Tesla is aiming to K.O. Freightliner

Tesla has pretty clearly relegated the Tesla Semi Truck to a back-burner project. There's no reason for Freightliner or Peterbilt or any other leading semi tractor manufacturer to be worried about the short term market; that is, their business over the next 5 years.

Taking the long view, of course it's inevitable that BEV trucks will replace diesel trucks. But that could take a long time; perhaps as much as 20 years. I hope it will happen sooner, but I wouldn't be surprised if it takes that long for sales of new heavy diesel trucks to dwindle to 10% or less of the market.

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I'm thinking the cross country trucks will be a high margin vehicle. They will be cheaper to operate than the honorable competition leading to higher income for the owner-operators. BUT they need the truck chargers which Musk understands.

Bob Wilson

 

Traditionally, tractors service the trailers for their running needs, e.g. air for
brakes and lighting power. An obvious switch-up would be to have batteries
in the trailers, presumably slung under the floor, which could supply a bulk
of the rig's motive energy for a given run. Fleets that operate in a "drop and
hook" fashion could assign a fresh load along with a charged *big* battery
to a driver, and trailers could get recharged while sitting at docks or around
the yard. In many scenarios drivers wouldn't have to wait around for their
own cabs to charge, although each one would also need its own pack to
move on its own and/or run bobtail when needed. Electrical hookups shouldn't
be hard to standardize, just like "gladhands" are now.

Viewed as a system, BEV truck fleets are entirely doable for many operational
contexts. It locally solves the problem of who owns the effectively "swappable
packs" -- the shipping comany! Unlike the management fails of Better Place,
Tesla swap stations, etc. Trailers are already pretty universal.

_H*

 

The logistics of needing "Megachargers" to charge up the Tesla Semi Trucks at the end of a driving shift will limit their use to two cases:

1. Local deliveries, where the truck will be returned to a fleet parking lot at the end of the shift. Supermarkets do use semi trucks for daily deliveries, so there is an economic use case there.

2. Fleet depot yards along the fleet's regular travel corridors, where the cost/benefit analysis for the fleet operator shows it's worthwhile to pay for installation of Megachargers.

I've seen suggestions that Megachargers could be installed at a customer's loading dock so the truck could recharge while offloading, but I seriously question that would be cost-effective in most cases. It might well make sense to install them at the fleet operator's own warehouses, to charge while the truck is being loaded. But installing one at a customer's loading dock would require the customer to agree to the installation, and furthermore the customer would have to provide the electricity to the charger. It also means the BEV semi tractor could only use that particular loading dock, and if there are several docks, I doubt the customer would want to agree to that limitation.

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Just wondering how the weight of a battery pack compares in range to a tank full of diesel fuel weighing the same? Let's say you have a giant battery pack (will be needed for these semis) that weighs 10K pounds and a tank of fuel that weighs the same. I'm sure the diesel will go further, but the question is how much? What is the ratio?

My next question then would be about trains. You can guess what that would be...

 

https://www.smart-trucking.com/weight-of-diesel-fuel/

Long haul semi trucks usually have dual 100 gallon tanks, sometimes up to 150 i.e. a max of about 300 gallons, which is about 2100 pounds. So the diesel is definitely lighter than a battery pack and as the truck travels, the weight reduces.

As far as I know locomotives with self contained battery packs are used on short hauls and for specialized purposes (mines, in freight yards etc.) On heavily traveled routes, overhead electrification or third rails (or some variant) are used. Power is delivered from the grid and regenerative braking puts power back to the grid, so the size of battery pack on the locomotive is minimal.

I just found that there are some electrified tracks in Chicago, not including the metros that use electrification. But long hauls are usually diesel in the US.

Outside the US the story is different. Heavily traveled routes (passenger and freight) are usually electric powered and it requires a big upfront investment but worth the cost.
https://en.wikipedia.org/wiki/Railway_electrification_system

In 2006, 240,000 km (150,000 mi) (25% by length) of the world rail network was electrified and 50% of all rail transport was carried by electric traction.

