in a closed pumped system there are more problems than an open non pumped system
it doesn't matter if it's 200 m head or 600 m head --
wherever your generator is - you have to pump water back up -- the full height if your pump is in the bottom -
but, your head diminishes as your water rises when you are taking the power OFF the hydro system.
so - the further into the power cycle you go - the less power you generate - and, when you begin to recover the water using sun or wind or coal or whatever - you always have to raise that water all the way back up
as I said - just because you have a big hole - 500 or 600 deep - to use that depth full potential - it means you have to have a similar volume at the top somewhere
so - the system would 'always' be a power negative - which isn't a bad thing if you had excess power - but, it can never be truly efficient - and, it will always be very very very expensive.
to have it in the boon docks I think is ridiculous ---------- who would pay for it?
the big users would be mining companies of course - but, man, that would be some sort of business arrangement.
And, as if Australia isn't a high cost miner already - you would be up against developing countries that sell diesel at cents per gallon
honestly -- a small system??? possibly - but, to use the actual size of the hole and say a big system??????
na
honestly - if it was an economic goer - Tasmania would have 3 cables running to the mainland and have done it a couple of decades back -
come and have a look at the Forth and Leven rivers - and, see the 'potential' power that just runs into the ocean
