Fossil Fuels Are 40% of Freight Shipping Tonnage, but Half Its Fuel Use

The top graph makes it seem much more dramatic than it is.

Maritime shipping is very efficient, and consists of a very small fraction of overall petroleum usage.

Road transportation uses about 20x as much fuel as ocean shipping, planes use about 2x as much, and trains about the same amount.

The typical rule of thumb is that about 40% of the energy in a barrel of petroleum is lost before it goes into your gas tank. And the two big factors are the energy required to do the refining and delivering the fuel from the refinery to the gas station. Shipping the crude from the oil field to the refinery is a factor, but a small one in comparison.

This 40% is the main reason why driving an EV emits less carbon than driving an equivalently sized gas vehicle even if you're topping up that EV with the dirtiest electricity you can find.

P.S. maritime shipping typically uses very dirty fuel. We'll probably notice the reduction in sulfur pollution more than the reduction in CO2.

P.P.S 3% of a very large number is still itself a large number, so it's still worth looking for solutions.

Oh wow, that's far higher than I've been using in my estimates, I'd been rounding down to 1/3.

The massive reduction in oil supply from the sudden and unexpected closure of the Strait of Hormuz, with gas prices jumping but minimal economic contraction, has been great evidence that we could perform a global energy interchange far faster than anybody ever expected without causing massive damage.

However, the pushback I've been hearing a lot is that ocean freight still needs fossil fuels, that's always going to be a blocker.

In reality, it's only ~1% of emissions, and half of it goes away when we stop other uses, so solving that 0.5% of fossil fuel use, or even still emitting it, is really a rounding error. (And methanol or ammonia as well as other synthetic fuels based off hydrogen production have a great chance of stepping into that, especially as we massively scale ammonia production from electrolyzers, which also solves the fertilizer that has been caused by closing the Strait of Hormuz).

Fossil fuel based economies are inherently fragile and bound to massive price increase cycles. Changing our economies to be powered by renewables and storage will be far more stable, cheaper, and bring a massive increase in economic output. We can't switch fast enough.

To summarize: 40% of tonnage but 50% of tonnage-kilometres. I thought freight volume would be measured in ton-kilometres in the first place.

The headline is only surprising if shipping is the majority of fuel use.

It isn’t. In the limit, if it were 100% of fuel use, then we’d be burning 1.2 gallons of fossil fuel to deliver 1 gallon, which clearly wouldn’t work.

A much better question is “what percentage of the embodied carbon for this good is from freight shipping”? The answer is almost always very low because last mile shipping dominates, and so does manufacturing the item. For fossil fuel, those things dominate, and so does the step where the customer burns the fuel.

Basically, the entire article is confused because it doesn’t start with the fossil fuel equivalent of Amdahl’s Law.

What the hell is this headline and the article trying to say..?

"40% of horse-drawn carriage cargo is hay, but 50% of what we feed horses is hay".

So what?

The chart at the top of the article makes it clear that the entire thing is pure fantasy

The top graph makes it seem much more dramatic than it is.

Maritime shipping is very efficient, and consists of a very small fraction of overall petroleum usage.

Road transportation uses about 20x as much fuel as ocean shipping, planes use about 2x as much, and trains about the same amount.

This 40% is the main reason why driving an EV emits less carbon than driving an equivalently sized gas vehicle even if you're topping up that EV with the dirtiest electricity you can find.

P.S. maritime shipping typically uses very dirty fuel. We'll probably notice the reduction in sulfur pollution more than the reduction in CO2.

P.P.S 3% of a very large number is still itself a large number, so it's still worth looking for solutions.

Why is the EV better? Because electricity transmission is more efficient than gas? What about the losses in the electricity transmission and the batteries and the conversion to motive force in the motor? Is it way less than that 40%? And wouldn’t there be more than 0% losses because refinery -> power plant shipping?

I’m pro EV by the way, I just want to understand your point better. Being able to go all the way to transportation using clean energy is an obvious benefit of EVs. The “dirty electricity” angle is less obvious to me.

The chart at the top of the article makes it clear that the entire thing is pure fantasy

The headline is only surprising if shipping is the majority of fuel use.

It isn’t. In the limit, if it were 100% of fuel use, then we’d be burning 1.2 gallons of fossil fuel to deliver 1 gallon, which clearly wouldn’t work.