In 2012 for electrified kilometers, China surpassed Russia making it first place in the world with over 48,000 km (30,000 mi) electrified.[28] Trailing behind China were Russia 43,300 km (26,900 mi), India 35,488 km (22,051 mi),[29] Germany 21,000 km (13,000 mi), Japan 17,000 km (11,000 mi), and France 15,200 km (9,400 mi).

 

Yes, but the EV motor is significantly lighter than a semi tractor's diesel engine plus transmission. It still doesn't balance out, but the BEV semi tractor is only a few hundred pounds heavier, and over 90% of semi tractor-trailer loads are limited by the space available in the trailer, not weight.

The use case for a BEV semi truck, with current EV tech, is certainly more restrictive than the use case for a diesel semi truck. But that's almost always the case with the new tech in a disruptive tech revolution. The new tech doesn't need to replace all the uses for the old tech all at once; there just needs to be enough usefulness to replace some of the old tech, enough for the new tech to get a foothold in the market. The usefulness of the new tech then expands over time, as it's developed and improved, to displace all or nearly all of the old tech.



In my opinion, the "low quality use" case for BEV semi tractors would be using them for yard mules or portal trucks; several companies are already making them to serve that purpose. That bar has already been passed. Using them for local deliveries, with loads limited by space rather than weight, would be moving up to "medium quality use"; and the "most demanding use" would be long-distance trucking hauling maximum weight loads.

Again, all just my opinion.

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Diesel-electric locomotives, the standard in the United States and many other countries, have no battery pack at all; just a starter battery. All the power comes from the onboard diesel engine, which powers a generator which directly powers the locomotive's traction motors.

Some countries do have mostly or fully electrified railways. For example, Russia's Trans-Siberian Railway is now fully electrified, hauling a great deal of freight in addition to passenger service. But if such EV locomotives have any battery pack at all, it's only a tiny one, and isn't meant to do more than propel the train for a very few minutes beyond where tracks, or overhead lines, are electrified.

Even for small "switcher" locomotives, used for assembling trains in train yards, most are diesel-electric. Wikipedia says "The vast majority of modern switchers are diesels, but countries with near-total electrification, like Switzerland, use electric switchers." However, the accompanying photo shows the switcher powered by overhead electric lines with a catenary power pickup. So again, that's not a BEV locomotive.

Similarly, there are a lot of light rail trains and subway trains which are fully electrified, using direct electric power picked up from a third rail or overhead power lines, and again using little or no battery power.

But of course, there are some exceptions. Quoting from Wikipedia's "Electric locomotive" article:

Battery locomotive

A battery-electric locomotive (or battery locomotive) is powered by on-board batteries; a kind of battery electric vehicle.

Such locomotives are used where a diesel or conventional electric locomotive would be unsuitable. An example is maintenance trains on electrified lines when the electricity supply is turned off. Another use for battery locomotives is in industrial facilities (e.g. refineries or chemical factories) where a combustion-powered locomotive (i.e., steam- or diesel-powered) could cause a safety issue due to the risks of fire, explosion or fumes in a confined space. Battery locomotives are preferred for mines where gas could be ignited by trolley-powered units arcing at the collection shoes, or where electrical resistance could develop in the supply or return circuits, especially at rail joints, and allow dangerous current leakage into the ground. Mine railways often use battery locomotives.
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Yeah, I get that. But what is the comparison or ratio?

 

Back of envelope:

• diesel refueling weight, ~1050 lbs = 2100 / 2, assumes full tank to empty
• BEV refueling weight, 0 lbs

So over time comparing the refueling weights of diesel to BEV:

• 1st -> 1050 lbs vs 0 lbs
• 2nd -> 2100 lbs vs 0 lbs
• 3d -> 3150 lbs vs 0 lbs
• 10th -> 10,500 lbs vs 0 lbs
• 100th -> 105,000 lbs vs 0 lbs

Refueling a diesel adds weight to the truck, every time. In contrast, the BEV weight does not measurably (*) change with each charge.

