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Comment by digestives | Hacker News Reader

Engineering Explained made a good breakdown and analysis video on the physics of the truck:

"Does The Tesla Semi Make Any Sense?" https://www.youtube.com/watch?v=Uv44W7xa4IU

The TL;DR of that great video goes against Betteridge's Law: yes it makes sense ("no fatal flaw found"), with the known information at the time Jason made the video. The charging infrastructure is likely not trivial, though; in the comments it was pointed out the infrastructure likely makes heavy use of batteries to avoid stressing out local substations and avoid abusing grid peaking.

> the infrastructure likely makes heavy use of batteries to avoid stressing out local substations and avoid abusing grid peaking

From Tesla's presentation, it looks like that.

Right, and that throws off calculations I've seen so far on Semi's ROI because I haven't been able to find out what that charging infrastructure costs per truck in a single truck scenario, two truck scenario, five truck scenario, and so on. MWh of batteries and the accompanying high-voltage installs do not come cheap, and there is maintenance and capex replacements associated with all that.

As much as all that costs and as much electricity it gulps down, you might as well arrange with the utility providers to put in the marginal additional equipment to secure a discount for always consuming out of nuclear or similar baseload during low utilization periods, and only rarely charging batteries outside those periods, trying as much as possible to avoid tapping peaking plants' output.

The lifetime TCO calculations for the charging infrastructure for full battery replacement included is going to be interesting to peek into. On a simplistic basis, that TCO plus the electricity costs would be put up against the cost of diesel, Diesel Exhaust Fluid (DEF), Diesel Oxidation Catalyst (DOC) catalytic converter, maintenance on the DEF and DOC subsystems, and so on.

With my investor hat on, I still don't have the numbers I'd like to see to evaluate whether the truck is a slam-dunk ROI on short-haul routes.

Most industrial facilities already have 3-phase 240 or 480 power and tend to be fed by higher capacity feeders than you see in residential areas. They also tend to be closer to high voltage feeders because everyone hates HV lines running through residential areas.

People are way over-estimating how much work will be needed and how difficult it will be. In many cases the utility will either swap out or drop another 3-phase transformer in place with CT-based metering. The customer will run some conduit. The more power you anticipate purchasing from the utility the bigger the discount they'll give you on the work. In some cases the existing medium voltage lines will be at capacity so they'll pull a new one from a substation but they aren't going to charge $1m for it. This isn't exactly rocket science... everyone who builds a new factory goes through the same process. Utilities do this work every single day.

EV truck fleets will be rolled out over time. The grid and charging infrastructure will adapt. Everything will be fine.

An important question for me was how do you defeat massive energy density of desal. This is a great video to answer that. TLDR; Semi will need at least 4 tons of batteries. But this works out because it is still probably around just 10% of weight of the fully loaded truck. It occurs to me that economy degrades if you have to haul big but less heavy loads. Cost wise you still make profit as long as truck is loaded and electricity remains cheap. Overall, this would be good solution for short haul heavy load.

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