Snowy 2 or not?

Tumut 3 power and pumped hydro station, Snowy Mountains, New South Wales, Australia Home Top Index The power station generates electricity when water flows from the upper storage, Talbingo Dam, into the lower storage, Jounama Pondage. When power is plentiful and cheap water is pumped from Jounama up to Talbingo. More information on this installation is on another page on this site; I've listed other pumped hydro sites in Australia on a page about the forms of electricity generation that are right for Australia.   Talbingo dam on the left, Talbingo Reservoir in the Tumut River valley, and the head-race for the power station in the foreground Quoting Michael Bloch writing for Solar Quotes (link below): "The Snowy 2.0 project will increase generation capacity by up to 2,000 megawatts and provide approximately 350,000 megawatt hours of energy storage when at full capacity. To be situated around halfway between Melbourne and Sydney, Snowy 2.0 would link Tantangara and Talbingo Reservoirs via approximately 27 kilometres of tunnels. A hydro power station is to be constructed at the middle point between the reservoirs, built almost 1 kilometre underground." The big question: is it the best option, or would a number of smaller schemes, perhaps some of them in the Snowy Mountains, be better? Why Snowy 2? Where did the idea come from? The concept of connecting two of the major Snowy Mountain reservoirs with a pumped hydro scheme has been discussed for a decade or more. For example, a piece written by retired engineer Peter Lang about the economics of a 9 GW scheme (much bigger than the proposed Snowy 2's 2 GW) connecting Tantangara Reservoir with Blowering Reservoir was written in 2010. This would have the advantage over Snowy 2 of about 200 m more altitude difference than the Tantangara/Talbingo connection of Snowy 2, but the huge disadvantage of needing a 53 km tunnel, twice that of Snowy 2. Why did the Turnbull government adopt the Snowy 2 idea? Was it mainly because of the huge size, the attraction for PM Turnbull to have his name associated with such a magnificent scheme and written into Australian history? Are there alternatives? There are many alternatives, for example at least four pumped hydro schemes are under investigation in northern South Australia, also see Energy Source and Distribution News (2018/02/09). And then there's the Kidston mine project – discussed below. 2017/08/03: A group under Professor Andrew Blakers of the Australian National University did a study that identified 5000 sites in Queensland, Tasmania, the Canberra district and around Alice springs with energy storage potential of from 0.9 GWh (900 MWh) to more than 100 GWh (100,000 MWh). 2017/09/21: Blakers' group releases the results of an extended study that identified 22,000 pumped hydro sites around Australia. Professor Blakers said: "We found so many good potential sites that only the best 0.1 per cent will be needed. We can afford to be choosy." Were the sites identified by Blakers' group considered, or are they being considered, as alternatives to Snowy 2? I contacted Professor Blakers by email on 2018/06/07 asking if he had shortlisted the most promising of his many potential pumped hydro sites. He replied that he had not because "Our priority at the moment is to find some carry-on funding from July". On my further inquiry about the amount of money he was seeking he replied that it was "several hundred thousand dollars". I note that $400,000 would be one ten-thousandth the estimated cost of Snowy 2; money well spent surely, if it would identify the best sites for pumped hydro storage in Australia and perhaps avoid a bad decision costing billions of dollars. Home Top Index Response time One of the great advantages of pumped hydro can be the speed at which it can respond to a need for more power in the grid. The fact that Snowy 2 involves 27 km of tunnels means that its response time will be much greater than the response time of a smaller project having only a kilometre or two of tunnels; it takes quite a bit of time to get water moving, at up to the expected 6 metres per second, in 26 kms of tunnels. Longer tunnels also result in greater friction losses (unless tunnel diameter is increased which increases costs). Centralised or distributed? An old and wise piece of advise is not to place all one's eggs in the same basket. Surely this is what Snowy 2 is doing. One of the big cost-components of an electricity supply system is in the building and maintaining of the long-distance transmission lines. A number of smaller pumped hydro storage units scattered around the nation would reduce the need to transmit the power over long distances. If a single huge development has to shut down for some reason the impacts can be enormous. If there are ten smaller developments one or another of them going off-line is not a major problem; they would also give flexibility to the National Electricity Market. In what follows I have considered the Kidston project, which is under development in Queensland at the time of writing, and the proposed Tasmanian 'Battery of the Nation' proposal, as comparisons to Snowy 2. External links David Leitch, First Thoughts, 2017/12/21, writing for RenewEconomy. Michael Bloch writing for Solar Quotes; Snowy 2.0 : Technically Feasible, Financially Viable, Very Expensive, 2017/12/21. Snowy Hydro's feasibility study (undated?) Snowy Hydro's summary of the feasibility study. Snowy 2 compared to Kidston Kidston is a combined solar and pumped storage hydro project proposed and, as of the time of writing, June 2018, partly built by Genex Power in northern Queensland, Australia. By far the strongest point in favour of Snowy 2 is its huge energy storage capacity which is far greater than any other single energy storage proposal (it remains to be seen what the total capacity of the Tasmanian "Battery of the Nation" will be). The first 50 MW of solar PV had been operating for several months at the time of writing. Another 270 MW of solar PV is planned as well as the pumped hydro installation. ARENA (Australian Renewable ENergy Agency) has committed to supplying $4 million toward the development cost of the Kidston project. Kidston pumped storage hydro project The aim is to use two existing mine pits as water storages with a possible additional turkey-nest dam added to the upper storage. Water will be pumped from the lower to upper storage using solar power during the hours of strong light. Water will flow from the upper storage though turbines to the lower storage generating power during the evening peak demand period. Water will again be pumped into the upper storage during the low-demand overnight period. And again, water will flow through the turbines generating power for the morning high demand period.

