3 ms·

Is this not just pumped hydro but worse?

by saagarjha 10mo ago

dhampi 10mo ago
Presumably a lot less expensive than pumped hydro to build.
- thereisnospork 10mo ago
  Pretty much zero chance of that. The complexity (moving parts, machined parts, number of generators, number of electrical interconnects (etc.) is so much higher per kilogram basis compared to pumped hydro. Much of the country does half of pumped hydro (storing potential energy in water towers) and delivers it to your door for fractions of a penny per kg, a price that includes a complete distribution network and sourcing/purification of the water.
  - napkinartist 10mo ago
    You have to dredge pumped hydro though. Silt accumulation is a challenging engineering problem and erases capacity over time.
  - nerdsniper 10mo ago
    My understanding is that water towers mostly exist as something to “pump against”, rather than being a vessel that gets filled and emptied repeatedly like a battery would. It does vary in level a bit, often with a circadian rhythm (but also randomly pulsatile). I just don’t think it’s a significant portion of the total water flow that its pressure supports.
mcbishop 10mo ago
I'd love to see an unbiased financial-analysis comparison: this vs. hydro vs. electrochemical.
- cogman10 10mo ago
  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 10mo ago
    > This is just a grift. I'd like to understand why. Just too much complexity? Gravity storage is compelling to this layman.
    - cogman10 10mo ago
      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-watch-ares-nevada-builds-energy-storage-facility-in-pahrump/ 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.
8bitsrule 10mo ago
Water storage is great, the cat's meow ... in places where water is plentiful. But there are HUGE tracts of land in the world where there isn't any water. But people still need the energy, when the winds are calm and the skies are cloudy. Only other kinds of gravity batteries will do, so they're a necessity, especially near remote wind-farms. "Energy Vault’s gravity-based solutions are based on the well-understood physics and mechanical engineering fundamentals of pumped hydroelectric energy storage, but replace water with custom-made composite blocks that can be made from low-cost and locally sourced materials, including local soil, mine tailings, coal combustion residuals (coal ash), and end-of-life decommissioned wind turbine blades." "The 100 MWh gravity-based EVx system is being built adjacent to a wind farm and national grid site in Rudong, Jiangsu Province located outside of Shanghai to augment and balance China’s national energy grid...." https://www.businesswire.com/news/home/20220505005467/en/Energy-Vault-Atlas-Renewable-and-China-Tianying-Begin-Construction-of-First-Chinese-Deployment-of-EVx-Gravity-Based-Energy-Storage-System https://www.businesswire.com/news/home/20220505005467/en/Ene... "China's $1bn bet on gravity to store massive amounts of green energy " https://www.rechargenews.com/energy-transition/chinas-1bn-bet-on-gravity-to-store-massive-amounts-of-green-energy/2-1-1550122?zephr_sso_ott=4oYrjH https://www.rechargenews.com/energy-transition/chinas-1bn-be...
- Veserv 10mo ago
  That is utterly nonsensical. Are there HUGE tracts of land where 100 ton railcars or concrete blocks grow on trees? If not, then how are you getting them there? On a per-mass basis what do you think is easier to transport, railcars or water? Transporting adequate amounts of gravity storage medium is not at all a competitive advantage for non-hydro gravity storage. For that matter, it does not even constitute a meaningful factor except as a disqualifying one for the nonsensical ideas people somehow seem to get funded.
  - Kichererbsen 10mo ago
    I'm not totally sold on the idea itself, but... you don't need to get a 100 ton railcar there. Ship empty railcars and fill it with rocks / sand / water or whatever you find at the destination.
NedF 10mo ago
[dead]

Is this not just pumped hydro but worse?

dhampi 10mo ago

Presumably a lot less expensive than pumped hydro to build.

thereisnospork 10mo ago
Pretty much zero chance of that. The complexity (moving parts, machined parts, number of generators, number of electrical interconnects (etc.) is so much higher per kilogram basis compared to pumped hydro. Much of the country does half of pumped hydro (storing potential energy in water towers) and delivers it to your door for fractions of a penny per kg, a price that includes a complete distribution network and sourcing/purification of the water.
- napkinartist 10mo ago
  You have to dredge pumped hydro though. Silt accumulation is a challenging engineering problem and erases capacity over time.
- nerdsniper 10mo ago
  My understanding is that water towers mostly exist as something to “pump against”, rather than being a vessel that gets filled and emptied repeatedly like a battery would. It does vary in level a bit, often with a circadian rhythm (but also randomly pulsatile). I just don’t think it’s a significant portion of the total water flow that its pressure supports.

mcbishop 10mo ago

I'd love to see an unbiased financial-analysis comparison: this vs. hydro vs. electrochemical.

cogman10 10mo ago
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 10mo ago
  > This is just a grift. I'd like to understand why. Just too much complexity? Gravity storage is compelling to this layman.
  - cogman10 10mo ago
    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-watch-ares-nevada-builds-energy-storage-facility-in-pahrump/ 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.

8bitsrule 10mo ago

Water storage is great, the cat's meow ... in places where water is plentiful. But there are HUGE tracts of land in the world where there isn't any water. But people still need the energy, when the winds are calm and the skies are cloudy. Only other kinds of gravity batteries will do, so they're a necessity, especially near remote wind-farms. "Energy Vault’s gravity-based solutions are based on the well-understood physics and mechanical engineering fundamentals of pumped hydroelectric energy storage, but replace water with custom-made composite blocks that can be made from low-cost and locally sourced materials, including local soil, mine tailings, coal combustion residuals (coal ash), and end-of-life decommissioned wind turbine blades." "The 100 MWh gravity-based EVx system is being built adjacent to a wind farm and national grid site in Rudong, Jiangsu Province located outside of Shanghai to augment and balance China’s national energy grid...." https://www.businesswire.com/news/home/20220505005467/en/Energy-Vault-Atlas-Renewable-and-China-Tianying-Begin-Construction-of-First-Chinese-Deployment-of-EVx-Gravity-Based-Energy-Storage-System https://www.businesswire.com/news/home/20220505005467/en/Ene... "China's $1bn bet on gravity to store massive amounts of green energy " https://www.rechargenews.com/energy-transition/chinas-1bn-bet-on-gravity-to-store-massive-amounts-of-green-energy/2-1-1550122?zephr_sso_ott=4oYrjH https://www.rechargenews.com/energy-transition/chinas-1bn-be...

Veserv 10mo ago
That is utterly nonsensical. Are there HUGE tracts of land where 100 ton railcars or concrete blocks grow on trees? If not, then how are you getting them there? On a per-mass basis what do you think is easier to transport, railcars or water? Transporting adequate amounts of gravity storage medium is not at all a competitive advantage for non-hydro gravity storage. For that matter, it does not even constitute a meaningful factor except as a disqualifying one for the nonsensical ideas people somehow seem to get funded.
- Kichererbsen 10mo ago
  I'm not totally sold on the idea itself, but... you don't need to get a 100 ton railcar there. Ship empty railcars and fill it with rocks / sand / water or whatever you find at the destination.

NedF 10mo ago

[dead]