6 ms·

Pumped hydro is always brought up, which is bizarre to me because it's highly dependent on your geography, unlike battery storage.

by skc 10y ago

__jal 10y ago
Why is it bizarre? It is a dead-simple, relatively efficient storage mechanism that could potentially coexist with municipal-scale reservoir systems (thus gaining cost efficiencies). Sure, Kansas, US is not the first place one would look to build one. But most of the world is not Kansas. To flip that around, there exist applications where battery storage isn't reasonable. Is it thus also bizarre to bring batteries?
- toomuchtodo 10y ago
  I can drop cargo containers full of Tesla Powerpacks anywhere in the world. I cannot build hydro pumped storage just anywhere.
  - __jal 10y ago
    ...And? You're not answering: > To flip that around, there exist applications where battery storage isn't reasonable. Is it thus also bizarre to bring batteries? The post I was replying to called talking about hydro storage "bizarre". I was pointing out that it isn't. The logic here seems analogous to saying that compact cars suck because you can't use them as a dump truck.
    - toomuchtodo 10y ago
      My argument is that battery storage will slowly become better than all other energy storage methods as the price comes down. Its also helpful that it can be transported and colocated anywhere necessary.
- ghshephard 10y ago
  I'm curious - can you name a scenario in which battery storage isn't reasonable? It seems to me that once we hit the cost/price/weight/density points, they are a solution to pretty much any problem of power storage.
  - yxhuvud 10y ago
    Seasonal imbalances, as stated otherwise in thread. Image you have no sun for a month each year. Good luck building enough batteries to handle that. The strong part of pumped hydropower is that it scales really really well even if the baseline efficiency isn't stellar.
    - maxerickson 10y ago
      This is a roughly 12 hour reservoir: https://www.google.com/maps/@43.9207263,-86.3978435,18314m/data=!3m1!1e3 https://www.google.com/maps/@43.9207263,-86.3978435,18314m/d... It's a big power station, 1.8 GW, but is only providing service to portion of consumers in Michigan. Making it 10 times bigger would probably be doable but it wouldn't be trivial. It's also one of the better places on the planet to build a single reservoir system (otherwise you need 2 enormous reservoirs). I wonder if the answer to seasonal variation will be to make fuel in the summer.
    - xbmcuser 10y ago
      A larger connected world grid could solve some of the problems 10 years or so ago I read some articles of producing solar power in Africa and then using it in Europe.
brashrat 10y ago
Is pumped hydro dependent on geography? I'm no expert and I'm skipping over the research and calculation part, but I'd be somewhat surprised if solar panels on my house could generate enough electricity to pump more water up to a tank on my roof than I could run through for power generation.
- epistasis 10y ago
  It's highly dependent on geography, you need two separate, very large, reservoirs at very different elevations. It takes a lot of water across a big height differential to store electricity. It kind of reminds me of people that think that we should use the exercise bikes in gyms to power the lighting; yes, brilliant, but actually run the numbers and you realize that humans output very very little energy even at peak exercise. The amount of waste on generators would be phenomenal. There are some cases where pumped hydro makes sense, but there's limited scalability.
- astrodust 10y ago
  You can water pump uphill, or, as they're experimenting with here, you can pump air underwater: https://www.torontohydro.com/sites/electricsystem/GridInvestment/powerup/Pages/CompressedAirEnergyStorageProject.aspx https://www.torontohydro.com/sites/electricsystem/GridInvest... I'm sure compressed air in other forms would be a good store. You could also raise and lower weights into a mine, it doesn't matter so long as you can convert between electric energy and kinetic potential of some kind.
- MrsPeaches 10y ago
  Quick calculation: 1000L tank on a roof which is ~4m high. E = m * g * h = 1000 * 9.8 * 4 = ~40,000J Which is about 12Wh not taking into account any losses. You could maybe improve this by having the water fall into a well but still nowhere near what a battery can provide for a fraction of the cost/complexity. A standard 100Ah battery will provide 1200Wh.
- maxerickson 10y ago
  Wikipedia has a nice illustration of the amount of power stored For example, 1000 kilograms of water (1 cubic meter) at the top of a 100 meter tower has a potential energy of about 0.272 kW·h (capable of raising the temperature of the same amount of water by only 0.23 Celsius = 0.42 Fahrenheit). https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... Given the much smaller height of a rooftop tank, every 1000 kg of water pumped would support a number of minutes of normal household usage (a decent refrigerator would need several thousand kg per hour).

