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.
Ramin_HAL9001@lemmy.ml 9 months ago
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: 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 it moved over time?
But anyway this is the only example of a viable gravity stored energy system that I know of that is not pumped hydro.
holycrap@lemm.ee 9 months ago
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 9 months ago
Cool, I hadn’t thought of that. Thanks!
Ross_audio@lemmy.world 9 months ago
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.
egonallanon@lemm.ee 9 months ago
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.
hallettj@beehaw.org 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.