http://www.inference.phy.cam.ac.uk/withouthotair/c15/page_95...
http://www.inference.phy.cam.ac.uk/withouthotair/c20/page_13...
Also according to the US Transportation Energy Book, waterbourne transport more than a order of magnitude more efficient than road freight, and about 50% more efficient than rail.
http://en.wikipedia.org/wiki/Fuel_efficiency_in_transportati...
On the second point. Our cargo rail system is crap. Nowhere in my write-up am I proposing that we unload 100,000 cargo ships per year and load these containers onto diesel trucks or the current train system. That would be incredibly dumb, inefficient, more harmful to the environment and, well, actually impossible.
No, the idea is that a new highly-efficient, all-electric, highly-automated and cargo-only transportation system be built with the express purpose of moving container-based cargo from coast to coast (and port to port) at the highest possible speed and lowest possible power consumption. The idea further suggests that the required energy can come from nuclear, wind and solar power.
The complete elimination of the burning of the most harmful form of fossil fuel from the transportation system is one of the stated goals of the idea.
Furthermore, the idea is also to look 50, 100 or even 200 years into the future. Pollution aside, fossil fuel cost is absolutely, positively guaranteed to increase over the next 200 years. The current system of burning millions of tons of bunker-c fuel per year to bring widgets to Walmart isn't a viable and scalable long-term solution. Not to mention the fact that it is royally fucking up the environment at many levels. I am not a crazy environmentalist by any measure, but this is stupid.
The US freight rail system is the best in the world.[1] We move 10x more than Europe most years on a tons times distance basis. The running gear may look antiquated, but the fundamental numbers are staggering.
"No, the idea is that a new highly-efficient, all-electric, highly-automated and cargo-only transportation system be built with the express purpose of moving container-based cargo from coast to coast (and port to port) at the highest possible speed and lowest possible power consumption."
There is very little demand for raising the speed of freight rail in the US. Speed generally compounds inefficiencies.
Freight handling is by and large already automated and container based in the US rail network.
Existing electric designs preclude the use of double stacked container flat cars, one of the keys of US freight efficiency. Perhaps you have an innovation here?
Building an entirely new high speed electric rail network for freight is an absurd idea. I don't think you've even begun to model the economic realities, particularly the capex of building a new rail network radius'd and graded for high speed, with all above grade crossings.
What I meant is that it could be much, much better. The article you point out hints at some of the issues: The inter-mingling of passenger and cargo trains ends-up seriously affecting the potential performance of cargo trains.
With regards to it being an absurd idea. Well, of course it is! And so is the case for nearly every idea that sparked a revolution in technology and thinking. The earth NOT at the center of the universe? Absurd! The earth not flat? Absurd? Everyone needs a computer on their desk? Absurd!
Not that I am comparing this to any of those shifts in technology. What I am trying to point out is that being open minded enough to even consider the seemingly absurd is an important part of discovering new ideas and developing new technologies. I always consider the absurd. I have hundreds of ideas catalog that are probably absurd. The alternative is to discount everything as ridiculous without even giving it an honest look. I just don't do that.
For example: Could this high speed train take the form of an underground tunnel connecting both coasts? This is absolutely ridiculous and probably even insane to consider. However, I take the approach of at least doing the research to try to get a sense of proportion in terms of cost and technical feasibility. For example, would there be an important mining element to the project that could offset the costs? I don't know and I am not trying to argue for a 3,000 mile tunnel. All I am saying is that I believe that it is very important to give seemingly ridiculous ideas a chance to be explored and, if need be, discarded based on data and not knee-jerk reaction.
This probably deserves a little more attention.
Having done a lot of sailing as well as ocean-fishing on different size vessels I know exactly what you are talking about. What you might be confusing is that at zero speed there's a huge difference between something floating on water and a truck resting on the ground.
In the case of a large boat floating on water, so long as you are not after making it move quickly you are almost just fighting inertia. So, yes, a fifteen year old kid pulling on a rope could make a large boat move.
When it comes to a truck sitting on the ground you have to contend with rolling friction as well as the static friction (because nothing is moving) and the viscous drag of all the mechanical elements, oil and grease in the drivetrain. It could take hundreds of pounds of force to get it to budge. Once your break through static friction then you have a much reduced dynamic friction and viscous drag (oil and grease in the drivetrain) --again, so long as speed is very, very low-- as well as the rolling friction of the tires.
