the diesel engine possibilities because they would require fewer modifications to existing large marine engines. [0] https://www.ammoniaenergy.org/articles/wartsila-tests-internal-combustion-of-ammonia/ https://www.ammoniaenergy.org/articles/wartsila-tests-intern...

piannucci 6y ago

Knowing nothing about this, broadly speaking, the enthalpy of formation of the diatomic nitrogen molecule is very high, and you might expect to achieve high energy density. Also it does not produce any CO2.

neltnerb 6y ago
So for context -- I was working on this ten years ago. I don't have much to say about this particular example other than to note that almost all ammonia today is made using natural gas as the hydrogen source. Using ammonia is a neat idea, if made renewably, but it will continue to be a challenge to use in cars because it is pressurized, corrosive, and toxic even compared to gasoline. Obviously the bigger market for renewable ammonia should be fertilizers because right now we're feeding our crops petrochemicals in order to get high enough yields to feed us. That seems like a bad situation to put yourself in if there's any other choice.
- AprilArcus 6y ago
  It's technologically trivial to make renewable hydrogen from clean electricity and non-potable water, under the right economic incentives (Carbon tax)
  - neltnerb 6y ago
    Indeed. I would put "making transportation fuels" at about the bottom of the list in terms of the best use of electricity until such time as all electricity is renewable. It just doesn't make sense until the entire grid or close to it is renewable already because if you use 1J of electricity to make 0.95J of hydrogen that gets turned into 0.9J of ammonia you'd have been way better off just using 0.9J of gasoline in the first place because that 1J of electricity probably was generated from 3J of fossil fuels. So I'd say the same regarding fertilizers -- I'd rather they didn't use natural gas as a hydrogen feedstock, but generating hydrogen from electricity generated at a natural gas plant is a very Rube Goldbergy way to generate ammonia that still uses natural gas. That's changing, but it's nowhere near true yet. Generating ammonia from excess renewable electricity that the grid can't sink does make more sense to me.
    - Symmetry 6y ago
      I'm not sure I'd agree about ordering. Solar power seems to be getting cheaper faster than batteries are. We might be in the position in the not too distant future where we have more electricity during sunny days than we know what to do with but still need some natural gas power plants to get us through cloudy months. Depending on capital costs "make H while the sun shines" might be a reasonable business.
      - neltnerb 6y ago
        Yeah, I am also on board with diverting excess electricity into transportation fuels if it literally can't fit on the grid. But every joule of electricity generated from renewables that makes it to the grid is a joule of electricity that wasn't generated with petrochemicals at the moment because natural gas peaker plants are still a thing. I had to once write a grant proposal for essentially the kind of thing you're talking about. It's exceptionally hard to make a good overall systems efficiency case for taking electricity and turning it back into fuels. I hope you agree that displacement of petrochemical electricity sources is far preferable to generating chemicals as a byproduct if the grid does have room for more electrons. The only way I was able to find to make it work economically was to take excess electricity and convert it into fairly high value chemicals -- but even there, just turning petrochemicals into those same chemicals would in almost every case be more efficient. I look forward to the day when we have so much renewable generation that we have no petrochemical electric plants left to displace. Hopefully it is not too far off, I like your optimism about solar and agree it may be warranted.
        chipsa 6y ago
        The spot price of electricity has gone negative in certain times and places. So power from then could potentially have not have been generated from petrochemicals (though, it might have been from a oil or coal fired steam plant). If we could change the natural gas peaker plants to ammonia powered peaker plants, we could also use plants that are more base-load(nuclear), and use the ammonia as a long term power storage.
  - hechang1997 6y ago
    You can also make it with natural gas and capture the CO2 produced.

jccooper 6y ago

If they had a FAQ I'd be looking for "How does ammonia power handle the many significant dangers of ammonia?" Except when extremely diluted that stuff makes diesel look like milk.

FranOntanaya 6y ago

Maybe it'd work for large trucks in very cold environments. Not much around in an accident and it handles lower temperatures.

asdfadsfgfdda 6y ago

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.

jessaustin 6y ago

It has to be mixed with diesel in order to function in compression ignition engines, otherwise known as "diesel engines". So, this "criticism" could be leveled at gasoline and other fuels as well. Spark plugs will ignite ammonia just fine. There is a single reference to this in a different post on the site. [0] My understanding is that most "hobbyist" ammonia fuel setups (i.e. "my pickup runs on ammonia now!") also use spark ignition. I suspect they're investigating the diesel engine possibilities because they would require fewer modifications to existing large marine engines. [0] https://www.ammoniaenergy.org/articles/wartsila-tests-internal-combustion-of-ammonia/ https://www.ammoniaenergy.org/articles/wartsila-tests-intern...