Basically, the entire article is confused because it doesn’t start with the fossil fuel equivalent of Amdahl’s Law.

What the hell is this headline and the article trying to say..?

"40% of horse-drawn carriage cargo is hay, but 50% of what we feed horses is hay".

So what?

Oh wow, that's far higher than I've been using in my estimates, I'd been rounding down to 1/3.

However, the pushback I've been hearing a lot is that ocean freight still needs fossil fuels, that's always going to be a blocker.

To summarize: 40% of tonnage but 50% of tonnage-kilometres. I thought freight volume would be measured in ton-kilometres in the first place.

I swear to God, I've read the article twice and I've read the comments replying to your question and I still have no idea.

I think the problem is that, for any given sentence, it is unclear whether the author is talking about the fuel a ship is burning to move its cargo, or fuel that the ship is transporting to a destination.

I do understand that the article is making some kind of distinction between the two, but it is so terribly written that it's just impossible to figure out which one it's talking about at which point. Or at least I certainly don't care to waste my time "solving" the article like it's some kind of linguistic puzzle.

I'm not sure I've ever come across an article that needed an editor to improve its clarity more than this one.

It's saying that 40% of the tons of cargo loaded onto ships is fossil fuels, but this makes up about 50% of ton-miles, because fossil fuels travel further on average than other cargo. Not the easiest headline to correctly parse.

It means in the long term there might be more efficient ways to ship 'energy'. If you ship containers full of solar PVs, batteries and use it over their lifetime the amount of 'total energy' transported for a given unit of energy to transport the materials might be an order of magnitude or more higher

From the fucking article: Fossil fuel cargoes travel long distances in very large flows, so their decline removes more than a proportional share of cargo mass. It removes a larger share of the ocean work and the fuel burned to do that work.

And if I can get on my soapbox. This same problem (carrying fuel to feed the transportation unit) is well studied in medieval England because it was one of the main determinants of where cities and castles were placed (albeit unknowingly at the time). And we see what happened in England when they were able to get out from under feeding oxen.

That is not what I understood from the article. What I understand is:

Fossil fuels are 40% of freight tonnage, but transporting them fuels is responsible for 50% of the total freight fuel consumption.

I assume 99% of freight uses fossil sources as fuel.

It’s trying to say what if we didn’t have to haul energy around from place to place but generate it closer to consumption - we could move more useful stuff instead.

It is so weird that it makes 40% sense of 50% its length.

The preposition ("butt") is wrong

Where are all of the emissions coming from? I keep hearing that automobiles account for a small % and that trucking and shipping account for the majority, but you're saying shipping is only 1%.

To further give context: the article is saying that most of the fuel transported around is done for long distances, so when something removes fuel use in the consumer side it has a double dip effect: less fuel consumed and less fuel used to transport the fuel, since long fuel supplies route diminish. It's a third order of thinking and that's why it's confusing. The article then argues that reducing that consumption in the buyers side is more effective:

> This is the part that fuel-first narratives tend to miss. In a serious energy transition, coal demand falls, oil demand falls, and gas demand falls. That means fewer bulk carriers and tankers moving fossil energy around the world. The maritime sector does not have to find a one-for-one replacement fuel for all of that work, because a material share of the work should disappear.

I would argue that chipping away at all three sides of the equation reducing the amount of fuel used, the amount of fuel used for transport and transporting things using other that fuel are worth pursuing.

In an EV about 90% of the energy used is converted into motion. About 10% goes to heat. [1][3]

In an ICE engine about 30% of the energy becomes motion. About 70% is heat.[2]

In other words electric motors are about 3 times more efficient than ICE.

[1] an interesting side effect of this is that in cold climates you can't just harvest waste heat to heat the cabin (or batteries. ) So you end up using some battery energy if you need heat.

[2] ICE motors vary in effeciency a lot. 20-30% is typical. The Carnot formula comes into play here.

[3] because there is so little heat generated, the cooling systems (EVs still have them) are much smaller. And simpler (for example, no fan, 'cause there's no heat when standing still.)

Transmission losses are orders of magnitude lower than transportation energy costs. You both get dramatically less loss per kilometer, and you have way fewer kilometers to travel. Transmission does get less efficient over longer distances; if you had a 20000km long transmission line it would be less efficient than shipping fossil fuels, but you simply don't need to do that.

