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Comment by Loic | Hacker News Reader

For the calculations:

A semi (33T, 25T of load) is consuming 35l/100km.

In the given calculations, it is consuming 47l/100km (35% more than the reality).

The efficiency of the truck is given as 2kWh/mile, which means 125kWh/100km.

A Tesla S requires 25,8kWh/100km. Basically, moving 33T takes just 5 times more energy than moving a Tesla S. For the "Diesel" case, this is more 7 times, but maybe the power scaling of electrical propulsion is better (and a better wind efficiency of this truck).

The last point is that the rate of 0.07ct/kWh is maybe too low, you want high power voltage to load your semi, this costs more than normal power.

Well done EVs will be cheaper, but these calculations feel a bit too biased into making the Tesla semi unbeatable.

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I agree, there's no reason to think large haul electric trucks will have a better efficiency margin over internal combustion variants than in the case of passenger vehicles. On the contrary, there's reasons to doubt it, for example large diesel engines are highly optimized for efficiency unlike small consumer cars they are bought by businesses which think in TCO.

So probably the real margin over diesel is about 50% cheaper in fueling. But you have to take into account route restrictions due to limited range, time lost charging etc. Not to say it won't find its place in the market, but the margin and advantages of electrics are not yet so clear cut, it will take decades to reach dominance.

You are only taking into account the negatives and ignore the positives. Electric trucks will have cheaper maintenance. TCO is much better in pretty much all electric vehicle and every study looking at vans in cities has shown this. Semis will most likely show the same thing.

Such semis will also be faster exhilarating and more maneuverable and be a much more pleasant vehicle to drive. All those things are worth something as well.

Of course they will not dominate from day 1 simply because can't produce enough but they will eat away at ICE market share every year for a long time.

By the time they can produce enough of them to take on long haul routes, batteries will be 2-3 generation further along and the economics will tell.

Also the maintenance TCO at scale. A large fleet operator has a staff of experienced diesel mechanics. Is Tesla planning on making a profit on servicing battery packs for these things?

Battery packs are not designed to be serviced, I would imagine that a Semi has like 4-6 packs and each one has to be fully replaced. The same thing goes for the engine, you just remove the whole engine assembly and put in a new one if one breaks.

> you want high power voltage to load your semi, this costs more than normal power

Does it cost more when you're buying huge amounts? If there's a difference I'd expect that to be cheaper since the power company doesn't have to transform it down.

Correct eventually.

But in today's world there are plenty of companies wanting to charge you a 50x markup on power electronics for a truck charge station just because they're novel. Charge stations will end up costing more than the truck (per charge bay) to begin with.

Oh I'm not worried about charge stations, I'm asking about the big fat electrical supply.

It costs more, because you need a bigger bursty supply behind, bigger hardware, etc. You have "some" economy of scale but not fully. This is why for example, you have many charging stations who are now coupled with batteries, to be able to smooth the load on the grid. At the end you get:

grid -> battery pack at the charging station -> battery of the vehicule

Costs more than what?

I thought we were comparing a big bursty supply at 120 volts and a big bursty supply at higher voltage.

Did I understand your initial comment wrong and you weren't talking about voltage at all?

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