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2026 is still a very ambitious startup date for this. The International Maritime Organisation (IMO) has only just approved interim guidelines for the addition

2026 is still a very ambitious startup date for this. The International Maritime Organisation (IMO) has only just approved interim guidelines for the addition of ammonia to the IGF Code (use of gaseous fuels). There's a lot to it, but this is a good high level overview: https://www.linkedin.com/pulse/imo-interim-guidelines-safety-ships-using-ammonia-fuel-muammer-akturk-n2e0c/ https://www.linkedin.com/pulse/imo-interim-guidelines-safety... A lot of commentators believe that since ammonia is less inherently safe it will inevitably be less safe in practice. I am not convinced by that argument, and in general if there's a strong enough business driver then anything can be made safe. But what really swung me against the idea of ammonia as a shipping fuel is that the expected cost is barely any better than methanol (which is much more inherently safe) and is more expensive than biodiesel. The shipping companies have a real conundrum on their hands - do they go ammonia, methanol, stick with diesel, or try to get near-shore and inland shipping onto electric? Ammonia-fuelled ships have to be THOROUGHLY designed from the ground up specifically for ammonia use; you have to be 100% committed to go down that path. Whereas biodiesel can simply be dropped in (you can of course choose to fill up with a biodiesel blend today, but nobody does because you can put emissions into the atmosphere for free). Unlike solar cells or battery cells, I don't really see much chance for 'learning rates' and technology improvement to drastically drive down the cost of green ammonia. Falling electrolyser costs are nice, but they're only a portion of the process plant CAPEX, and the cost of the green electricity dominates the economics over the process plant CAPEX anyway. You could get electrolysers for free and still be unable to make cheap green ammonia. So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive.