You have conversion losses to generate motion but these are again substantially less than the conversion of chemical energy to motion that occurs inside a combustion engine. Powerplants+electric motors will have conversion efficiencies around 30%; internal combustion engines will have conversion efficiencies around 10%.

With the exception of some remote locations or emergency situations with backup generators, you are almost certainly not consuming a fuel that requires refining to generate electricity. If you're burning coal or gas, it's coming from much closer, and it's being transported in bulk to the powerplant. Trucks taking fuels to the local distribution centers and ultimately gas stations are by far the largest transportation energy expense for petrol.

It's a bit hard to answer the "dirtiest fuel you can find" case specifically, because there are a number of areas where EVs are more efficient. The biggest difference is probably the fact that the internal combustion engine in a car is about 25% efficient, though it depends on the RPM it is running at etc (the reason hybrids can push it up to ~40-ish% depending on how new they are is because the engine is always running at the most efficient RPM when it runs), but the "dirtiest power" specifically would probably be a coal plant which is only about 30% to 40% efficient (9000 to 11000 BTU/kWh in imperial units) due to low temperatures and the inability to run it as a 2-stage, combined-cycle sort of setup (modern combined-cycle gas turbines are ~60% efficient which is one contributing factor to gas-based electricity being cheaper even though gas costs more per GJ, though since the price of natural gas is quite volatile that sometimes changes). Of course the transportation is different depending on which fuel is used for a power plant.

In the worst-case scenario, accounting for the ~90% efficiency of the electric motors... Well, Xunmin et al. (2005) estimates 3–36%, so lifecycle emissions could be reduced by as little as 3% if you power it 100% by coal, which would be less than the what you'd get from a hybrid, but... You're not really going to find a power grid that is powered 100% by coal these days, even in China. Really the biggest advantage of a BEV, and any other electrification, is that if there are future investments in the grid (and there will be since generators don't last forever) you don't have to replace the engine of your car for it to automatically reduce emissions. The efficiency gains are just a cherry on top.

[Xunmin]: https://www.sciencedirect.com/science/article/abs/pii/S17505...

As I understand it, it's a mix of factors.

Charging Lithium, and converting to motive force in motors are both pretty efficient. (Both >90%).

An ICE vehicle has an upper limit on efficiency that is lower than what a modern fossil fuel plant can reach, and the ICE is less likely to sit at peak efficiency all the time. The world record, set this year was 48%. Previously, it was 41%.

Power plants are much more likely to be kept at or near their peak efficiency and have the space for systems like heat recovery (to recapture waste heat) and emissions controls. For a gas turbine plant, I think the record is ~64% sustained.

>> The “dirty electricity” angle is less obvious to me.

A power plant typically gets about 60% of energy from a fossil source. A car does about 30%. So even if the electricity comes from say coal, it's still more efficient than buying gas in a car engine.

Of course, these days, it's likely that a substantial portion (up to 100% in some cases) is not "fossil electricity" but rather comes from solar, wind, hydro etc. Ie "clean" electricity.

Grid loss is maybe 5%.

The important driving factor is that generation becomes more efficient when you can use natural gas to turn turbines directly and then capture the waste heat to boil water and turn turbines with steam. This is called combined cycle if you want to google it to learn more.

Another thought exercise, if generating electricity with fossil fuels wasn’t more efficient at scale, why would we bother building a grid in the first place? Every house would just have a gas generator.

I swear to God, I've read the article twice and I've read the comments replying to your question and I still have no idea.

I'm not sure I've ever come across an article that needed an editor to improve its clarity more than this one.

I read this and another half-dozen replies to the parent comment (but not the article, of course...) and was still confused. This comment was the clearest to getting me to understand it.

Example contributors as I presently understand it:

- we transport fossil fuels further around world (i.e. Middle East to the US)

- we transport most other goods some shorter distances

- iron ore transport is "up there" with fossil fuels; high ton-miles of transport.

And of course the cost of transport for a good is a function of distance, a la the rocket equation mentioned in other comments.

And the article is focused on making this point in the context of the effect of reduced demand for fossil fuels and steel (iron ore) on maritime demand. (which is interesting, and totally not what the article title was leading my brain to think about)

Edit: And then I went and actually looked at the figure at the top of the article; guess the real topic is yet a different framing than what I comment on above!

