Fossil Fuels Are 40% of Freight Shipping Tonnage, but Half Its Fuel Use(cleantechnica.com) |
Fossil Fuels Are 40% of Freight Shipping Tonnage, but Half Its Fuel Use(cleantechnica.com) |
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.
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.
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.)
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...
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.
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.
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 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.
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.
> 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.
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.
"40% of horse-drawn carriage cargo is hay, but 50% of what we feed horses is hay".
So what?
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.
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!
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.
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.
The Tyranny of the Wagon
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.
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.
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.
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.
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.
Not everyone is you.
Meanwhile lighter planets might have trouble holding onto atmospheres.