rbanffy 2y ago
> So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. And next to ammonia, biodiesel is almost drinkable.
- marcosdumay 2y ago
  And there's the entire CO versus NO or NO2. But well, the silver lining is that the combustion products literally burning your lungs means that you won't unknowingly lock yourself in a room with a running engine.
  - rbanffy 2y ago
    Also a very unlikely form of suicide - people generally opt for less painful ways to die.
rzwitserloot 2y ago
I'm pretty sure the costs of producing a fuel based solely on making it with electricity is by far, of all the options you named, best done with Ammonia. The reason the cost of ammonia is barely better, or even worse, than things like methanol, is because the electricity process is still expensive. But that can (and soon would!) become waaaay cheaper. Electricity __NOT__ on demand is dirt cheap and can be halved and quartered some more: Solar panels are _idiotically cheap_ these days and that state of affairs is not temporary. We need more not-on-demand needs. As in, 'hey, uh, if theres some power left over cuz it's windy and sunny.. no prob! Let me run these ammonia producing machines at full power for a bit. No need for ammonia right now? No problem - compared to electricity, ammonia is vastly simpler to store'. Ammonia is a great not-on-demand consumer of electricty. That's why this is necessary. As you said: > the cost of the green electricity dominates the economics over the process plant CAPEX anyway. That's exactly the factor that can become ridiculously cheap. It isn't today because there's not much point investing in solar/wind because they do not cover on-demand needs (when it's not particularly sunny/windy, then electricity prices are sky high and you want to build electricity production that can deliver then. And solar/windy by definition can't), and the primary issue is transport. if the demand for ammonia skyrockets, you can solve it all. Ammonia does not need to be produced on-demand, and you don't need all that much transport (build the ammonia producing plant close to your solar/wind parks).
- pjc50 2y ago
  > Let me run these ammonia producing machines at full power for a bit. The problem with this is the capex and running costs of that kind of machinery make it expensive to keep idle. It can be uneconomic even with free electricity.
  - bluGill 2y ago
    Where are the costs. Many factories are only used 8 hours a day despite the high costs - it isn't worth the additional cost to have employees work overnight. Some really energy hungry factories traditionally run only overnight when energy is cheap, and they shutdown for yearly maintenance in December (thus freeing up their normal energy use when everyone is running Christmas lights) Now that wind and solar are coming online those are changing how they work. Different factories have difference costs. When energy is significant they consider that. When energy is not significant they just run when it works out.
pjc50 2y ago
Short distance electric shipping seems the most feasible. Scotland is making steps in this direction. https://www.offshore-energy.biz/scotland-to-buy-seven-electric-ferries/ https://www.offshore-energy.biz/scotland-to-buy-seven-electr... Long distance .. this is just a problem. As you say it won't be solved unless there's carbon pricing and ultimately restrictions on fossil fuels in general, forcing a replacement with more expensive synthetic and bio-fuels.
- jillesvangurp 2y ago
  I think long distance might be solvable too with a little out of the box thinking. Imagine ships could swap out batteries every few hundred miles. Think simple container batteries and some off shore wind park with facilities for charging container batteries and a stash of charged batteries. Floating off shore wind is now possible as well. Containers might be a bit tedious for this. So, why not use autonomous tug boats and barges. The tug boats simply pull the load between charging stations. When they are empty they head for a charger and a full one takes over. This could even work with existing ships, which are commonly maneuvered around harbors using tug boats already. Probably more than a few engineering challenges lurking here but it gets us out of the mindset that ships must be able to go for thousands of nautical miles without stopping for charging. I could see that working for a lot of coastal shipping routes.
  - pjc50 2y ago
    Container batteries already seem to be a thing: https://www.offshore-energy.biz/worlds-first-700-teu-pure-battery-powered-containerships-are-here/ https://www.offshore-energy.biz/worlds-first-700-teu-pure-ba... .. but again for relatively short distances. You do not want to have relatively unskilled personnel attempting swaps at sea, or in bad weather (which is also very dangerous for ships under tow). The China-EU distance is about 24,000km. I don't think more than one or two charging/swap stops are feasible on that route, so you're going to need something with 10,000km range at the very least.
    - bluGill 2y ago
jillesvangurp 2y ago
Cost is indeed the core issue. It's an issue with most synthetic fuels and it's not an issue that is likely to go away. As long as that means you have to pay a steep premium to be green, it's not going to be popular. International agreement on carbon taxes is unlikely. And most ships operate in international waters under the flags of countries with favorable taxes and rules (e.g. Panama, Greece, etc.). With shipping, shooting for perfect is really expensive. But we're starting with a status quo that is really bad that can be improved upon. For example, most ships are made out of steel. Steel is relatively heavy. There's a ship yard in Tasmania working on a battery electric 300meter long ferry made out of aluminum. They've built dozens of aluminum ships already. Aluminum is much lighter than steel and that cuts the amount of energy needed to move it around by about half. That's nice because batteries are expensive and don't provide a lot of range. But making ferries out of aluminum is of course something that could work for any kind of ship. Fuel is really expensive. 50% fuel savings are very attractive to ship operators. Most ships burn bunker fuel. That's properly nasty stuff. So using only half of that would be an improvement. It's toxic, causes lots of pollution and is nasty if it gets in the water. Some cruise ships run on LNG these days. Much cleaner but it takes up space. Those ships are mostly still made out of steel. If you make them out of aluminum, they'd be a lot lighter probably and use less fuel. So smaller LNG tanks, less CO2 emitted, and more space for the passengers. Win win. There are also some interesting things happening with composites and carbon fiber. That stuff is even lighter and there are some companies focusing on marine applications as well. So, we could cut weight and fuel usage of ships by using modern/different materials. There are some experiments happening with using sails on ships to cut fuel usage further. If you add all this up, we could be cutting fuel usage significantly (40-70%) and make the emissions problem a lot smaller. And unlike synthetic fuels, this also translates into financial savings. So that means it's more likely to happen. And if we eventually put batteries in these ships, they'll go a bit further as well. It's not perfect. But probably a lot better.
- pjc50 2y ago
  > Aluminum is much lighter than steel and that cuts the amount of energy needed to move it around by about half. Hmm. I'm suspicious about this - might be true for cars, definitely true for planes, but ships sit at neutral buoyancy, most of the mass is cargo, and the main component of energy expenditure is actually drag. So there's significant benefits to low drag hull designs or "slow steaming", but the actual ship material isn't terribly high up on the priority list. And aluminium is way more expensive.
scythe 2y ago
>Unlike solar cells or battery cells, I don't really see much chance for 'learning rates' and technology improvement to drastically drive down the cost of green ammonia. Falling electrolyser costs are nice, but they're only a portion of the process plant CAPEX, and the cost of the green electricity dominates the economics over the process plant CAPEX anyway. You could get electrolysers for free and still be unable to make cheap green ammonia. So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. There is a ton of research going into improving the efficiency of the H2 > NH3 conversion, and there are at least two startups (Tsubame in Japan and a new one I don't remember). There's no rule that says you can't beat Haber. Compared to methanol, ammonia is currently more expensive but vastly more scalable in the long run; once you reach the biofuel "ceiling" (roughly corresponding to the availability of farming and forestry byproducts) you're stuck making it via carbon capture, which has its own efficiency problems.
- kragen 2y ago
  By "efficiency" do you mean energy consumption or hydrogen consumption?
  - scythe 2y ago
    Energy consumption. I am pretty sure that the hydrogen utilization in most ammonia production is very high. In theory the energy required to produce ammonia is negative (Hf < 0) but at standard pressure its formation is thermodynamically unfavorable (Gf = Hf + TdeltaS > 0). But the bigger issue is the very high activation energy barrier for ammonia synthesis, which results in a lot of energy being used to make ammonia at very high pressure and temperature. Right now there are two competing approaches to reducing the cost of ammonia production. Tsubame is using a new ruthenium-based catalyst that lowers the reaction temperature (and therefore, also the pressure). The other method is by electrocatalysis. I don't know for sure that this is what NitroVolt is doing but their name certainly suggests it.
    - kragen 2y ago
Anduia 2y ago
That linkedin post seems AI generated, got a better source?
jgraham 2y ago
Note that biofuels aren't especially environmentally friendly, even just considering carbon emissions. See e.g. [1], which makes the most optimistic possible assumption by ignoring land use changes and still concludes "the reductions for most feedstocks are insufficient to meet the GHG savings required by the EU Renewable Energy Directive" (second generation biofuels may do better, but that isn't clear). Also ignoring land use changes is a very bad asssumption; if your plan is to run global shipping (or other industries) on biofuels it seems highly implausible that it's not going to end up with more land overall used for growing crops. If that's land that could otherwise be sequestering carbon (e.g. drained peat bogs, which have the advantage of being highly fertile), then it's clearly going to be a significant contribution to carbon emissions (not to mention the ecological impacts of converting yet more land to agriculture). [1] https://royalsocietypublishing.org/doi/10.1098/rspa.2020.0351 https://royalsocietypublishing.org/doi/10.1098/rspa.2020.035...
kragen 2y ago
> Unlike solar cells or battery cells, I don't really see much chance for 'learning rates' and technology improvement to drastically drive down the cost of green ammonia. Falling electrolyser costs are nice, but they're only a portion of the process plant CAPEX, and the cost of the green electricity dominates the economics over the process plant CAPEX anyway. (...) So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. You seem to be contradicting yourself here? If learning rates and technology improvement drastically drive down the cost of solar cells, as you say they might, and the cost of electricity dominates the cost of green ammonia, as you say it does, doesn't that mean that the learning rates and technology improvement in solar cells will drastically drive down the cost of green ammonia? Wouldn't that make ammonia much cheaper than biodiesel, keeping biodiesel from being competitive? (I'm not sure ammonia is a competitive fuel for other reasons, such as the corrosion and safety issues discussed in the article, but it seems clear to me that if it's going to be uncompetitively expensive, it would have to be because one of the premises above is wrong, for example because the cost of green ammonia is dominated by capex or because solar cells stop dropping in cost. I don't see how you can sustain those premises and deny the conclusion.)
whatever1 2y ago
At this risk envelope I don’t see why nuclear / battery hybrids are not a serious contender. We can for example have them work on purely electric mode when close to ports and then enable the reactor in the open sea. We do something similar with bunker fuel of different grades. They are forced to use the good stuff near the ports and once in the open sea they start burning the muddy Godzilla.