It’s trying to say what if we didn’t have to haul energy around from place to place but generate it closer to consumption - we could move more useful stuff instead.

It is so weird that it makes 40% sense of 50% its length.

That is not what I understood from the article. What I understand is:

Fossil fuels are 40% of freight tonnage, but transporting them fuels is responsible for 50% of the total freight fuel consumption.

I assume 99% of freight uses fossil sources as fuel.

So basically a very friendly version of the rocket equation.

> It removes a larger share of the ocean work and the fuel burned to do that work.

Sure, but as long as ratio of fuel moved:fuel used is good enough, people won't care (as demonstrated by historical data). This isn't an argument that leads to change. For those not already convinced of the climate crisis, you'll need to lean on economics.

See also Coals from Newcastle.

Are you making a reference to the Tyranny of the Rocket Equation? The Earth's gravity is so large that it's almost at the limit of chemical rockets. A typical rocket is 90% propellant by mass, 8% structure and 2% payload.

[Xunmin]: https://www.sciencedirect.com/science/article/abs/pii/S17505...

As I understand it, it's a mix of factors.

Charging Lithium, and converting to motive force in motors are both pretty efficient. (Both >90%).

The other nice thing is that the batteries on cars can effectively act as grid energy storage even without v2g. Simple offpeak/low rate charging setups can take the most efficiently generated cheap power.

In Australia power prices are often negative in the day due to solar and there's various variable rate plans you can get to take advantage (Australia dwarfs all other nations in per capita solar; even China is nowhere close per capita). I know workplaces that will actively encourage you to charge your car at work.

Power prices due to the excess solar keep falling - eg. 10% fall nationwide in July (middle of winter in Aus so not even near peak solar). https://www.theguardian.com/australia-news/2026/may/26/power...

For all the talk of 'solar can't replace fossil fuels' or 'electricity isn't green' Australia's gone and created a nation wide energy market that encourages rooftop solar and it's found itself with excess daytime energy at a time when the world has an energy crisis in Iran and the datacenters going up everywhere.

In an EV about 90% of the energy used is converted into motion. About 10% goes to heat. [1][3]

In an ICE engine about 30% of the energy becomes motion. About 70% is heat.[2]

In other words electric motors are about 3 times more efficient than ICE.

[1] an interesting side effect of this is that in cold climates you can't just harvest waste heat to heat the cabin (or batteries. ) So you end up using some battery energy if you need heat.

[2] ICE motors vary in effeciency a lot. 20-30% is typical. The Carnot formula comes into play here.

[3] because there is so little heat generated, the cooling systems (EVs still have them) are much smaller. And simpler (for example, no fan, 'cause there's no heat when standing still.)

Who cares about motor efficiency when you can only take 10% as much fuel. At the end of the day, cost is the only metric that matters.

>> The “dirty electricity” angle is less obvious to me.

A power plant typically gets about 60% of energy from a fossil source. A car does about 30%. So even if the electricity comes from say coal, it's still more efficient than buying gas in a car engine.

Of course, these days, it's likely that a substantial portion (up to 100% in some cases) is not "fossil electricity" but rather comes from solar, wind, hydro etc. Ie "clean" electricity.

The preposition ("butt") is wrong

Grid loss is maybe 5%.

Where are all of the emissions coming from? I keep hearing that automobiles account for a small % and that trucking and shipping account for the majority, but you're saying shipping is only 1%.

Our energy aggregator is a non-profit Community Choice Aggregator with over 250,000 members that ensures 50% of the energy they purchase comes from renewables and 75% of all energy purchased is carbon free. And for an extra $0.00750 p/kWh you can opt into your consumption coming 100% from renewable sources.

I wonder if this actually has the potential to have the opposite effect.

If an oil producer electrifies faster than average, for example Norway, then oil that might have been consumed domestically instead is shipped overseas.

It’s also a clue as to why there’s such serious political opposition to wind and solar and to some extent nuclear for electric generation.

Point of use generation is disruptive to many industries… not just petroleum but automotive, trucking, various services that serve both, etc. There’s a significant portion of the population employed by schlepping oil around and doing things with it to support those activities.

