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Comment by grecy | Hacker News Reader

See also - many mines around the world using enormous electric trucks that never need to be re-charged. They go uphill empty, and re-gen their entire battery on the way down when fully loaded.

https://www.greencarreports.com/news/1124478_world-s-largest...

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I am embarrassed to say how little sense that made to me - the mines with which I am passingly familiar are all open-pit copper mines, where the extraction takes place below the processing, and I could not get my head around the idea that this one truck was taking some material down to the mine.

Of course the answer is that this mine is at the top of a mountain, and the processing facility is lower. The material the truck hauls is lime and marl.

It really is breathtaking - in a heartbreaking way - that we have 'developed' to the point as a society where we regularly destroy entire mountains.

Removing them is not without consequence - a mountain alters the weather around it.

So incredibly foolish.

wait until you find about about Kardashev Type II civilizations

Crazy, basically using the stored potential energy to their advantage.

Never occurred to me to use the energy to create electricity. Makes me wonder if you could build a power plant at the bottom of a mountain that slowly levels the mountain to power the local grid.

I wonder just how much potential energy could be extracted from a mountain?

I've got an idea.. we build a wall at the edge of a huge mountain area. Water collects behind the wall during the winter, and then in the spring and summer we let the water out through a hole in the wall, which spins generators while the water flows out the hole.

Interestingly, there's a lot of current work around grid energy storage. Storing excess wind/solar power for use overnight, etc.

Everybody assumes batteries (lithium etc.) as the way to go. However the greenest / most efficient way to store the energy is actually just pumping water uphill to a reservoir, and extracting the energy by letting it flow back down.

Of course this storage system only works wherever there is someplace "higher" to pump the water. My understanding is that it's not worth the trouble to build a hill/mountain to pump the water up.

An excellent blog post on this idea: https://dothemath.ucsd.edu/2011/11/pump-up-the-storage/

> greenest

What does green mean here? Most of the developed world's easily used hydro sites are already in use. Expanding them in most countries means relocating lots of people, building huge dams, drowning towns, villages, and historical artefacts, losing agricultural land, disturbing river flows and irrigation systems.

Not always very 'green'.

And when you have the space and the ability to build such pumped-storage hydroelectricity facilities, they require much cheaper and much more environment friendly materials.

And most already build hydroelectricity facilities can be retrofitted (although at high cost) to become pumped-storage hydroelectricity facilities.

> And most already build hydroelectricity facilities can be retrofitted (although at high cost) to become pumped-storage hydroelectricity facilities.

Really? You need a huge downstream reservoir to hold the water that you are going to pump to the upstream reservoir.

What prevents you from digging a very deep downstream hole to store such water besides cost?

I think you need a bigger word than digging, it wouldn't be a gang of navvies with shovels. The cost would be enormous, there are better ways to spend the money: solar, wind, better electricity networks, DC interconnects.

500m is plenty 'high'...

https://en.wikipedia.org/wiki/Dinorwig_Power_Station

I don't think "everybody assumes batteries". Pumped hydro has been around for a long time, and anyone with any interest in the subject knows it's cheap and effective.

What about all of those open pit mines? Surely some of them have access to a lower elevation location where the water could be piped. Or, two adjacent pit mines.

I think cutting up the mountain into managable pieces might consume a lot of produced energy.

I wonder what they are doing with the excess power. I'm sure it wouldn't be worth it to pump back to the grid, but maybe to off load into mining equipment, especially since the truck would need to start at around 60% battery charge each day to avoid over charging.

Running other equipment within the mine and lessening the load on the generators, generally.

Seems like a circular problem, how did you get all the cargo at the top of the hill in the first place?

It's a mine. The hill is the cargo.

Mountain forming is how all that cargo got to the top.

they're extracting the cargo from the earth at the top of the hill.

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