If, on the other hand, that truck was resting on a frozen lake bed and if the tires are not frozen-glued into the ice, and, if the ice is not deformed under the tires, the same fifteen year old kid could move it just as well as he moved the boat. In fact, it might even be easier because there isn't a significant v^3 component to the power required to make it move.
Once you start to add speed to the problem it is easy to see that moving the same object through water will require at least 830 times more water.
At speed the power required to counter drag comes into play.
Power = 1/2 * fluid density * velocity ^3 * coefficient of drag * area
If it takes one horsepower to move something in air at a given speed you'll need over 800 horsepower to achieve the same speed in water. It's the difference between a model airplane engine and a Formula 1 race car engine.
There's a good article in Wikepedia on drag:
http://en.wikipedia.org/wiki/Drag_(physics)
Get down to the "Power" heading. That's the formula you want to look at.
To get back to your yacht vs. truck example. What you would really have to experience is pulling each of them at 20 or 30 miles per hour with a rope (chain?). Of course, it would take super-human strength and endurance to be able to do that.
POWER to overcome drag is proportional to the CUBE of the velocity. This is the main reason container ships have been slowing down from about 30 miles per hour to 20 in direct response to the cost of fuel.
The power to overcome drag is also directly proportional to the density of the fluid.
Air density: 1.2041 kg/m^3
Water density: 1,000.00 kg/m^3 (pure water)
Here's a practical example: Let's move a Toyota Camry through air and water at 20 miles per hour and compare. We'll ignore friction.
http://www.toyota.com/camry/specs.html
Frontal area: 57.9in x 71.7in = 2.68 m^2
Coefficient of drag: 0.28
Power = 1/2 * density * velocity ^ 3 * area * coefficient of drag
Power in air =
1/2 * 1.2041 Kg/m^3 * (8.9 m/s ^ 3) * 2.68 m^2 * 0.28
= 0.43 horsepower
Power in water =
1/2 * 1,000 Kg/m^3 * (8.9 m/s ^ 3) * 2.68 m^2 * 0.28
= 353.02 horsepower
How about now moving up to 40 miles per hour?
Power in air = 3.4 HP
Power in water = 2,824.14
If we moved the Toyota Camry through air at 188 miles per hour we would need nearly exactly the same power required to move the same car through water at 20 miles per hour.
Bottom line, moving anything on water is very expensive if you have to burn fuel to do it. Unless I am missing something very fundamental there simply is no comparison.
Unless it's a submarine, a ship doesn't move through water, it floats on top of it. The wetted surface is going to be a tiny fraction of the total frontal area. 90% or more of the hydrodynamic drag of a ship (by area) is in the air, not in the water.
For example, here is a nice little 21-foot 1200-lb motor boat that can reach 16 knots with a 25 hp motor, while carrying four people: http://www.southportislandmarine.com/ordereze/1011/page.aspx
The nice little boat you are linking to can do what it does largely because at a certain speed it will start to plane. These are very, very different conditions.
Two of the components of drag on a boat are form and parasitic or frictional drag. The first can be thought of as simply the drag created to push water out of the way. Here the shape of the boat is important. The second is the drag created by water "rubbing" against the portion of the hull in contact with it. Think of sandpaper against wood. More wood and more sandpaper means more resistance to motion.
As speed increases both friction and form drag increase with the square of the speed.
On a planing hull --one that can generate lift and get the boat up and partially out of the water-- form drag decreases significantly once you are "on a plane" (off the water) and friction drag increases. As it turns out, each boat has a sweet spot where it operates best. And, of course, as you get on a plane the power required in order to reach or sustain a given speed decreases significantly when compared to a displacement (non-planing) hull.
A Panamax ship carrying 4,400 TEU does not plane. It is, as far as a know, a pure displacement vessel. So, yeah, you need a tremendous amount of power to counteract significant components of both form and parasitic drag.
A Panamax container ship can have up to nearly 400 square meters of cross-sectional area under water. That's about 4,000 square feet. So, while it isn't exactly the same thing, only for the purpose of visualization, imagine a 100 foot long x 40 foot rigid piece of plywood fully submerged in water. Not try to push it forward at 20 miles per hour. Right. That's why they have to burn nearly a million and a half dollars of bunker-C fuel to get from Los Angeles to NYC.
Physics can be really inconvenient sometimes.