There is no mention of the amount of fuel used to transport the fuel in the article. From what I know it’s a tiny fraction: boats are efficient at transporting stuff (slowly)

I kind of read this

> Fossil fuels are roughly 40% of maritime tonnage, but in the model they represent about half of maritime freight energy because coal, oil, and gas are mostly long-haul bulk trades. Moving a ton of scrap metal a short distance and moving a ton of oil or LNG across oceans are not the same transport-energy problem, even if both show up as one ton in a cargo table.

as being exactly what was being talked about... more fuel is spent on transporting fuel due to distance it travels.

but your comment made me re-visit (i.e. more closely skim...) the article, and it's really about: "as the demand for fossil fuels is projected to decrease, (1) less long-haul shipping is needed and (2) a greater fraction of shipping will be short-haul, which will be practical for other types of freight fueling (i.e. what's shown in the figure at the top of the article)

I have no sense of how realistic the figure is. For example, I don't know the current projections for decline of fossil fuel demand over ?? year timeframe.

Yes it’s a reference to the tyranny of the rocket equation. The same principle applies to wagon logistics because the animals and driver are constantly eating the food the wagons carry.

FTA: "We may call this problem the ‘tyranny of the wagon equation’ as a number of readers have noticed the similarity to the tyranny of the rocket equation."

It's mathematically very similar.

I’ve wondered if this belongs on the Fermi paradox pile. Many biospheres may be more massive planets that are so hard to get off that a space enterprise never starts.

Meanwhile lighter planets might have trouble holding onto atmospheres.

Who cares about motor efficiency when you can only take 10% as much fuel. At the end of the day, cost is the only metric that matters.

The cost of EV energy (to the driver) is about half that of the cost of gas energy. And that's if you buy electricity at charging stations [1].

If you charge at home it gets less. If you have solar at home it approaches zero.

Yes, the cost of the car itself is a factor, but even there prices are dropping all the time.

>> when you can only take 10% as much fuel

effeciency makes all the difference when we discuss % of fuel. 90% of 100 mj is the same as 30% of 300 mj. So already the "fuel" can be 66% less. Generally though the raw amount of mj isn't a very important number. A better measure (which takes effeciency, and tank size into account) is "range". But even that is somewhat meaningless. At some point range is "enough". For daily commutes that may be 50 miles. For long-distance it might be 500 miles.

In only a very few cases would a pickup with 2000 mile range be more useful than one with 1000 mile range.

Plus you can also factor in maintenance costs. The cost of ownership of an ev, from a service and maintenance point of view is a lot lower.

[1] ymmv somewhat. Although electricity prices vary a lot, so do gas prices. The 50% saving (at worst) is a pretty good rule of thumb though.

My xpeng g9 goes about 570km in summer. Less in winter, like 480 maybe. Longest range ICE i had was a mercedes wagon that went 1050km on one tank of gas.

Filling the wagon today would cost me like 170 euro. Filling my xpeng happens overnight and is about 7-9 euro depending on grid pricing.

> cost is the only metric that matters.

Negative externalities like pollution and climate change are not even priced in. Even if they were priced in, there are non-monetary factors that we could consider once in a while, but the conversation tends back to dollars.

The commenters above, is the answer to your question. Based on their discussion, there are metrics besides cost that matter to them.

Not everyone is you.

I wonder if this actually has the potential to have the opposite effect.

If an oil producer electrifies faster than average, for example Norway, then oil that might have been consumed domestically instead is shipped overseas.

I’ve wondered if this belongs on the Fermi paradox pile. Many biospheres may be more massive planets that are so hard to get off that a space enterprise never starts.

Meanwhile lighter planets might have trouble holding onto atmospheres.

It’s also a clue as to why there’s such serious political opposition to wind and solar and to some extent nuclear for electric generation.

Yes it’s a reference to the tyranny of the rocket equation. The same principle applies to wagon logistics because the animals and driver are constantly eating the food the wagons carry.

It's mathematically very similar.

I kind of read this

as being exactly what was being talked about... more fuel is spent on transporting fuel due to distance it travels.

I have no sense of how realistic the figure is. For example, I don't know the current projections for decline of fossil fuel demand over ?? year timeframe.

I don't disagree with you but every country is different. Australia gets a lot of sunshine and is sparsely populated, so plenty of room for solar anyway. This is not the case everywhere though.

It can be a good example though of how you overproduce during the day and use that to charge car batteries for example

FTA: "We may call this problem the ‘tyranny of the wagon equation’ as a number of readers have noticed the similarity to the tyranny of the rocket equation."

