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Originally Posted by AndrewJ
True, but one listener who obviously knew the full process and had thought it through indicated that it does provide an insurance backup, but is very inefficient.
When pushed about it, he mentioned a lot of the "spare/off peak" electricity used to pump the water back up the hill would actually be coming from coal, not renewables, ( as the pumps will be near the snowy system ) and there arent many nearby renewables.
When you factor in all of the transmission/mechanical losses, the carbon footprint per KWhr for the final product goes through the roof.
Be interesting to see what those numbers really are, and if they could affect our emissions targets.
Andrew
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I don't know Andrew, but everything I read suggests that round trip efficiency is maybe as high as an excellent 80%
http://energystorage.org/energy-stor...ectric-storage. The other side of the efficiency equation may possibly be that thermal plants do not have to be operating with excess capacity in place (just in case), if there is pumped hydro to smooth out the load - pumped hydro may thus make operation of even coal powered generators more efficient - but that is just conjecture. must see if there is any info on the effect of pumped hydro on Queensland power generation.
power it from renewables and the carbon footprint is surely going to be small. If you cannot get any renewable energy from the grid, then you are right - it does not make so much sense. I guess that it should only be considered for a future high-renewables grid - maybe that is what the Government is anticipating.