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Comment by SigmundA | Hacker News Reader

Just to put in perspective if my math's right based on 139k btu per gallon and say 40% diesel engine efficiency and 60 gallons per minute truck stop diesel pump flow, the diesel pump is equivalent to about a 60 megawatt charger.

Which is why a diesel semi can refill in a few minutes and go for 1000+ miles while an electric semi will take half hour to charge for 500 miles at 2MW.

Obviously though for mining operations where its short range goes up and then back down electrification is perfect, its also great for urban buses with regular short routes.

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Apparently the largest electric mining trucks on earth never have to charge. They go up the hill empty, load up with tons of rock, and regen all the way back down which is more than enough to recharge. This makes my engineer's heart smile.

Yes that is a beautiful application of regenerative braking I have to say.

Here I was thinking stuff was loaded down in the mine and then driven UP out of the mine.

I realize there are differnt kinds of mines, but assuming it's a hole in the ground, the truck takes the material up, and the hole isn't situated on a hill... why and where is it going down with material? Really interested to read about this.

Probably meant to write a quarry rather than a mine. I think GP was talking about edumper[1]

https://www.autoblog.com/2019/08/26/edumper-electric-mining-...

Ok " drives up a 13-percent incline to pick up the 65 tons of lime and marl it needs to bring to a nearby cement factor"

It was a particular scenario where the quarry was uphill from a factory. Most mines and quarries probably don't have that possibility (They are both holes).

Many quarries are on mountains and this is not an uncommon scenario.

more details about that particular truck: https://hackaday.com/2019/08/22/electric-dump-truck-produces...

> Apparently the largest electric mining trucks on earth never have to charge.

Well that can't be true.

Yes. Yes it can. Regenerative braking downhill, while holding a full load, can generate more power than it takes to move the empty truck back up.

> Well that can't be true.

Think it through a bit more, there isn't any physics being broken here, because the load (i.e. mass) only travels one way.

Those trucks still have to plug in though but to discharge. Regen breaking stops working when the battery is full.

With a big enough hill, you could use the excess energy to smelt the ore on the way down.

The key to sustainability is to organize manufacturing across large height differentials. I’d better open some mines in Denver.

The mines are located at the top of a hill? I tend to think of mines as being down underground. Are we talking about strip mining here?

in that case, top of the hill compared to where to material needs to go, which is at the foot of the mountain.

Similar stuff happens in a ore mine in Sweden with freight trains going downhill to the coast from the mine.

https://www.schaeffler-tomorrow.com/tomorrow/76/index.html

Commercial vehicles are in a position of advantage here. Many of the places they visit are industrial in nature and those will already have large power hookups. Using the loading/unloading time to charge would seem to be an obvious thing to do.

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