Thread: Water, Water..It's not everywhere.

Originally Posted by RossM

We are not talking PHES at that scale, we only require short term off river storage systems. A 200MW project requires about 2 GigaLitres of water. Just before xmas the Qld government started to truck about 2 MegaLitres of water per day to a drought affected dam. Based on their costs it would be around $50M to provide the needed water for a 200MW facility. However this is really moot and I apologise; I probably should not have mentioned trucking above, as it really is a distraction. There are so many potential sites and we need so few to secure the required energy that we can afford to select sites with good local water availability.

Ross
I take your caution about mentioning trucking water at commercial rates, but feel I must comment on your contention that we -- in Australia -- only require short term energy storage.

A study from a few years ago -- which I can't currently find to link to -- estimated a worst case scenario where Australia needed something like 3 days of water battery backup energy generation. That quantity of storage would allow Australia to become 100% carbon free -- discounting the carbon released by dams, solar and wind -- and provide something like 1 in 10,000 reliability (but it may have only been 1 in 1000).
(For comparison, dam safety is assessed as a 1 in 15,000 risk -- and some people find that risk of failure too high.)

In 2016/17 Australia's electricity production was 258 TeraWatt hours (258 x 10^12 Wh) -- 3 days electricity consumption is roughly 2 TWh.
Even if you are prepared to accept a higher risk of power disruption, even 1 TWh of energy storage is still a very very large number.

So even if 1,000 of the 22,000 potential pumped hydro sites are viable, at 200 MW per site -- each site needs to run for something like 5 hours to supply a total of 1 TWh. At 2 Gl of water per site, that's something like 3,300 times the volume of Lake Eucumbene (when it's full). A hugh volume of water.


If the Australian grid is to become self-sustaining and stable, we can not kid ourselves on the scale of the generation "problem". When the lights go out, it's too late to say "I should have ..."

Originally Posted by ian

Ross
I take your caution about mentioning trucking water at commercial rates, but feel I must comment on your contention that we -- in Australia -- only require short term energy storage.

A study from a few years ago -- which I can't currently find to link to -- estimated a worst case scenario where Australia needed something like 3 days of water battery backup energy generation. That quantity of storage would allow Australia to become 100% carbon free -- discounting the carbon released by dams, solar and wind -- and provide something like 1 in 10,000 reliability (but it may have only been 1 in 1000).
(For comparison, dam safety is assessed as a 1 in 15,000 risk -- and some people find that risk of failure too high.)

In 2016/17 Australia's electricity production was 258 TeraWatt hours (258 x 10^12 Wh) -- 3 days electricity consumption is roughly 2 TWh.
Even if you are prepared to accept a higher risk of power disruption, even 1 TWh of energy storage is still a very very large number.

So even if 1,000 of the 22,000 potential pumped hydro sites are viable, at 200 MW per site -- each site needs to run for something like 5 hours to supply a total of 1 TWh. At 2 Gl of water per site, that's something like 3,300 times the volume of Lake Eucumbene (when it's full). A hugh volume of water.


If the Australian grid is to become self-sustaining and stable, we can not kid ourselves on the scale of the generation "problem". When the lights go out, it's too late to say "I should have ..."

Hi Ian,

In fact the modelling shows 450GWh (=- 30%) of reserve capacity is required for complete transition to renewable. In a 100% renewables grid, this would likely come from a mix of PHES, battery and demand management. PHES is likely to have a cost advantage over other technologies for quite a while. Reserve power needed is about 20GW

There is an interesting paper on storage options here:
https://www.climatecouncil.org.au/wp...-Australia.pdf

Ross
One day you will have to tell me who you work for, or previously worked for.

Thank you for that link.
I'm not sure it references the study I referred to above, my recollection is of a paper or report dated prior to 2016.

I take two things away from what little I read in your link.

1. If Australia is to embrace a 100% renewable electricity grid we will need to radically rethink how we fund reserve capacity. At some point we as a nation will need to accept that keeping the lights on (or the air con running) will require that we as a nation accept higher energy prices. The SA battery is proving vital to smoothing transients in the SA electricity supply, but at less than 200 MWh (after expansion) it is still too small to power the state through a night, let alone two consecutive cloudy days and three nights. The SA battery would need to be at least three orders of magnitude bigger for this task. And please don't mention the capacity "reserve" inherent in electric cars. Don't know about you, but I want my car ready to go in the morning, not sitting in the garage because its battery is flat because it's been powering the grid all night.

2. The Climate Council is not a disinterested player in this discussion. Like all lobby groups it has an agenda to push.

Can I thank all the participants in this discussion, both for the wide range of knowledge you bring and for the civil manner in which it is being carried out. May it continue.