this post was submitted on 17 Jan 2024
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Gravity Storage 101 Or Why Pumped Hydro Is The Only Remotely Real Gravity Storage (cleantechnica.com)
submitted 9 months ago by silence7@slrpnk.net to c/energy@slrpnk.net
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[–] Ramin_HAL9001@lemmy.ml 22 points 9 months ago* (last edited 9 months ago) (3 children)

There is only one other gravity storage system that I know of that isn't hydro, but it isn't really a storage system. It is the Forterra ropeway used by a quarry in the UK where buckets of minerals are sent down a rope line similar to a ski lift. Since the quarry is uphill from the processing area, the energy from the material traveling along the rope is used to pull up all the empty buckets. Tom Scott did a YouTube video on it: https://www.youtube.com/watch?v=6RiYXI1Tfu4

I don't know why they didn't just put the mineral processing area closer to the quarry, maybe the quarry moved over time?

But anyway this is the only example of a viable gravity powered energy system that I know of that is not pumped hydro.

[–] holycrap@lemm.ee 13 points 9 months ago (1 children)

Here's a dump truck at a mine that charges the battery via regenerative braking when hauling the material down the hill then uses that energy to drive the empty truck back to the top for the next load. Same idea.

[–] Ramin_HAL9001@lemmy.ml 2 points 9 months ago

Cool, I hadn't thought of that. Thanks!

[–] Ross_audio@lemmy.world 7 points 9 months ago* (last edited 9 months ago) (1 children)

Interestingly we've been through this energy storage journey with clocks before.

You can see old clocks which are gravity powered instead of energy stored in a spring.

Basically we've already learnt that unless we're using hydro, a massive amount of springs may be more useful than gravity. Especially given the space requirements of gravity powered systems

So springs?

What do clocks end up using today? Batteries.

Some with built in solar to charge their battery.

Battery storage is going to win out everywhere the environment isn't already ideal for a gravity system.

Even then you'll probably be able to store more power in a mountain by filling it with batteries than using pumped storage pretty soon.

[–] egonallanon@lemm.ee 3 points 9 months ago (1 children)

There are places and use cases where batteries aren't a great idea for energy storage and there are environmental concerns. I'm interested to see how mechanical flywheels progress for energy storage as while they lack the density and have higher upfront costs they have much lower maintenance costs and longer serve life.

[–] Ross_audio@lemmy.world 4 points 9 months ago (1 children)

Fly wheels are interesting.

Especially as the turbines we currently put steam through are essentially flywheels holding momentum for a short time after shutdown.

A flywheel that can turn for hours would be what's needed. Whether lots of small ones like this:

https://m.youtube.com/watch?v=_STnL0U9PyQ

Or a massive one.

Williams F1 even used a flywheel KERS system at one point. Batteries won there eventually too but if it can be genuinely useful in an F1 car it's certainly possible they could be useful when weight isn't a problem.

[–] egonallanon@lemm.ee 1 points 9 months ago (1 children)

Did Williams ever actually race the flywheel kers? I know it got used in WEC and some road applications.

[–] Ross_audio@lemmy.world 3 points 9 months ago

I don't think they raced it in the end. They sold it to Audi for endurance racing as you say.

Additional weight for occasional extra power wasn't worth it in the end.

[–] hallettj@beehaw.org 5 points 9 months ago

That's pretty neat! But it seems to me it's not storage because they're not putting energy in to get out later. It's more like mining naturally-occurring potential energy from the Earth's crust. Probably that potential energy formed millions of years ago when tectonic plate activity pushed the rock up to its present elevation. So - it's geothermal energy with extra steps.

[–] perestroika@slrpnk.net 9 points 9 months ago

Yep. As for why:

  • the material being raised and lowered must be very cheap (to be able to afford much of it)
  • the material must be possible to automatically handle in arbitrary amounts
  • the friction of raising / lowering the material must be low
  • the handling should not require a slope of particular grade or a specific height

Trains fail the cheapness and arbitrary amount check, along with the slope grade check. Sand fails the friction check. Concrete blocks are close to failing the cheapness and arbitrary amount check. Cranes fail the specific height check for certain ranges of height.

Water... it also requires a certain slope grade, but the range is not narrow.

[–] RubberElectrons@lemmy.world 7 points 9 months ago

Sigh. I'm going to double check this when less tired, but the metrics sound about right.