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From a CO2 emissions reduction perspective, it seems far better to use green ammonia as a direct replacement for fossil-derived ammonia used in fertilizers.

by danans 4y ago

legulere 4y ago
Certainly, however Europe won’t be able to fulfill all of its energy needs by local production. Hydrogen is too difficult to ship, so probably ammonia will get shipped instead. Also you have the issue of ships that can’t get electrified yet. Green ammonia might be one way to replace fossil fuels.
- pencilguin 4y ago
  There are already definite plans in play to transition shipping to green ammonia.
- danans 4y ago
  > Europe won’t be able to fulfill all of its energy needs by local production In the long run, why not? Between overbuilding renewable capacity (needed for green ammonia anyway), using nuclear when it's cost effective and renewable energy is limited, and multi-day storage, Europe should get pretty close. The last couple percent can be bridged with fossil fuels.
- tpm 4y ago
  Natural gas pipelines can be upgraded to transport hydrogen instead.
  - jillesvangurp 4y ago
    Not that easy. Hydrogen is very hard to contain. Given gas leaks and gas explosions are already a regular thing, pushing hydrogen through the same leaky pipes is not going to improve things. There's this hydrogen fantasy where people think it's a drop in replacement for methane. The reality is that most hydrogen that is currently produced (from vast amounts of methane typically), is used on site. Transporting it around is just very hard. Even in compressed form, it still takes up a lot of space. Diesel has much better energy density by volume than hydrogen compressed at 300 bar. About 18x for the same volume.
    - tpm 4y ago
      I know, this information is coming from a private conversation with an expert who has done an analysis on this and says it's actually both plausible and much cheaper to do than shipping hydrogen.
- janef0421 4y ago
  I think using an integrated nuclear reactor would be a better solution than using ammonia fuel. Better energy efficiency, increased speeds, reduced fuel handling costs, and greater operational flexibility are clear advantages. I would also argue the environmental risks are reduced.
  - Schroedingersat 4y ago
    So designing a ship from scratch with a reactor that doesn't exist that would cost at minimum well over double what existing entire ships cost which uses high enriched fuel that almost as much in raw natural Uranium as existing (filthy) bunker fuel and then sending that high enriched Uranium (which will have a high percentage of chemically separable plutonium unless you refuel yearly at enormous expense and downtime) all over the world, without security or oversight, managed by an industry that cuts costs and breaks laws constantly is a better plan than... Changing some emissions control equipment, enlarging the fuel tank a little and giving them ammonia when they dock?
    - janef0421 4y ago
      I am confused. Why do you think a nuclear cargo ship would use highly enriched uranium?
      - Schroedingersat 4y ago
        Low enrichment, compact, long fuel cycle. Choose two.
jillesvangurp 4y ago
Exactly. Ammonia gets produced from (mostly) grey hydrogen. And the most common application for ammonia is producing fertilizers. Making that process green, would cut down on a lot of carbon emissions (several percent of global emissions) and should be the first priority before considering inefficient ways to use hydrogen and ammonia like this. Ammonia as a fuel is quite inefficient due to all the energy conversions. You use renewable electricity to generate hydrogen. You use that to create ammonia. And you then burn that to produce mechanical energy. Each of those steps has poor efficiencies and they multiply. It is way less efficient than using renewable energy to charge a battery that powers an electrical motor. If you start with 10kwh of renewable electricity, you'd be struggling to get more than 1-2kwh delivered in the form of mechanical energy with ammonia. With battery electric it's more like 8kwh. Charging and discharging the battery loses some energy and electrical motors are of course also not 100% efficient. And when I say inefficient, I mean costly. You waste most of the energy that you put in. It's much more cost effective to use the energy in a more efficient way. By about a factor of 4-5. If you operate any business where energy cost is significant the value proposition of paying 4-5x more is not great. It's why ammonia as a fuel really barely makes any sense. And hydrogen as a fuel is pretty bad for the same reason. It's a really hard sell when battery electric is a feasible alternative. The economics are flawed. And the second law of thermodynamics means there is no technical fix for this either. There are some hard theoretical limits here.
- tuatoru 4y ago
  Efficiency is very important when your energy is costly. But other attributes like reliability, safety, environmental benignity, "fit" in the overall energy system, and aesthetics start to take precedence over energy efficiency at some point. The way things are trending with PV, efficiency may recede in importance in a couple of decades. Currently electricity costs tens of dollars per MWh. With developments in manufacturing and install protocols, and tech emerging from the lab, and using DC directly from PV panels, that cost may fall to $0.1 per MWh. Using that to manufacture your ammonia means you won't worry so much about pure efficiency I still prefer methane over ammonia. Much less toxic when things go wrong.
  - 4y ago

