Cars, trucks and planes get plenty of blame for helping drive the climate crisis, but shipping produces a large portion of the world’s greenhouse gases, as well as nitrogen oxides and sulphur pollution because ships largely use cheap heavy fuel oil.
Large potion? 2% if you’re lucky. It’s a triviality – as well as being the most fuel efficient form of transport ever. Further, the reduction in emissions by doing things in efficient places to do that thing is vastly greater than the emissions from the shipping. We do know this – eery study of the effects of putting that Pigou Tax on the emissions from shipping shows that shipping would still continue.
This is just more of the usual bollocks. The noodle-armed think international trade is bad therefore blah blah blah any excuse.
Just Stop Living
Surprised the Guardian doesn’t seize the opportunity to have a pop at cruise ships.
Even the sulphur pollution bit is bollocks – the IMO banned use of high sulphur fuel without exhaust scrubbers back in 2020.
Forgot to add: as was reported in the Guardian at the time.
NOOOO!
Global Warming Scientists insist we’ll all be saved if we grind up trees in the USA with bloody great mincers and ship the low calorific wood 4,000 miles to burn it in the UK!
And they crossed their hearts!
I like cars and trucks and planes. Not too keen on trains and ships as a form of travel but I know they make the world better. I like meat and crops grown with fertilizer. Not too keen on weedkillers but I know they make the world a better place. I like Western civilization too.
Now what do these bastards propose as a replacement for all the things I like? What is their idea of a better world? And if I don’t fancy it, who do I vote for?
Now what do these bastards propose as a replacement for all the things I like?
Pyramids of human skulls, but dyed in the colours of the LGBTQIA/BLM flag.
There’s an opportunity for extreme pendency here. Any vehicle in motion has to displace its cross sectional area of the fluid it’s travelling through. Known as drag. So for a ship one can envisage that as water, the cross section of the hull, extending from the port of departure to the port of arrival. That is a considerable mass of water when you’re talking thousands of miles of it. An aircraft has to do exactly the same. It also has to displace air for the cross sectional area of the hull above water, but let’s ignore that.
Similarly, an aircraft travelling in the stratosphere has to do the same. But air being much less dense than water, for the same expenditure you far greater distance. So airfreight would be more energy economical than seafreight. It’s the practicalities that prevent it.
“So airfreight would be more energy economical than seafreight.”
If it wasn’t for that pesky gravity.
@rhoda “And if I don’t fancy it, who do I vote for?” – what difference is voting supposed to make? You can’t put a fag paper between any of them. On the rare occasions when the wrong result is delivered, the result is ignored/deflected/diverted back on to the right track.
I’m going to stop now, I feel a rant coming on 🙂
HexChopper – Lions.
Pass it on.
Hex,
As I read it, that’s Rhoda’s point, well made as ever.
If it wasn’t for that pesky gravity.
Not very good at physics are you Steve? Sure, an aircraft produces parasitic drag from displacing the mass of air holds it up. That’s included in the cross sectional area. The energy expended getting it to altitude is recovered as it descends. That’s how a plane comes down. You throttle back & trade altitude for flight distance.
For the avoidance of doubt, I think rhoda and I are on exactly the same page, I needed to just to chime in to vent some of my considerable amount of frustration 🙂
It’s exactly the same drag as the water holds a ship up against gravity imposes. But less, because the density of the air in the stratosphere is far smaller than the Atlantic.
It’s scale. If you were shifting seafreight in 150 ton freighters you wouldn’t benefit from the economies of scale. if you were building 100,000 ton aircraft you would.
. . . extreme pendency . . .
. . . requires even misused words left hanging be correctly spelled.
– if you were building 100,000 ton aircraft you would.
Odd that no one does that then.
BiS – Do you really think moving 4,500 TEU of cargo thru the stratosphere is going to use less energy than putting it on a slow boat from China?
The energy expended getting it to altitude is recovered as it descends
What madness is this?
Yes, energy can’t be created or destroyed, but we’re playing a losing hand against entropy. Cargo planes don’t get to turn off their jet engines and glide, do they? They’re constantly burning fuel to maintain airspeed.
We know the sea is a more efficient route than the air, because it’s cheaper.
Pendenty better? My spell checker doesn’t like any of them.
eery(sic) study of the effects of putting that Pigou Tax on the emissions from shipping shows that shipping would still continue
Pigou taxes again. Now tell us, Tim, how those studies calculated the externalities of shipping freight emissions? On some IPCC fantasy numbers? Because they’re not actually known are they? Not within an order of magnitude or two. Not even whether they’re positive or negative. So it’s not a Pigou tax. It’s a revenue raising tax with a built in alibi. Pigou taxes are economists’ wibble.
– Pendenty better? My spell checker doesn’t like any of them.
Polly spells it out in the vainglory section. By strange coincidence directly to the right of your comment on my screen.
– So it’s not a Pigou tax.
A Pigouvian tax doesn’t have to be set against an objective measurement, or even against something objective at all. If you taxed gangsta rap because it has the negative externality of being offensive shite at any decibel level, that would be a Pigou tax.