My xpeng g9 goes about 570km in summer. Less in winter, like 480 maybe. Longest range ICE i had was a mercedes wagon that went 1050km on one tank of gas.

Filling the wagon today would cost me like 170 euro. Filling my xpeng happens overnight and is about 7-9 euro depending on grid pricing.

The commenters above, is the answer to your question. Based on their discussion, there are metrics besides cost that matter to them.

Not everyone is you.

> cost is the only metric that matters.

Many countries have high fuel taxes that approximate pricing in the negative externalities.

Assuming you think price as a signal is the solution to dealing with those externalities, it doesn't matter what caused the price to be high.

The cost of EV energy (to the driver) is about half that of the cost of gas energy. And that's if you buy electricity at charging stations [1].

If you charge at home it gets less. If you have solar at home it approaches zero.

Yes, the cost of the car itself is a factor, but even there prices are dropping all the time.

>> when you can only take 10% as much fuel

In only a very few cases would a pickup with 2000 mile range be more useful than one with 1000 mile range.

Plus you can also factor in maintenance costs. The cost of ownership of an ev, from a service and maintenance point of view is a lot lower.

[1] ymmv somewhat. Although electricity prices vary a lot, so do gas prices. The 50% saving (at worst) is a pretty good rule of thumb though.

Indeed, solar panels and EVs are the way of the self-sufficient rugged individualist. It's an amazing PR and marketing coup to make it the other way around and presented as something for "liberal weaklings" etc.

I don't disagree with you but every country is different. Australia gets a lot of sunshine and is sparsely populated, so plenty of room for solar anyway. This is not the case everywhere though.

It can be a good example though of how you overproduce during the day and use that to charge car batteries for example

Many countries have high fuel taxes that approximate pricing in the negative externalities.

Assuming you think price as a signal is the solution to dealing with those externalities, it doesn't matter what caused the price to be high.

Right, the set of people who actually pump their own oil out of the ground, refine it into something you can put in a modern vehicle engine and drive around on that is likely zero, but the set of people who own panels and storage so they can fill their EV includes my team lead, who is just some guy on a pretty average salary living on a modern housing estate.

The bio-fuel people at least make some kind of sense compared to fossil fuel "survivalists" - but again they're portrayed as just tree huggers!

Shipping’s transition starts by shrinking the fuel pool, then using electrons and scarce liquids only where they fit.

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Maritime fuel debates usually start with the wrong object. They look at today’s bunker fuel demand, line up replacement molecules, and ask whether ammonia, methanol, hydrogen, LNG, biofuels, or synthetic fuels can scale far enough to replace it. That sounds like a practical question, but it skips the larger one: how much maritime fuel demand remains after the energy transition changes the cargoes that ships carry.

The important result from my rebaselined maritime energy pathway is that fossil fuel cargo is not just large by mass. It is disproportionately important to shipping energy. Fossil fuels are roughly 40% of maritime tonnage, but in the model they represent about half of maritime freight energy because coal, oil, and gas are mostly long-haul bulk trades. Moving a ton of scrap metal a short distance and moving a ton of oil or LNG across oceans are not the same transport-energy problem, even if both show up as one ton in a cargo table.

That distinction matters because shipping fuel demand is driven by transport work, not just tons loaded at ports. Ton-kilometres are the better mental model. Fossil fuel cargoes travel long distances in very large flows, so their decline removes more than a proportional share of cargo mass. It removes a larger share of the ocean work and the fuel burned to do that work.

This is the part that fuel-first narratives tend to miss. In a serious energy transition, coal demand falls, oil demand falls, and gas demand falls. That means fewer bulk carriers and tankers moving fossil energy around the world. The maritime sector does not have to find a one-for-one replacement fuel for all of that work, because a material share of the work should disappear.

Raw iron ore is the adjacent exposed category. It is not part of the 40% fossil-fuel tonnage number, but it is another large, long-haul bulk trade tied to the old industrial geography. As China’s construction pulse slows, steel demand shifts, scrap use rises, electric arc furnaces take more share, and more iron reduction can occur closer to renewables-rich mining regions, raw iron ore shipping is unlikely to behave like a permanently rising global constant. That does not make iron ore shipping vanish, but it does make it a poor basis for assuming today’s bulk-shipping energy demand simply continues.