1. Assuming the same speeds. Ships go slower than trains (say 40kmph compared to 80kmph). 2. The frontal area is not the same as only part of the ship is underwater. Further, for a long train, the frontal area drag is likely less than the skin friction drag. 3. The coefficient of drag is not the same as the CD of a train is different than for a boat. 4. The amount of cargo on each is not the same, and would need to be normalized for a fair comparison.
I'd be happy to take a quick look at your materials off-line, please send to jd2planks at hotmail
With regards to the rest of your comments, I've done some of those calculations. Again, there is no comparison.
I need to repeat that the idea here is NOT to in ANY WAY use existing truck or cargo rail systems. They just don't perform. Here in the US you are lucky if you can get cargo trains moving on average at 20 to 30 miles per hour. In other words, the move just as slowly as cargo ships, except that they can't pull the same number of containers.
The idea is that a new purpose-built system is the solution.
Also, please keep in mind that the idea here isn't necessarily to search for the most efficient mode of cargo transportation in complete isolation of the realities of where they derive their energy from.
Here's a very interesting paper on the aerodynamics of high-speed trains:
http://ompldr.org/vMXlsOA/Aerodynamics_HSR02.pdf
Anyhow, I sent you all my files via a shared Dropbox folder. I'd be interested in what you have to say once you have a chance to look at it all.
To be sure, there are huge issues with the idea that have absolutely nothing whatsoever to do with science and technology. I could not imagine the problems one might encounter in terms of the various special-interest groups that would get in the way of building such a thing, even if it was so good that it would save the world. I think the phrase "can't get out of our own way to save our lives" rings true in more than one way, at least in the US.
I'd be happy to look at your calculations. My knowledge of hydrodynamics is somewhat limited, but I do have a fairly good understanding of aerodynamics and a lot of that stuff is transferable. I can't decipher your email riddle though - is [4:5] saying the 4th and 5th characters? Mine is leorampen (at) gmail.
The camry example was just an illustration of the power relationship of something moving through water. Nothing more than that.
The comparison of a container ship with 5,000 TEU (2,500 40 foot containers) vs. a train is, of course, different. And, of course, it isn't as simple as looking at cross-sectional area. That would be a gross oversimplification. Sometimes you have to assume that a cow is a uniform sphere of milk just to start to have some numbers to talk about.
Imagine a train design to carry containers at 200 miles per hour. Single file. So, now, the cross sectional area is that of a single container, which is very small. If the train is designed to minimize parasitic drag and all of the frictional components of the rolling system it could be incredibly efficient when compared to a ship pushing some 4000 square feet (400 square meters) of cross sectional area of water at 20 miles per hour.
And, as I have said multiple times, this isn't really solely about pure energy efficiency as much as a forward looking idea to that hopes to deal with the grotesque level of environmental pollution these ships produce as well as what might happen over the next 100 or 200 years with fossil fuels. One really has to start looking in at least a 50 to 100 year time scale to understand that what we are doing today is not sustainable in any way at all. To some extent, arguing the finer points of how much one displaces vs. the other and whether one solution is a few percent more efficient than the other is to miss the point.
I'll go ahead and send you a link to the data.
The only thing that could make land-based transport less efficient (other than fuel and power-plant issues) is rolling and drivetrain losses. I doubt that those make-up for the over 800-to-1 power discrepancy.
The greater point here isn't a pissing match between individual efficiencies but rather to look at the problem with a long (50 to 200 years) perspective in terms of pollution, fossil fuel consumption, geo-political and economic concerns and more.
One interesting article says that one of the mega container ships pollutes more than 50 million cars see:
http://www.guardian.co.uk/environment/2009/apr/09/shipping-p...
The claim is that just 15 of the worlds biggest ships pollute more than all cars in the world combined.
Here's a back-of-the-envelope calculation for moving a 40-foot shipping container over rail from NYC to LA: 3 cents per ton-mile * 30 tons * 2800 miles = ~$2500. I couldn't find a quote for that route by sea, but from NYC to London I got a $1750 quote, and I imagine the costs are comparable.
I believe you that container ships are huge polluters. It sounds, though, that it'd be easier to fix this by taxing those externalities, rather than making two arguments simultaneously: that container ships are bad and that we should build a giant high-speed domestic freight rail network.
Take the numbers above with a huge grain of salt, but here are my sources for them: 3 cents per ton-mile: http://www.kehoe.org/owen/portfolio/truck_vs_rail.pdf a 40' container weighs 29kg loaded: http://hamburg-sud.com/hsdg/en/hsdg/servicesproducts/contain...
