Snowy 2.1 – pumping up from Blowering Reservoir

“Snowy 2.1” is my proposal to enhance the Snowy 2.0 pumped-hydro project design with 2 significant upgrades.

FIRST UPGRADE
– double Tumut 3’s pumping power

Tumut 3.1 – 1.8GW/1.2GW

Doubling the pumping power at Tumut 3 – from a nominal “600MW” to “1,200MW” by upgrading the generation-only units 1, 2 & 3 to pumping-also operation just like units 4, 5 & 6 which can already pump as well as generate.

This increases the water pumping rate by about another 300 cubic metres per second to a total of 600 cubic metres per second.

Currently, Tumut 3 has only 600MW of pumping power and can recharge just 9GWh of energy because of Jounama Pondage’s limited water storage capacity.

SECOND UPGRADE
– Jounama pumped-hydro 100MW

Jounama 2 – 0.1144GW/0.1GW

Building a 100MW pumped-hydro power station alongside the 14.4MW Jounama Small Hydro Power station, for 100MW of additional power generation or energy storage when the water level in Blowering Reservoir allows.

100MW should allow for a water pumping rate from Blowering to Jounama of about 275 cubic metres per second, about the same rate as Snowy 2.0 pumps up at full power.

Alternatively and synergistically with the Tumut 3.1 upgrade, if the designed power rating of Jounama 2 was ambitiously 220MW rather than moderately 100MW, the water pumping rate could match the total pumping rate of Tumut 3.1 of 600 cubic metres per second to refill Talbingo, though Snowy 2.0 could not match this pumping rate to refill Tantangara.

Jounama 2 of whatever wattage also removes the limitations on the volume of water that Tumut 3 can pump up from the limited 28GL capacity of Jounama Poundage to as much as the 399GL of Talbingo’s and Tantangara’s capacity combined – an increase by a factor of 14.

In a wet year, Jounama 2 would effectively double the rechargeable energy storage capacity of the Snowy Hydro scheme – and that’s a lot of storage bang for the buck!

Jounama Small Hydro Power Station

Jounama Small Hydro 14.4MW. 13m diameter turbine silo. A 4m diameter steel pipeline under the dam.

A Jounama 100MW pumped-hydro power station would generate about 7 times more power than the 14.4MW Jounama Small Hydro Power Station so many critical dimensions of the design will be about √7 times wider.

• 35m diameter silo
• 11m diameter steel pipeline under the dam

BENEFITS
Snowy 2.1  (4.1GW/3.5GW 500GWh)

  Snowy 2.0 ( 2.2GW/2.2GW)
+     Tumut 3.1  ( 1.8GW/ 1.2GW)
+ Jounama 2    ( 0.1GW/ 0.1GW)
___________________
=     Snowy 2.1  ( 4.1GW/3.5GW)

Snowy Hydro’s plan is that Snowy 2.0 (2.2GW/2.2GW) & Tumut 3 (1.8GW/0.6GW) deliver between them 4.0GW/2.8GW generating / pumping though Tumut 3’s pumping would still be limited to 28GL & 9GWh.

This enhanced plan for Snowy 2.1 adds +0.1GW/+0.7GW generating / pumping & +259GWh energy storage whenever the water level in Blowering Reservoir is sufficient to allow pumping up to Jounama Pondage.

The benefit of Snowy 2.1’s two upgrades combined (Snowy 2.0, Tumut 3.1 & Jounama 2) is to allow for the fast recharging of all and more (up to 440GWh when Tantangara is refilled from Blowering and then a further 61GWh when Talbingo is refilled from Blowering to a grand total of ~500GWh) of Snowy Hydro’s claimed “350,000 megawatt hours” of energy storage.

The Snowy 2.0 over-hyped claim of “350GWh” will in practice be limited without these upgrades to more like just 2/3rds of that claim (233GWh) because 1/3rd (79GL) of Tantangara Reservoir’s active storage volume of water (239GL) may be “lost to Blowering” (and be unable to be pumped up again) following a period in which the upper reservoir has been fully discharged.

Schematic of Tumut and Snowy 2.0 Reservoirs, using Snowy Hydro’s stated (active storage) volumes, with approximate surface elevations too.

LIMITATIONS AND SAFEGUARDS

With Snowy 2.1, there can be no pumping water up from Blowering from a Jounama pumped-hydro power station when the active storage percentage or dam level is significantly below 60%, which is an intrinsic technical limitation but which is fortunately also a safeguard against Snowy Hydro extracting water from Blowering Reservoir at times when WaterNSW believe that Blowering’s water may be in short supply.

When the water level at Blowering Reservoir exceeds 357.5 metres above sea level, the turbine access hatch to the Jounama silo becomes submerged by water.

When Blowering Reservoir is significantly less than 60% full (362 metres elevation), a Jounama pump couldn’t operate, which would suit WaterNSW just fine.

There can be no generation down into Blowering when the storage is 100% full or when WaterNSW has issued a flood warning for Blowering Reservoir, which is a good-management limitation which should be enforced by technical automated control means in order to safeguard against flooding.

See also –
Snowy 2.0 Headrace Tunnel Rescue Plan
Snowy 2.0 design botch – water hammer
Snowy 2.0 Headrace Surge Shaft & Tank Design
Active feral horse shooters blackmail Snowy 2.0