Other parts of shipping grow in the transition, but many of them are better suited to electrification than the fossil-bulk trades they partially replace. Offshore wind construction and service vessels grow. Ferries and short-sea routes expand where road congestion, urban growth, islands, ports, and regional logistics justify them. Inland and coastal freight can grow as supply chains reorganize and ports electrify. These are not all battery-only segments, but they tend to have more regular routes, shorter distances, known terminals, and better opportunities for charging, shore power, and battery-dominant hybrid operation than long-haul coal, oil, gas, and raw iron ore trades.

The result is a very different maritime fuel problem. A one-for-one substitution model makes the alternative-fuel task look enormous, and it is enormous if the goal is to preserve today’s oil-shaped marine energy system with different molecules. A denominator-first model asks what fuel-burning work is left after fossil cargo declines, raw iron ore exposure is included, electrifiable segments grow, short routes electrify, and efficiency trims the remaining fleet.

That is where batteries enter the picture without pretending to be magic. Inland shipping, ferries, harbor craft, many short-sea routes, and some coastal services are structurally suited to batteries, shore power, terminal charging, and battery-dominant hybrid operation. Recent work in Nature Energy on short-sea electrification found a surprisingly large eligible wedge of maritime energy once route structure, battery size, ship classes, and operating patterns are tested rather than waved away. Those ships do not need a universal global molecule. They need electricity, charging infrastructure, operational planning, and procurement discipline, which is less glamorous than a new global fuel chain and usually more useful.

Operational efficiency also matters, but it belongs in the same denominator logic. Slow steaming, routing, hull management, propeller improvements, wind assistance where it fits, hybridization, and better logistics all reduce fuel demand in the part of the fleet that still burns fuel. None of them turns a large oceangoing vessel into a battery ferry, and none of them avoids the need for residual liquid fuels. They reduce the size of the problem those fuels have to solve.

Only after those reductions does the residual fuel debate become useful. Biomethanol, biodiesel, hydrotreated vegetable oil, and potentially ethanol belong in the conversation for vessels and routes that still need liquid fuels and where feedstock, lifecycle emissions, bunkering, safety, and cost make sense. They do not have to replace today’s entire marine fuel pool to matter. They have to serve the smaller pool of voyages that still need energy-dense liquids after cargo, route, and efficiency changes have done their work. In that context, hybrid ships make alcohol fuels range extenders, not rivals to electrification.

That is one reason ammonia and hydrogen remain weak centerpieces for shipping decarbonization. They ask the sector to build expensive new fuel chains around molecules with major cost, safety, energy-density, handling, and lifecycle-accounting problems, often while ignoring the shrinking denominator. Synthetic fuels have their own very long electricity and conversion-loss stack. LNG remains mostly a fossil incumbent strategy with a different label and a methane problem it has never convincingly escaped.

The policy discussion is slowly moving toward better accounting, especially with well-to-wake emissions and tighter International Maritime Organization targets, but targets do not create viable fuel pathways by themselves. Alternative-fuel capability on a ship order is not delivered decarbonization. A pilot bunkering event is not fleet transformation. The useful evidence comes later: operating routes, delivered fuel, verified lifecycle emissions, repeat procurement, and economics that survive outside demonstration conditions.

The public reading of the pathway is straightforward. Count fuel only where ships remain fuel-burning. Discount the parts of shipping where cargo disappears, where batteries and shore power are advantaged, and where operational changes reduce energy use. Then argue about residual liquids for the work that remains, not for the entire legacy bunker-fuel pool. That is also how maritime fuel economics should be compared: by useful work and residual demand, not by preserving today’s fuel pool and asking every molecule to fill it.

Shipping is not going to decarbonize by finding one universal alternative fuel and applying it to the existing oil-shaped system. It has to recognize that some of today’s largest and most energy-intensive cargo flows are structurally exposed by the transition itself. When 40% of tonnage represents about half of freight energy, the first fuel transition is not a molecule. It is the disappearance of a lot of long-haul fossil work.

A longer maintained version of this analysis is available at TFIE Strategy Briefing:

Shipping’s Fuel Transition Starts With Less Fuel, Not Better Molecules

It is part of Michael Barnard’s broader work on maritime decarbonization, shipping fuel pathways, electrification, residual liquids and 2100 transition scenarios.

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Fossil Fuels Are 40% of Freight Shipping Tonnage, but Half Its Fuel Use

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