One Panamax size ship moves 4,400 TEU (container units). Larger ships can do up to 15,000 TEU. If you even tried to move that many containers using conventional trucks or diesel trains you'd probably create more pollution than the ships, not to mention the overloading of the roads and rail.
One of the reasons for AHSCS having to be a high-speed system is that you need to bring speed into the equation in order to deal with the sheer magnitude of the cargo moving about.
The other reason is that you need to be able to offer something competitive in order for shipping companies to choose to go over land with AHSCS versus through the Canal.
The third reason is both economic and geopolitical in nature. By traversing the American continent quickly (~3,000 miles in a day) the system would become competitive for cargo that goes from, say, Shanghai to London/Europe through the Suez Canal.
If, again, my numbers are correct, it would be cheaper and less risky to send Europe-bound cargo from Shanghai to the US West Coast for transportation across the continent using AHSCS and then by ship to Europe. You'd be able to get the cargo there in about the same time or faster, at a lower cost and with far less pollution because you'd eliminate days of bunker-C burning transportation from the process.
In the process you'd also significantly modify the economics of the petroleum economy in the Arab world and isolate the rest of the world from the perils and political issues surrounding the Suez Canal.
As I said in my note. If something like this makes sense from an ecological and business perspective there ramifications go far, far deeper than the simple idea of moving containers by land on an electric high-speed train. It could be a game changer for the next couple of hundred years.
https://en.wikipedia.org/wiki/Panama_Canal#Third_set_of_lock...
http://www.siteselection.com/issues/2011/nov/eastern-seaboar...
More recent report from Europe comparing different transport modes for CO2 by kg-km traveled. Shipping is reported as most efficient over rail and road. http://www.eea.europa.eu/data-and-maps/indicators/energy-eff...
Direct wind power would seem to beat out most of your proposal for land-based transport, which, even running on renewable energy, would require a double-conversion to electricity and then back to motive force. It certainly beats out nuclear!
If you've not been, I highly recommend a trip to Panama City to checkout the canal - it's simply mind blowing watching a super tanker go through the locks.
Do you have any data on the number of container ships that move through the canal that are simply moving from one US coast to the other?
There's a webcam, but it's not a live stream.
Keep in mind that there's a lot more than container ships that also move across the canal. Tankers being one example.
This is a long story, but I'll try to keep it very short. Anyone interested contact me off-list for far more details and an unfinished paper with some of my research.
A couple of years ago my son and I were watching a documentary on the subject of concrete. It was very interesting. They covered a wide range of topics but one of them really started to trigger my curiosity: The Panama Canal.
I don't know why, but I became very interested in the financial metrics surrounding the canal. How much does it cost to cross it? How long does it take? How many ships cross it per year? Where do they come from? Where do they go?
The more I learned the more the reality of the Canal horrified me. Why?
The bulk of the commercial traffic through the Canal are container ships. And these ships burn something very nasty: Bunker Fuel. This is, by almost any measure, the dirtiest fuel you could burn. it's horrible stuff.
When I started to do the math I started to realize the magnitude of the problem. These ships move at about 20 miles per hour. They could go faster but there's a balance between the high cost of hydrodynamic drag and fuel costs. A trip from Shanghai to Long Beach takes about 18 days and will burn somewhere in the range of 3,600 to 7,200 metric tons of fuel. For those not comfortable visualizing units in the metric system, that's from 7,936,560 to 15,873,120 pounds. Yes, fifteen million pounds of the nastiest crap you could burn is used to bring your iPhones (conjecture) and other stuff from Shanghai to Long Beach.
If my research is correct, the fleet of about 100,000 cargo ships (Yes, 100,000!!!) burns over a million metric tons of bunker fuel PER DAY.
400 million metric tons of bunker fuel per year, which is equivalent to 120 billion gallons.
Can't relate to that number?
Here's an interesting comparison:
To get a better sense of how large this number is we can try to relate it to how many cars one could fill-up with fuel and for how long. 120 billion gallons would provide enough fuel to supply 100,000 cars (assuming a 20 gallon tank) with a full tank of gas every week...for over 1,000 years.
And our fleet of container ships use this in ONE YEAR.The evil, when it comes to pollution and energy dependence, isn't the much-abused light bulb; it's the elephant in the room: Ocean-going cargo ships.