Pumped hydro is always brought up, which is bizarre to me because it's highly dependent on your geography, unlike battery storage.

by skc 10y ago

Pumped hydro is always brought up, which is bizarre to me because it's highly dependent on your geography, unlike battery storage.

__jal 10y ago

Why is it bizarre? It is a dead-simple, relatively efficient storage mechanism that could potentially coexist with municipal-scale reservoir systems (thus gaining cost efficiencies). Sure, Kansas, US is not the first place one would look to build one. But most of the world is not Kansas. To flip that around, there exist applications where battery storage isn't reasonable. Is it thus also bizarre to bring batteries?

toomuchtodo 10y ago
I can drop cargo containers full of Tesla Powerpacks anywhere in the world. I cannot build hydro pumped storage just anywhere.
- __jal 10y ago
  ...And? You're not answering: > To flip that around, there exist applications where battery storage isn't reasonable. Is it thus also bizarre to bring batteries? The post I was replying to called talking about hydro storage "bizarre". I was pointing out that it isn't. The logic here seems analogous to saying that compact cars suck because you can't use them as a dump truck.
  - toomuchtodo 10y ago
    My argument is that battery storage will slowly become better than all other energy storage methods as the price comes down. Its also helpful that it can be transported and colocated anywhere necessary.
ghshephard 10y ago
I'm curious - can you name a scenario in which battery storage isn't reasonable? It seems to me that once we hit the cost/price/weight/density points, they are a solution to pretty much any problem of power storage.
- yxhuvud 10y ago
  Seasonal imbalances, as stated otherwise in thread. Image you have no sun for a month each year. Good luck building enough batteries to handle that. The strong part of pumped hydropower is that it scales really really well even if the baseline efficiency isn't stellar.
  - maxerickson 10y ago
    This is a roughly 12 hour reservoir: https://www.google.com/maps/@43.9207263,-86.3978435,18314m/data=!3m1!1e3 https://www.google.com/maps/@43.9207263,-86.3978435,18314m/d... It's a big power station, 1.8 GW, but is only providing service to portion of consumers in Michigan. Making it 10 times bigger would probably be doable but it wouldn't be trivial. It's also one of the better places on the planet to build a single reservoir system (otherwise you need 2 enormous reservoirs). I wonder if the answer to seasonal variation will be to make fuel in the summer.
  - xbmcuser 10y ago
    A larger connected world grid could solve some of the problems 10 years or so ago I read some articles of producing solar power in Africa and then using it in Europe.

brashrat 10y ago

Is pumped hydro dependent on geography? I'm no expert and I'm skipping over the research and calculation part, but I'd be somewhat surprised if solar panels on my house could generate enough electricity to pump more water up to a tank on my roof than I could run through for power generation.

epistasis 10y ago
It's highly dependent on geography, you need two separate, very large, reservoirs at very different elevations. It takes a lot of water across a big height differential to store electricity. It kind of reminds me of people that think that we should use the exercise bikes in gyms to power the lighting; yes, brilliant, but actually run the numbers and you realize that humans output very very little energy even at peak exercise. The amount of waste on generators would be phenomenal. There are some cases where pumped hydro makes sense, but there's limited scalability.
astrodust 10y ago
You can water pump uphill, or, as they're experimenting with here, you can pump air underwater: https://www.torontohydro.com/sites/electricsystem/GridInvestment/powerup/Pages/CompressedAirEnergyStorageProject.aspx https://www.torontohydro.com/sites/electricsystem/GridInvest... I'm sure compressed air in other forms would be a good store. You could also raise and lower weights into a mine, it doesn't matter so long as you can convert between electric energy and kinetic potential of some kind.
MrsPeaches 10y ago
Quick calculation: 1000L tank on a roof which is ~4m high. E = m * g * h = 1000 * 9.8 * 4 = ~40,000J Which is about 12Wh not taking into account any losses. You could maybe improve this by having the water fall into a well but still nowhere near what a battery can provide for a fraction of the cost/complexity. A standard 100Ah battery will provide 1200Wh.
maxerickson 10y ago
Wikipedia has a nice illustration of the amount of power stored For example, 1000 kilograms of water (1 cubic meter) at the top of a 100 meter tower has a potential energy of about 0.272 kW·h (capable of raising the temperature of the same amount of water by only 0.23 Celsius = 0.42 Fahrenheit). https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... Given the much smaller height of a rooftop tank, every 1000 kg of water pumped would support a number of minutes of normal household usage (a decent refrigerator would need several thousand kg per hour).