[cogman10]

hydro can win if all the stars align. Electrochemical is the real winner though.

This is just a grift. I doubt this thing will ever materialize. It seems like every month a new gravity storage company emerges and none of them go anywhere with their promises.

As I posted elsewhere, my power company is installing 200MWh of storage on 10 acres. It will take them about 6 months to build it out (they've not started construction yet, they project they'll be finished by june. They just finished getting all the approval they need to start work).

That sort of land efficiency and deployment speed won't be matched by any gravity storage system.

Costwise, it'll probably be in the range of $24,000,000 to install (maybe more like 30M with power electronics requirements).

[mcbishop]

> This is just a grift.

I'd like to understand why. Just too much complexity? Gravity storage is compelling to this layman.

[cogman10]

Complexity is a big part of it along with a lot of required materials.

It takes either a lot of heavy weight or a very long decent regardless the storage system in order to store a significant amount of energy. Further, you need some very beefy generators/motors to work with that weight along with some complex equipment to ultimately convert the AC output into what the grid expects.

Look at the proposed (not built system)

https://aresnorthamerica.com/las-vegas-business-press-deal-w...

It requires 20 acres, a mining pit, 30 employees. And how much energy does it store? 12.5 MWh (15 minutes of runtime, 50MW of output). And do notice the date, 2020. From what I can find, this thing hasn't even started operating yet.

That's a VERY expensive battery which hasn't even been built yet.

All of these very special requirements for such a low storage amount is why these things are grifts.

The comparison is my electric company, which is going to install 200MWh of batteries on 10 acres of available land (it's right next to one of their big substations). It'll take them 6 months to do and the main hurdle they had was getting city approval to start work.

The reason pumped hydro is about the only appealing form of a gravity battery is because you can store just massive amounts of water conveniently which gives those systems pretty nice storage levels. Further, the equipment is near the same of any hydro dam. But even those suffer from very specific geography needs before they can get off the ground and massive amounts of hurdles with local regulations in order to even start work. There is, no joke, a proposed pumped hydro system that I know about which has been in the planning stage for the last 20 years as they've been going back and forth with the local county and community.

That's why it's a grift. The competition is chemical battery storage which has stupidly high energy density and almost instant deployment. Any gravity system that is going to be competitive needs both those things before it'd actually be a contender. I've yet to see any of these systems actually get built beyond just tiny prototypes.

[mcbishop]

Thanks for this! ...Thanks for helping me curb my naivete a bit. I think you'd appreciate this effort at even cheaper grid-scale chemical battery storage: https://www.volts.wtf/p/can-second-life-ev-batteries-work