While our mass media chooses to focus its attention on an oil spill (because it is sensational and it serves political purposes), what is really killing our planet slowly is the transportation of iPhones, Blackberries, TV's, blenders, washers, cars, widgets and gadgets on inefficient and highly-polluting ocean-going vessels. Even the latest Gulf spill is insignificant in terms of environmental impact when compared to what 100,000 ships are doing to our environment each and every year.
It is estimated that the fleet of nearly 100,000 cargo ships in the world produces over 20 million tons of Sulfur Oxides (SOx) per year. For comparison, the entire fleet of automobiles in the world (about 800 million cars) produces about 80,000 tons of the same contaminant.
How about the Canal?
A container ship traveling from Los Angeles to NYC through the Canal will burn about 4,500 metric tons of buker-C fuel. This amount of fuel costs approximately US $1.8 million. Canal fees would run somewhere around $300K. The trip from L.A. to NYC through the Canal runs well over two million dollars, without including handling, insurance, crew costs, amortization, maintenance, etc. That's quite a chunk of change, however, when divided by the thousands of containers a ship can move it becomes a few hundred dollars per container.
How many ships go through the Canal per year?
Approximately 15,000.
I'll leave you to do the math. I have far more detail in my notes. What these ships are doing to our environment is simply horrific. The pollution doesn't stop at the act of burning fuel.
Cargo ships are also the source of an unusual form of pollution. Ships use huge ballast tanks to stabilize themselves. These ballast tanks are filled and emptied of sea water during loading and unloading operations at port. It is through this mechanism that cargo ships are responsible for transporting harmful organisms across the world into ecosystems that cannot handle them. The introduction of non-native species into a new ecosystem can have devastating consequences.
And so, from watching a simple documentary I came to the realization that, for some strange reason, we have been ignoring the most significant source of environmental pollution on our planet. And, beyond that, one of the largest --if not the largest-- consumer of petroleum products.
I didn't stop at just identifying the problem. I also wanted to take a stab at a solution. I came up with something I called "The American High Speed Cargo System" (AHSCS) as a loose proposal. This would be a cargo-only, electric powered, high speed rail system. It would connect --at the very least-- both coasts and, ideally, other major US ports. The idea would be to move cargo over land from port to port at 200 miles per hour. High speed passenger trains in the US are a waste of money and that's particularly true in California (don't get me started there). Not so for high-speed cargo.
The numbers are there to support it: A cargo ship spends over two million dollars to get from L.A. to NYC. Probably closer to three. Those same containers could be moved far more efficiently over land, at similar or lower costs and pollute far, far less. You are exchanging aerodynamic drag for hydrodynamic drag. Huge difference.
In terms of energy costs (just the electricity), I came up with numbers in the order of $10K for a trip from L.A. to NYC. I further estimated that the system would require around 700MW of power, let's call it 1,000MW. We have 53 nuclear plants that can source 1GW each. This is a case where nuclear power might be a really good option.
However, the scope of the project needs to be realized. Developing and building such a systems has the potential to generate hundreds of thousands of jobs, if not millions. It should be revenue neutral if not positive (sorry Panama). It would allow for the installation of upgraded communications and power backbones that would be synergistic to the process of building the rail system. It would also allow for the potential to install huge solar and wind-power farms to fully or partially power the system.
I have not explored every angle but would like to think that, if my numbers and assumptions are right, this could be the most important project this nation could embark on. You have to think in terms of a hundred or two-hundred year scale. These ships are not going to go away unless something very significant changes. Of course, the same concept ought to be replicated across the planet. Again, if I am right, we should strive to eliminate most, if not all, container ships traversing our oceans. We are making an absolute mess out of our planet.
http://news.discovery.com/tech/shipping-network-map.html
Like I said, there's more. If interested email me off list and I can send you a copy of my notes so far. It'd be interesting to have someone go over my notes and verify my assumptions and calculations. I tried to raise the issue with politicians but, what can I say, I only have so much time to deal with morons.
NOTE:
I thank you for your comments. I have to ask that you do me a favor. Please refrain from making categorical statements about the relative efficiency of ships vs. a proposed high-speed electric train without having done the math yourself. Please drop me an email and I'll be more than happy to provide you with a copy of my calcs, an unfinished paper as well as links, PDF's and references. Then we can talk about the merits of the concept. I am actually very interested in having the concept, calculations and assumptions criticized. Arguing outside of a common frame of reference is rather difficult.