Again WHOLE of FUEL CYCLE. Some small operational matter does not represent the whole fuel cycle - the cost of all that concrete and construction, etc. etc. etc. Besides operationally the snowy system only needs to pump water back when there is a lack of rainfall. They cannot possibly do that all the time.
A true Spock-like statement - CORRECT - they do not do it 24 hours a day 7 days a week.
Actually they do it nearly every day of the week and 52 weeks of the year for a number of hours a day generally between 1am and 4.30am (from memory - I knew I shouldn't have tossed out that presentation).
With all the rain (and snow) recently this is their current generation (out of total generation capacity of 3,950MW):
21 July
18:15 315 MW
18:30 320 MW
18:50
67 MW - wholesale price must be dropping off rapidly. Coal and gas are virtually unchanged and wind has only gone up by 20.
19:05 66 MW
However they pump it back up once the off-peak wholesale price hits a trigger level and they start to ease in the pumping station as the price falls further until it is pumping at 80-85% (from memory) capacity. I asked about why not higher - "Off-peak low-price goes from many hours over night and running at too high a capacity risks higher break-down/maintenance costs. If off-peak price really plummets then we temporarily raise capacity higher to maximise our earnings. Another constraint is the capacity of the reservoir and how low we can run it without causing operational issues to arise."
One of the not-so-public details in a presentation I was given as a fund manager by them back in the 2000s.
If they waited solely for rain then their output would be a fraction. Then while it is cold enough (aka snow/ice) there is minimal flow.
They are limited to where they can store the water down-mountain - so only one of the 9 hydro power stations can do this. It can account for over 95% of all power generated in a typical year with average rainfall (what NSW Treasury's co-presentation said).
The clue is given by the pumping stations:
Pumping Stations • Snowy Hydro
The one used for Tumut 3 pumps nearly 300 cubic metres (or tonnes) PER SECOND - back up the mountain. That is what chews through the La Trobe Valley brown coal-fired electricity.
The other one I don't believe is used for pumping back up for peak generation.
Try to find any mention of the use of brown coal-fired electricity used to pump the water back up-mountain daily to generate the Snowy's power - harder to find than hen's teeth!
Best I could come across is in wikipedia...
Tumut 3 Power Station
Tumut 3 Power Station is the first
pumped storage hydroelectric power station in Australia.[SUP]
[7][/SUP] Pump-storage schemes
use off-peak energy to pump water to a reservoir on a higher level. This water then passes through turbines to generate electricity when prices are higher.[SUP]
[8][/SUP] The sole powerhouse is located above ground, approximately 1,800 metres (5,900 ft) below
Talbingo Dam.[SUP]
[7]
[/SUP]