From a CO2 emissions reduction perspective, it seems far better to use green ammonia as a direct replacement for fossil-derived ammonia used in fertilizers.

by danans 4y ago

From a CO2 emissions reduction perspective, it seems far better to use green ammonia as a direct replacement for fossil-derived ammonia used in fertilizers.

legulere 4y ago

Certainly, however Europe won’t be able to fulfill all of its energy needs by local production. Hydrogen is too difficult to ship, so probably ammonia will get shipped instead. Also you have the issue of ships that can’t get electrified yet. Green ammonia might be one way to replace fossil fuels.

pencilguin 4y ago
There are already definite plans in play to transition shipping to green ammonia.
danans 4y ago
> Europe won’t be able to fulfill all of its energy needs by local production In the long run, why not? Between overbuilding renewable capacity (needed for green ammonia anyway), using nuclear when it's cost effective and renewable energy is limited, and multi-day storage, Europe should get pretty close. The last couple percent can be bridged with fossil fuels.
tpm 4y ago
Natural gas pipelines can be upgraded to transport hydrogen instead.
- jillesvangurp 4y ago
  Not that easy. Hydrogen is very hard to contain. Given gas leaks and gas explosions are already a regular thing, pushing hydrogen through the same leaky pipes is not going to improve things. There's this hydrogen fantasy where people think it's a drop in replacement for methane. The reality is that most hydrogen that is currently produced (from vast amounts of methane typically), is used on site. Transporting it around is just very hard. Even in compressed form, it still takes up a lot of space. Diesel has much better energy density by volume than hydrogen compressed at 300 bar. About 18x for the same volume.
  - tpm 4y ago
    I know, this information is coming from a private conversation with an expert who has done an analysis on this and says it's actually both plausible and much cheaper to do than shipping hydrogen.
janef0421 4y ago
I think using an integrated nuclear reactor would be a better solution than using ammonia fuel. Better energy efficiency, increased speeds, reduced fuel handling costs, and greater operational flexibility are clear advantages. I would also argue the environmental risks are reduced.
- Schroedingersat 4y ago
  So designing a ship from scratch with a reactor that doesn't exist that would cost at minimum well over double what existing entire ships cost which uses high enriched fuel that almost as much in raw natural Uranium as existing (filthy) bunker fuel and then sending that high enriched Uranium (which will have a high percentage of chemically separable plutonium unless you refuel yearly at enormous expense and downtime) all over the world, without security or oversight, managed by an industry that cuts costs and breaks laws constantly is a better plan than... Changing some emissions control equipment, enlarging the fuel tank a little and giving them ammonia when they dock?
  - janef0421 4y ago
    I am confused. Why do you think a nuclear cargo ship would use highly enriched uranium?
    - Schroedingersat 4y ago
      Low enrichment, compact, long fuel cycle. Choose two.

jillesvangurp 4y ago

Exactly. Ammonia gets produced from (mostly) grey hydrogen. And the most common application for ammonia is producing fertilizers. Making that process green, would cut down on a lot of carbon emissions (several percent of global emissions) and should be the first priority before considering inefficient ways to use hydrogen and ammonia like this. Ammonia as a fuel is quite inefficient due to all the energy conversions. You use renewable electricity to generate hydrogen. You use that to create ammonia. And you then burn that to produce mechanical energy. Each of those steps has poor efficiencies and they multiply. It is way less efficient than using renewable energy to charge a battery that powers an electrical motor. If you start with 10kwh of renewable electricity, you'd be struggling to get more than 1-2kwh delivered in the form of mechanical energy with ammonia. With battery electric it's more like 8kwh. Charging and discharging the battery loses some energy and electrical motors are of course also not 100% efficient. And when I say inefficient, I mean costly. You waste most of the energy that you put in. It's much more cost effective to use the energy in a more efficient way. By about a factor of 4-5. If you operate any business where energy cost is significant the value proposition of paying 4-5x more is not great. It's why ammonia as a fuel really barely makes any sense. And hydrogen as a fuel is pretty bad for the same reason. It's a really hard sell when battery electric is a feasible alternative. The economics are flawed. And the second law of thermodynamics means there is no technical fix for this either. There are some hard theoretical limits here.

tuatoru 4y ago
Efficiency is very important when your energy is costly. But other attributes like reliability, safety, environmental benignity, "fit" in the overall energy system, and aesthetics start to take precedence over energy efficiency at some point. The way things are trending with PV, efficiency may recede in importance in a couple of decades. Currently electricity costs tens of dollars per MWh. With developments in manufacturing and install protocols, and tech emerging from the lab, and using DC directly from PV panels, that cost may fall to $0.1 per MWh. Using that to manufacture your ammonia means you won't worry so much about pure efficiency I still prefer methane over ammonia. Much less toxic when things go wrong.
- 4y ago