3 ms·

Very naïve question: What are the issues with moving a liquid (water?) from a low storage tank (in say your basement) to a high storage tank (say in your attic

Very naïve question: What are the issues with moving a liquid (water?) from a low storage tank (in say your basement) to a high storage tank (say in your attic) and then at night let it flow in the opposite direction to produce electricity? I haven't done the calculations, but would it require too much liquid or maintenance? I'm also not sure what this would be called? Gravity Battery?

Houshalter 13y ago
converting to and from mechanical energy is inefficient. But it has been done in some places. https://en.wikipedia.org/wiki/List_of_energy_storage_projects#Gravitational_potential_energy_storage https://en.wikipedia.org/wiki/List_of_energy_storage_project...
- jimktrains2 13y ago
  I mean, I figured it was worse than a battery, but if you can store it much more cheaply it might have been worth it? EDIT: The link also goes through some of the pros and cons. Thanks! And cool, my guess at a name wasn't too far off:)
edent 13y ago
Well, back of a fag packet calculation... Let's lift 1KG of water up 5 meters. That will require 50 joules of energy (5 * 9.81). Suppose I want to store 5kWh of energy (half my usage). 1kWh = 3600000J 5kWh = 18000000J 1KG of water is 1 litre. I need to store 360,000 litres of water - that's a bit too much did domestic use :-) Is large here - but I think that's about right.
eckzow 13y ago
I'm also too lazy to actually do the calculation, but to a Fermi approximation XKCD has already more or less proven[1] that it's not terribly practical for a homeowner as an energy storage solution. [1] https://what-if.xkcd.com/91/ https://what-if.xkcd.com/91/
deleted 13y ago
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xxgreg 13y ago
It's called pumped storage. It exists, but only at larger scales than a household system. It's ~80 efficient. http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

Houshalter 13y ago

converting to and from mechanical energy is inefficient. But it has been done in some places. https://en.wikipedia.org/wiki/List_of_energy_storage_projects#Gravitational_potential_energy_storage https://en.wikipedia.org/wiki/List_of_energy_storage_project...

jimktrains2 13y ago
I mean, I figured it was worse than a battery, but if you can store it much more cheaply it might have been worth it? EDIT: The link also goes through some of the pros and cons. Thanks! And cool, my guess at a name wasn't too far off:)

edent 13y ago

Well, back of a fag packet calculation... Let's lift 1KG of water up 5 meters. That will require 50 joules of energy (5 * 9.81). Suppose I want to store 5kWh of energy (half my usage). 1kWh = 3600000J 5kWh = 18000000J 1KG of water is 1 litre. I need to store 360,000 litres of water - that's a bit too much did domestic use :-) Is large here - but I think that's about right.

eckzow 13y ago

I'm also too lazy to actually do the calculation, but to a Fermi approximation XKCD has already more or less proven[1] that it's not terribly practical for a homeowner as an energy storage solution. [1] https://what-if.xkcd.com/91/ https://what-if.xkcd.com/91/

deleted 13y ago

[deleted]

xxgreg 13y ago

It's called pumped storage. It exists, but only at larger scales than a household system. It's ~80 efficient. http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity