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0 pointsnerpderp826y ago0 comments

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_hydroelectricit...

[2] https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

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keanzu6y 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.

dredmorbius6y 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

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_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

A red herring.

keanzu6y 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.

1 more reply

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0 pointsnerpderp826y ago0 comments

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_hydroelectricit...

[2] https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

0 comments

keanzu6y 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.

dredmorbius6y 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

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_Sta...

https://en.wikipedia.org/wiki/Itaipu_Dam

A red herring.

keanzu6y 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.

1 more reply

j / k navigate · click thread line to collapse