rbanffy 2y ago

> So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. And next to ammonia, biodiesel is almost drinkable.

marcosdumay 2y ago
And there's the entire CO versus NO or NO2. But well, the silver lining is that the combustion products literally burning your lungs means that you won't unknowingly lock yourself in a room with a running engine.
- rbanffy 2y ago
  Also a very unlikely form of suicide - people generally opt for less painful ways to die.

rzwitserloot 2y ago

I'm pretty sure the costs of producing a fuel based solely on making it with electricity is by far, of all the options you named, best done with Ammonia. The reason the cost of ammonia is barely better, or even worse, than things like methanol, is because the electricity process is still expensive. But that can (and soon would!) become waaaay cheaper. Electricity __NOT__ on demand is dirt cheap and can be halved and quartered some more: Solar panels are _idiotically cheap_ these days and that state of affairs is not temporary. We need more not-on-demand needs. As in, 'hey, uh, if theres some power left over cuz it's windy and sunny.. no prob! Let me run these ammonia producing machines at full power for a bit. No need for ammonia right now? No problem - compared to electricity, ammonia is vastly simpler to store'. Ammonia is a great not-on-demand consumer of electricty. That's why this is necessary. As you said: > the cost of the green electricity dominates the economics over the process plant CAPEX anyway. That's exactly the factor that can become ridiculously cheap. It isn't today because there's not much point investing in solar/wind because they do not cover on-demand needs (when it's not particularly sunny/windy, then electricity prices are sky high and you want to build electricity production that can deliver then. And solar/windy by definition can't), and the primary issue is transport. if the demand for ammonia skyrockets, you can solve it all. Ammonia does not need to be produced on-demand, and you don't need all that much transport (build the ammonia producing plant close to your solar/wind parks).

