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0 pointsthworp3y ago0 comments

Not so fast here. From what I've been able to find out (telling that Tesla itself did not release any figures on weights for their semi) the Tesla Semi will weigh about 10 tons (without trailer), which is slightly more than even the most powerful, longest-range long-haul trucks that have ranges of 2000+ miles.

So you have (conservatively) 5 tons less cargo which is a 25% reduction from the typical 20 tons. Then you have (very conservatively) 20% less distance traveled due to needing more frequent recharge stops.

In practice then, you need double the trucks. So yea it is theoretically possible to electrify long-haul trucking, but it's also ruinously expensive. And that's ignoring any considerations for different maintenance.

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AtlasBarfed3y ago

But the tesla truck is basically 1.0.

Lithium-sulfur, Sodium-sulfur, and solid state variants plus a host of other tricks are coming down the pipeline in the next 5-10 years. A conservative estimate is that batteries will be 2x better than the current (the papers indicate 4x but let's see what happens).

The other aspects here:

- BEV semis are cheaper to operate long-term since electricity is cheaper than diesel (even without the carbon tax diesel operation should be paying), most calculations 5 years ago before the current 5-6$/gallon diesel crisis showed that.

- electricity will continue to drop in price as Solar/Wind continue to drop in LCOE over then next ten years

- BEV batteries will continue to drop rapidly in price over the next decade until the initial cost of BEVs will be structurally less than any ICE drivetrain

- highway self-driving, or highway "pack" driving, is going to get a LOT more prevalent. Highway self driving for trucks will likely converge/evolve with infrastructure to enable long haul trucks to self-drive at slower rates (more efficient) overnight and then be operated at "normal" speeds during the day.

So the number of trucks will probably be irrelevant in the long run. The key metric is probably the one that always mattered: how much to move a ton of cargo per mile. BEVs are probably close or will pass in 5 years ICE transport on equipment / fuel / energy costs alone. In ten years batteries will be so cheap that ICE drivetrains will simply not be a sane option except in the most extreme cases (long haul ultra-rural routes, long haul in deep winter, etc).

Maintenance wise, BEVs are simpler, less fluids, etc. They also might be more resilient to breakdowns. If you have a HUGE battery pack and three axles of power delivery (the Tesla design apparently uses the three axels for acceleration and then only one at cruise), then if one of the drive motors fails, you can fallback to another drive motor usually used only for acceleration. You can subdivide the huge battery pack and if part of it goes out, you have enough juice and drive motors to limp to someplace.

And again, long range can probably be boosted with swappable extra power trailers. Recharge rates will be moot because the power trailers are precharged. The power trailer can probably be shaped to increase the semi's rear aerodynamics better, and increase the overall efficiency of the semi as well.

thworpOP3y ago

> [improving battery tech]

This would be nice if it actually happens, but so far the new chemistries still have many unsolved fundamental issues, not to mention safety issues when increasing energy density further.

> [cost per mile / energy costs]

No arguments here, eventually EV running costs per vehicle will be cheaper. But there will probably be surge pricing for charging when renewable output is low. It won't be easy to manage that risk from a business perspective.

> [self-driving]

Sorry to be snarky, but weren't there supposed to be thousands of people's Teslas operating as robo taxis for 5 years now? I'll believe self-driving truck convoys when I see one operating without journalists or politicians watching.

Also, outside of your "power trailers" (see below) running the truck continuously like that would require battery swapping, which is a promising idea but also has a long list of unsolved problems (wear&tear, additional frames and braces required with swapable battery, cost of labour for swapping a truck's battery 4x per day).

> So the number of trucks will probably be irrelevant in the long run.

This left me dumbfounded. Double the traffic, double the CapEx, double the inspections/maintenance doesn't matter at all?

> [range extending trailers]

So your EV truck already lost 5+ tons of cargo space to a battery, now you wanna hitch an extra trailer (another 5~ tons for the frame and 5 tons for another battery. Since the max legal weight is 40 tons your range-extended Semi can now only transport around 10 tons of cargo compared to 25 tons for the most capable diesel trucks.

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