One of the best acquisitions I’ve ever made is my boat with a 3.4l V6 225hp american-built outboard engine
I did notice that when the Suez Canal was blocked, after the 1967 war I believe, they just built super-tankers to ship the oil cheaply around the Cape. Cheaper than a war.
They certainly didn’t attach sails to the ships.
“Already more than 20 commercial cargo ships use wind power to cut their fuel use, and more are being launched, but it is taking a long time for wind power to become widely accepted in the industry.”
Let’s not hold our breath, eh?
Rough estimate that transport by sea is about 15x-20x more efficient (in kg/Joule) than by air.
And here’s ChatGPT’s opinion…
Q: Please estimate the kilogram/Joule of transporting cargo by air and by sea
A: Sure, here are some rough estimates of the energy efficiency of transporting cargo by air and by sea, expressed in kilograms per Joule (kg/J):
Transporting cargo by air:
On average, a cargo airplane consumes around 16-20 liters of fuel per 100 tonne-kilometers (tkm) flown. Assuming a fuel energy density of 35 megajoules per liter, this translates to a fuel efficiency of approximately 1.75-2.2 kg/J (kilograms per Joule) of energy used to transport cargo by air.
Transporting cargo by sea:
On average, a modern cargo ship consumes about 50-60 kilojoules of energy per metric tonne of cargo per nautical mile traveled (kJ/mt/nm). Assuming a cargo density of around 1,000 kg/m3, this translates to approximately 0.05-0.06 kg/J of energy used to transport cargo by sea.
It’s worth noting that these are just rough estimates, and the actual energy efficiency of transporting cargo by air or sea can vary depending on various factors such as the type of vehicle or vessel used, the cargo load, and the operating conditions.
But should you trust ChatGPT?
Bernie: Yup. There is a reason tea clippers no longer sail the oceans, and won’t again in any numbers. It’s also why we have the Roaring Forties and the Doldrums – wind power has all these annoying drawbacks.
What about subs? ‘Look at Life’ suggested this in 1960: https://www.youtube.com/watch?v=gXpiXuJYGws (for those with ADHD or the attention span of a goldfish, go to 6.40 for the relevant bit….).
I suppose those registered in Cartagena don’t count.
Hortator banging a locally sourced biodegradable vegan drum while
slavesthe unvaccinated pull the oars.Cargo planes don’t get to turn off their jet engines and glide, do they?
You’ve never flown an aircraft have you, Steve? Descend from altitude you trim, reduce throttle to minimum & drop down the glide slope (17:1 for a 747). If you’re coming down above the glide slope, the extra fuel used translates to distance covered. So it makes no odds. On a glide slope descent, you’re using just enough fuel to keep the engines turning in case you need them again. They’re providing no thrust at all. You’re trading gravitational potential for velocity.
As I said, it was pure pendantry ( better now?) Solely about the energy calculation. But it is useful in calculating transport efficiencies. They’re not always what people think they are.
Pigou taxation.
https://en.wikipedia.org/wiki/Pigouvian_tax
Pretty clear that for market efficiency the tax should equal the cost of the externality. If it doesn’t, it’s just a deterrent tax or a revenue source. The problem with so-called Pigou taxes is pricing the externality. Mostly it’s just made up nonsense. With the “climate change” ones, it’s not even clear what the sign should be. So they’re one of the other two.
Not very good at physics are you Steve? Sure, an aircraft produces parasitic drag from displacing the mass of air holds it up. That’s included in the cross sectional area. The energy expended getting it to altitude is recovered as it descends. That’s how a plane comes down. You throttle back & trade altitude for flight distance.
Not sure that counts as the energy being recovered.
You can’t use that energy again. Sure, the descent is pretty much “free”, aside from the idling fuel in case you need engines again as you say later, but it isn’t recovered to help you get altitude if needed.
For that you would need some sort of regenerative system, maybe airflow being used to spin up a magnet to charge a battery to power an electric fan engine? Or used to spin up a flywheel type mass to power a fan engine?
Both of which are heavy and therefore shite for an airplane.
bis
“So airfreight would be more energy economical than seafreight. It’s the practicalities that prevent it.”
This isn’t true as sea freight is more economical (in terms of kg/J) than air freight by at least an order of magnitude (see my earlier comment above). This is due to fundamental energy reasons, not practicalities.
“The energy expended getting it to altitude is recovered as it descends.”
Partially true but not really relevant.
I think you may not be taking account of the energy used to stay in the air when cruising. As Steve said “If it wasn’t for that pesky gravity.”
@ BiS, alas your physics is wrong. Aircraft and deeply submerged submarines are comparable in that form drag and skin friction determine resistance. But ships sail along an interface, so that wave-making consumes a fair bit of their power.
I bring further bad news. Much of this was sorted out in the 19th century by Froude , a graduate of Oxford, and Thomson, of Cambridge.
But should you trust ChatGPT?
No.
Units are wrong, and cargo density is in no way relevant. Assuming the input fuel consumption is correct (a big “IF” but I can’t be arsed to check):
Air Transport: 18 litres per 100 T-Km * 35 MJ/L = 630 MJ/100T-Km, or 6.3 MJ per T-Km.