pjc50 2y ago
> Let me run these ammonia producing machines at full power for a bit. The problem with this is the capex and running costs of that kind of machinery make it expensive to keep idle. It can be uneconomic even with free electricity.
- bluGill 2y ago
  Where are the costs. Many factories are only used 8 hours a day despite the high costs - it isn't worth the additional cost to have employees work overnight. Some really energy hungry factories traditionally run only overnight when energy is cheap, and they shutdown for yearly maintenance in December (thus freeing up their normal energy use when everyone is running Christmas lights) Now that wind and solar are coming online those are changing how they work. Different factories have difference costs. When energy is significant they consider that. When energy is not significant they just run when it works out.

pjc50 2y ago

Short distance electric shipping seems the most feasible. Scotland is making steps in this direction. https://www.offshore-energy.biz/scotland-to-buy-seven-electric-ferries/ https://www.offshore-energy.biz/scotland-to-buy-seven-electr... Long distance .. this is just a problem. As you say it won't be solved unless there's carbon pricing and ultimately restrictions on fossil fuels in general, forcing a replacement with more expensive synthetic and bio-fuels.

jillesvangurp 2y ago
I think long distance might be solvable too with a little out of the box thinking. Imagine ships could swap out batteries every few hundred miles. Think simple container batteries and some off shore wind park with facilities for charging container batteries and a stash of charged batteries. Floating off shore wind is now possible as well. Containers might be a bit tedious for this. So, why not use autonomous tug boats and barges. The tug boats simply pull the load between charging stations. When they are empty they head for a charger and a full one takes over. This could even work with existing ships, which are commonly maneuvered around harbors using tug boats already. Probably more than a few engineering challenges lurking here but it gets us out of the mindset that ships must be able to go for thousands of nautical miles without stopping for charging. I could see that working for a lot of coastal shipping routes.
- pjc50 2y ago
  Container batteries already seem to be a thing: https://www.offshore-energy.biz/worlds-first-700-teu-pure-battery-powered-containerships-are-here/ https://www.offshore-energy.biz/worlds-first-700-teu-pure-ba... .. but again for relatively short distances. You do not want to have relatively unskilled personnel attempting swaps at sea, or in bad weather (which is also very dangerous for ships under tow). The China-EU distance is about 24,000km. I don't think more than one or two charging/swap stops are feasible on that route, so you're going to need something with 10,000km range at the very least.
  - bluGill 2y ago

jillesvangurp 2y ago

Cost is indeed the core issue. It's an issue with most synthetic fuels and it's not an issue that is likely to go away. As long as that means you have to pay a steep premium to be green, it's not going to be popular. International agreement on carbon taxes is unlikely. And most ships operate in international waters under the flags of countries with favorable taxes and rules (e.g. Panama, Greece, etc.). With shipping, shooting for perfect is really expensive. But we're starting with a status quo that is really bad that can be improved upon. For example, most ships are made out of steel. Steel is relatively heavy. There's a ship yard in Tasmania working on a battery electric 300meter long ferry made out of aluminum. They've built dozens of aluminum ships already. Aluminum is much lighter than steel and that cuts the amount of energy needed to move it around by about half. That's nice because batteries are expensive and don't provide a lot of range. But making ferries out of aluminum is of course something that could work for any kind of ship. Fuel is really expensive. 50% fuel savings are very attractive to ship operators. Most ships burn bunker fuel. That's properly nasty stuff. So using only half of that would be an improvement. It's toxic, causes lots of pollution and is nasty if it gets in the water. Some cruise ships run on LNG these days. Much cleaner but it takes up space. Those ships are mostly still made out of steel. If you make them out of aluminum, they'd be a lot lighter probably and use less fuel. So smaller LNG tanks, less CO2 emitted, and more space for the passengers. Win win. There are also some interesting things happening with composites and carbon fiber. That stuff is even lighter and there are some companies focusing on marine applications as well. So, we could cut weight and fuel usage of ships by using modern/different materials. There are some experiments happening with using sails on ships to cut fuel usage further. If you add all this up, we could be cutting fuel usage significantly (40-70%) and make the emissions problem a lot smaller. And unlike synthetic fuels, this also translates into financial savings. So that means it's more likely to happen. And if we eventually put batteries in these ships, they'll go a bit further as well. It's not perfect. But probably a lot better.