Bob Wilson

* - E=m*(c**2) can calculate the mass from charging. This becomes m=E/(c**2) and c is 300,000,000 m/sec. So recharging a battery increases the weight by ~1/(900,000,000,000,000) which is a very, very small number.

 

Or, looking at the comparison from the other direction:

The diesel semi gets lighter as it travels and uses up fuel, so for a long trip (using Bob's figures) it may be as much as 1000 lbs lighter at the end than at the start. In such a case, the average weight would be 500 lbs less than the full weight, representing a measurable improvement in energy efficiency.

Contrariwise, the BEV has to haul around the full weight of the battery pack at all times, no matter how much or how little it's charged up.

I have to say, like it or not, the advantage is to the diesel semi here.

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Still not getting any answers to my questions. Of course I know that a battery weight is constant, whether empty or full vs fuel weight. My question is about range per weight, battery vs diesel.

I can do my own calcs using my own car battery weight vs same car in ICE version using weight of the number of gals required to go same range as full electric charge. But thought there was some kind of industry/scientifically accepted measure of the current state of energy stored in a battery compared to diesel fuel or gasoline.

 

None that I have seen published. And here is one reason. What is the use case? Are we talking about a long haul (Los Angles to say Houston, or a short haul say Tuscon to say Phoenix about 100 miles). A diesel truck can do both without needing to change configuration. I would assume that for now a EV truck for a long haul will be a little different than one designed for short hauls, just due to the amount of battery capacity needed.

I think Elon has recognized it and put the Semi on the back burner and will come back to it when he thinks its appropriate. Meanwhile it does no harm to keep slideware out there.

 

I use the EPA metrics in fueleconomy.gov as many of the earlier studies, any before 2016, are sadly out of date. One gallon of gas has ~33 kW of energy but typical ICE engines use only 1/3D to move the car.

Bob Wilson

 

Again, my ratio question is about weight and range. I know gas weighs roughly 6 lbs per gallon, so how many lbs of battery do you need to get the same energy as 1 gal of gas. To put it in semi level comparison, how many lbs of battery do you need to equal the range of 5,000 lbs of diesel fuel (which is a little heavier than gasoline)?

 

No, let's exclude all the factors of drag and weight. Surely the engineers must have tested this and know the answer.

All you need is a dyno that can accurately measure torque. Apply the same torque to an ICE engine and an EV engine and see how much battery charge and fuel is used up in the same time period.

 

Does someone out there know the answer? Yes, I am sure there is. I have not found it in a search, does not mean it does not exist.

 

Well, it seems to me this would be critical data to determine the feasibility of EV semis and trains. I would like to believe that EV propulsion makes even more sense with larger vehicles, esp if you can just change out batteries (like a rail car or two) at station stops along the way. Unless that ratio is so large that at some point it costs more to pull the load than it generates energy.

 

I love the line of questioning and I totally get it. Here’s a clue...and I don’t know the answer and this clue doesn’t provide an answer. But it’s a clue...

My Honda Clarity PHEV can travel about 44 miles on 6 lbs if gasoline. Yet it need hundred and hundreds of pounds of battery fully charged to travel those same 44 miles...
How many hundreds? I don’t know. 5? 7? Somewhere in that range maybe?

So if I’m anywhere close to correct it takes 500 to 700 lbs of today’s lithium battery cells to do the same amount of work as burning 6 lbs of gasoline. presumably this is the type of ratio you’re trying to find?

And this very reason makes me extremely skeptical of how these Tesla trucks will work, hauling extremely heavy loads and pushing a ton of air resistance. Maybe the giant trailers he was hauling in his 2017 demo were 50% battery and can only hold half the volume of cargo of a normal empty semi trailer? I have no idea...

Again I know NOTHING about the subject before anyone jumps down my throat. I simply find this ratio question to be very very interesting...