Sea Transport: 55KJ/T-nm divided by 1.85 Km/nm = 30 KJ/T-Km
Since a MJ = 1000 KJ last time I looked, air transport at 6,300 KJ/T-Km is about 200x the energy cost of sea transport.
BiS – I think you are ignoring the energy requirement from the drag when moving at speeds required to generate lift. Drag increases linearly with the density of the fluid, but as the square of the velocity, and power increases as the cube of velocity. A freighter moves at what, 20 knots? while an airplane moves at 400 knots?
You’re correct, dearieme. I inadvertently used parasitic drag rather than parasitic + lift drag for aircraft. Where subs differ from aircraft. Subs have buoyancy, planes don’t. But you’re right. Working at the interface results in inefficient flows.
I think a lot of this was sorted out by boat builders long before a couple of university tossers put their minds to it.
Minimum drag for an aircraft occurs when lift-induced drag is equal to parasite drag. But that is not at the speed for minimum power requirement which would be a bit higher. Airliners in cruise use quite a lot of their power just staying in the air and the rest overcoming form drag. Interestingly, the lift-induced component of the drag depends on the inverse square of increased speed (1/v^2) and the power required to provide lift with 1/v
This is kind of a specialist subject for me, thanks all for the opportunity to show off.
– if you were building 100,000 ton aircraft you would.
Odd that no one does that then.
Are you saying Cloudbase isn’t real? Oh no!
Welsh government wants to bring in a clean air act that would allow road pricing, the opposition parties (including conservatives) commented that it was overdue and didn’t go far enough, there really is no choice when it comes to this green climate net zero craziness
– Sure, the descent is pretty much “free”, . . . , but it isn’t recovered to help you get altitude if needed.
Unless you engage in air combat whilst transporting coal and cement, when you’ll need to constantly exchange altitude for descent speed and back again.
= Are you saying Cloudbase isn’t real?
It was recently taken over by LGBT+P; they really liked the gay Nazi symbol Gerry Anderson came up with for Spectrum. Sadly, all the Angels are now dykes and trannies.
“Barbara Angel, immediate launch!”
” ‘old on, I’ve just got to shove me’sen back in.”
Odd that no one does that then.
I don’t think there’s anything theoretically to prevent it. Rhoda might know. Wouldn’t look much like an aircraft. More like a lifting body or flying wing for maximum aerodynamic efficiency. But where do you take off & land? And the noise would be incredible. Especially using unducted fans for maximum efficiency. Flatten everything under its flightpath.
Pendantry, Yay!!
Umm.. BiS you’re forgetting that ships float because of Archimedes. That one’s for “free”, at any displacement.
All it has to contend with is drag as it goes through the water, but that’s what modern hull shapes are for.
Planes have to generate their lift through speed. And at the speed they’re moving in the air, even in the stratosphere air becomes as “dense” as water. Good for lift, but they do have to keep up their accelleration to keep that lift..
Someone smarter can work out the energy requirements per 100km at relevant speeds, but Market shows that Ships are more efficient when it comes to taking Lots of Stuff somewhere when time isn’t much of an issue, and Planes when you need Small Amounts of Stuff to get somewhere fast.
Trains are somewhere in between those two.
It’s not a “problem” that can be “solved” on the basis of fuel use. Different parameters, applications, and economical use…
What about the point where aircraft are generating such a small amount of lift as airspeed is low they start to need MORE power just to stay up? That’s really inefficient. Apparently it’s not sensible to fly that slowly close to the ground.
Can’t imagine why….
Hmm… the An-225 is in Guinness with the largest load ever moved at just shy of 254 tons.
A standard 40foot container stashed Chinese Export style would do anywhere between 10 and 30 tons.
So.. Something as hyperspecialised as the An-225 could at best carry between 8.5 and 25 containers.
Which in container shipping is… well.. a rounding error.
There is no way planes can replace ships in efficiency at any realistic calculation, unless you add Time as a cost factor.
Time’s important. I once proved why Apple flew iPhones rather than shipped them. Volumes were large enough for containers. But electronics depreciate at 1% a week (rough idea). So, 30 days shipping time and 2 day air freight – air freight is cheaper.
Oh, and in Trivia: Seems that on average the Big Boy container luggers do about 9000 40foot containers.
That’s wet-finger-in-the-air.. 500-ish An-225’s. No idea in Standard Airbusses, but more, probably much more.
Total numner of An-225’s in the world: 1, now deceased because of the Ukie-Putinski kerfuffle.
Going with the planned A350F cargo plane at 109 tons.. errmm… it’d take all the current planes of all major operators to have the equivalent cargo capacity of a single Big Boy container ship…
Something tells me that that Big Boy doesn’t guzzle the amount of fuel those planes do.
I recall with fun the tagline for the advert for rail from Beijing to London
“faster than a ship, cheaper than a plane”
As I said in the original comment, it’s purely pendantry based on energy expenditure. Nothing real world about it, But was there anything real world about the article prompted the post?