pjc50 2y ago
> Aluminum is much lighter than steel and that cuts the amount of energy needed to move it around by about half. Hmm. I'm suspicious about this - might be true for cars, definitely true for planes, but ships sit at neutral buoyancy, most of the mass is cargo, and the main component of energy expenditure is actually drag. So there's significant benefits to low drag hull designs or "slow steaming", but the actual ship material isn't terribly high up on the priority list. And aluminium is way more expensive.

scythe 2y ago

>Unlike solar cells or battery cells, I don't really see much chance for 'learning rates' and technology improvement to drastically drive down the cost of green ammonia. Falling electrolyser costs are nice, but they're only a portion of the process plant CAPEX, and the cost of the green electricity dominates the economics over the process plant CAPEX anyway. You could get electrolysers for free and still be unable to make cheap green ammonia. So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. There is a ton of research going into improving the efficiency of the H2 > NH3 conversion, and there are at least two startups (Tsubame in Japan and a new one I don't remember). There's no rule that says you can't beat Haber. Compared to methanol, ammonia is currently more expensive but vastly more scalable in the long run; once you reach the biofuel "ceiling" (roughly corresponding to the availability of farming and forestry byproducts) you're stuck making it via carbon capture, which has its own efficiency problems.

kragen 2y ago
By "efficiency" do you mean energy consumption or hydrogen consumption?
- scythe 2y ago
  Energy consumption. I am pretty sure that the hydrogen utilization in most ammonia production is very high. In theory the energy required to produce ammonia is negative (Hf < 0) but at standard pressure its formation is thermodynamically unfavorable (Gf = Hf + TdeltaS > 0). But the bigger issue is the very high activation energy barrier for ammonia synthesis, which results in a lot of energy being used to make ammonia at very high pressure and temperature. Right now there are two competing approaches to reducing the cost of ammonia production. Tsubame is using a new ruthenium-based catalyst that lowers the reaction temperature (and therefore, also the pressure). The other method is by electrocatalysis. I don't know for sure that this is what NitroVolt is doing but their name certainly suggests it.
  - kragen 2y ago

Anduia 2y ago

That linkedin post seems AI generated, got a better source?

jgraham 2y ago

Note that biofuels aren't especially environmentally friendly, even just considering carbon emissions. See e.g. [1], which makes the most optimistic possible assumption by ignoring land use changes and still concludes "the reductions for most feedstocks are insufficient to meet the GHG savings required by the EU Renewable Energy Directive" (second generation biofuels may do better, but that isn't clear). Also ignoring land use changes is a very bad asssumption; if your plan is to run global shipping (or other industries) on biofuels it seems highly implausible that it's not going to end up with more land overall used for growing crops. If that's land that could otherwise be sequestering carbon (e.g. drained peat bogs, which have the advantage of being highly fertile), then it's clearly going to be a significant contribution to carbon emissions (not to mention the ecological impacts of converting yet more land to agriculture). [1] https://royalsocietypublishing.org/doi/10.1098/rspa.2020.0351 https://royalsocietypublishing.org/doi/10.1098/rspa.2020.035...

kragen 2y ago

> Unlike solar cells or battery cells, I don't really see much chance for 'learning rates' and technology improvement to drastically drive down the cost of green ammonia. Falling electrolyser costs are nice, but they're only a portion of the process plant CAPEX, and the cost of the green electricity dominates the economics over the process plant CAPEX anyway. (...) So for green ammonia to get adopted, a strong 'carbon price' needs to be in place, and I think that same strong carbon price would make biodiesel competitive. You seem to be contradicting yourself here? If learning rates and technology improvement drastically drive down the cost of solar cells, as you say they might, and the cost of electricity dominates the cost of green ammonia, as you say it does, doesn't that mean that the learning rates and technology improvement in solar cells will drastically drive down the cost of green ammonia? Wouldn't that make ammonia much cheaper than biodiesel, keeping biodiesel from being competitive? (I'm not sure ammonia is a competitive fuel for other reasons, such as the corrosion and safety issues discussed in the article, but it seems clear to me that if it's going to be uncompetitively expensive, it would have to be because one of the premises above is wrong, for example because the cost of green ammonia is dominated by capex or because solar cells stop dropping in cost. I don't see how you can sustain those premises and deny the conclusion.)

whatever1 2y ago

At this risk envelope I don’t see why nuclear / battery hybrids are not a serious contender. We can for example have them work on purely electric mode when close to ports and then enable the reactor in the open sea. We do something similar with bunker fuel of different grades. They are forced to use the good stuff near the ports and once in the open sea they start burning the muddy Godzilla.