3 ms·

Pumped hydro is 70-80% efficient at storing energy. [1] Converting to sensible units gives mass = 55e3 * 3.79kg/gallon ~ 208450kg height = 221 meters mass *

Pumped hydro is 70-80% efficient at storing energy. [1] Converting to sensible units gives mass = 55e3 * 3.79kg/gallon ~ 208450kg height = 221 meters mass * height * 9.8m/s^2 ~ 452043210 joules (watt-seconds) or 125KwH, 70% of that is 87KwH. What does gasoline have to do with energy storage on the grid? Furthermore, a gallon of gas has 33KwH [2]. What does the Itaipu Dam's installed power have to do with stored energy? [1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... [2] https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

keanzu 7y ago
> What does the Itaipu Dam's installed power have to do with stored energy? Nothing. Was there something to suggest otherwise? I listed two weak points for hydro: Terrible energy density, massive land use. My first reference supported the first point and my second reference addressed the second point. Land use: 1,350 square kilometres were flooded. The installed power was to give context of how big the plant is.
- dredmorbius 7y ago
  Again: the size is incidental to that specific dam. Pumped hydro facilities can be vastly smaller. Ffestiniog Power Station in the UK is on the order of 1 hectare (1/100 km^2) in area (based on 170,000 m^3 storage and a 34m dam height). It's a modest and early pumped-hydro facility. https://en.wikipedia.org/wiki/Ffestiniog_Power_Station https://en.wikipedia.org/wiki/Ffestiniog_Power_Station Bath County Pumped Storage in the US has an upper reservoir of 107 and a lower of 226 hectares respectively, or 1 km^2 and 2 km^2, roughly. It is the largest in the US. https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... There is no reason for a purely pumped-hydro facility to be anywhere remotely near the size of Itaipu. Which is not in fact a pumped hydroelectric storage facility, but a hydroelectric generating station with no pumped-hydro storage capabilities or functions. https://en.wikipedia.org/wiki/Itaipu_Dam https://en.wikipedia.org/wiki/Itaipu_Dam A red herring.
  - keanzu 7y ago
    You are reading words that aren't there. The top level comment this thread started with is: >You couldn't be more Dam wrong. I am talking about dams, not pumped storage.
    - dredmorbius 7y ago
      And that comment responded to "Energy storage isn't really feasible". And was followed up, by the same author, with another post specifically about pumped storage: https://news.ycombinator.com/item?id=21479576 https://news.ycombinator.com/item?id=21479576 That we're still discussing this over 24 hours later may strike someone as amusing, but the jokes gone rather stale. Cheers.

keanzu 7y ago

> What does the Itaipu Dam's installed power have to do with stored energy? Nothing. Was there something to suggest otherwise? I listed two weak points for hydro: Terrible energy density, massive land use. My first reference supported the first point and my second reference addressed the second point. Land use: 1,350 square kilometres were flooded. The installed power was to give context of how big the plant is.

dredmorbius 7y ago
Again: the size is incidental to that specific dam. Pumped hydro facilities can be vastly smaller. Ffestiniog Power Station in the UK is on the order of 1 hectare (1/100 km^2) in area (based on 170,000 m^3 storage and a 34m dam height). It's a modest and early pumped-hydro facility. https://en.wikipedia.org/wiki/Ffestiniog_Power_Station https://en.wikipedia.org/wiki/Ffestiniog_Power_Station Bath County Pumped Storage in the US has an upper reservoir of 107 and a lower of 226 hectares respectively, or 1 km^2 and 2 km^2, roughly. It is the largest in the US. https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... There is no reason for a purely pumped-hydro facility to be anywhere remotely near the size of Itaipu. Which is not in fact a pumped hydroelectric storage facility, but a hydroelectric generating station with no pumped-hydro storage capabilities or functions. https://en.wikipedia.org/wiki/Itaipu_Dam https://en.wikipedia.org/wiki/Itaipu_Dam A red herring.
- keanzu 7y ago
  You are reading words that aren't there. The top level comment this thread started with is: >You couldn't be more Dam wrong. I am talking about dams, not pumped storage.
  - dredmorbius 7y ago
    And that comment responded to "Energy storage isn't really feasible". And was followed up, by the same author, with another post specifically about pumped storage: https://news.ycombinator.com/item?id=21479576 https://news.ycombinator.com/item?id=21479576 That we're still discussing this over 24 hours later may strike someone as amusing, but the jokes gone rather stale. Cheers.