"If you are trying to tell us that the water will back up into...

  1. 79,551 Posts.
    lightbulb Created with Sketch. 75
    "If you are trying to tell us that the water will back up into the generator tail race, reducing the generating head"

    if you read your earliest post on the super pit idea -

    "The last I heard the super pit was about 600 metres deep. What would be wrong with putting a reservoir or two at the ground level above the pit and making the power flowing the water back into the pit?
    500 or so metres would make pretty reasonable power by my calculations and a minimal distance to pump it back up."

    it reads like you are having 500 m of head - that's at first glance - which would mean that the generator to have that much head would have to be at the bottom - which, I said - it can't be - but, it could be taken another way - it could be taken that a generator could be placed downhole say 300 m vertical - (as you said you would have a reservoir or two at the top) - then you would have head of 300 m - but would have to lift the water back up 600 m (if you used the full capacity) - because somewhere you said that you would never have more depth of water than 300 m - which means that if the hole is 600 m deep - then the surface of water would be 300 m below ground min. and 300 m above pit bottom max. - the pump pickup for the recharge you would set at a level where you had your drawdown cycle plus a bit I guess - so, you would only raise the water the minimum you had to (because it sure burns power to lift it any distance).

    All the numbers would have to be run to see where the most viable volume cycle was - including taking into account very much just where you got the excess power from - IF there was any.

    I ask you again - would you build this and expect to make a profit?
 
arrow-down-2 Created with Sketch. arrow-down-2 Created with Sketch.