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A naïve comparison between Snowy 2 and Kidston

Notes on the table In practice only a fraction of the given figure of 350GWh maximum energy for Snowy 2 will be available at most times, a practical maximum could be much closer to 40GWh, see Snowy Hydro 2.0: More Expensive Than Battery Storage by Ronald Brakels, 2021/03/22.   Request for further information This comparison is naïve partly because I am anything but an expert on pumped hydro power, but also because I do not have all the information needed for a good comparison. I requested further information from both Snowy Hydro and Genex Power on 2018/06/05. Improving this comparison depends on the information available to me. Genex replied promptly twice. On receiving no reply from Snowy Hydro in six days I emailed again on 2018/06/11. I have received no reply by November 2020. Estimated costs The figure for Snowy 2 was the latest estimate that I had found as of October 2023 (Snowy Hydro expansion hits reset button as costs blow out to $12 billion, ABC, written by Tom Lowrey, 2023/08/31. That for the Kidston project was provided by Genex Power and is for the pumped hydro component alone; does not include the solar farm. Maximum stored energy and maximum operating time at full power Taken from the respective web sites Round trip efficiency The figure for Snowy 2 was taken from Snowy Hydro's summary of their feasibility study. The figure for Kidston was provided by Genex Power. Length of tunnels Snowy 2: from their feasibility study. Kidston: from Genex Power. Start-up time A short start-up time is very important to the value of any energy storage scheme; the length of the Snowy 2 tunnel means a long start-up time. The start-up time for Kidston was from their web site. That for Snowy 2 was an estimate based on the time for Kidston and the difference in the length of tunnels; Snowy 2's tunnel length was 68 times that of Kidston. Hours of operation per year The figure for Snowy 2 is the estimated hours at full power taken from Snowy Hydro's summary of their feasibility study (Snowy 2.0 Short Feasibility Study Report, Internet reference above; about half way down page 16). Nothing was said in the summary about the expected time of operation at less than full power; I have asked for more information but have not received any reply at all. The figure for Kidston is based on information from Genex who said that while the actual hours will depend on the final contractual arrangement, a likely figure would be eight hours generation at full power each day, 8.2 hours of pumping each day. Annual generation Calculated from the hours of operation each year and maximum power Cost per MWh Based only on my annual generation figures of the previous line, an assumed 50 year life, and not considering running costs or interest on capital. In the case of Snowy 2, if one assumes five hours per day operating at half power in addition to the 87 hours per year at full power the cost per MWh comes down to $120; ten times that for Kidston. Home Top Index Economic viability of a pumped hydro development The economic viability of any development at all depends on its income in relation to its operating costs and capital cost. The annual gross income from a pumped hydro development is the income for each pumping-generation cycle multiplied by the number of pumping-generation cycles in a year. The income from a pumping-generation cycle depends on: the buying price for the power used to pump; the efficiency of the pumping; the amount of water pumped; the selling price of the power generated; the efficiency of the hydro power generation; the amount of water that passes through the turbine. So the annual gross income of any pumped hydro development equals the pumping-generation cycle profitability multiplied by the number of pumping-generation cycles it does in a year. Like so many operations, profitability depends of utilisation. Summary, Snowy 2 versus Kidston The key factor in this analysis is the stated 87 hours of operation at full power annually of Snowy 2, stated in Snowy Hydro's summary of the feasibility study; there seems to be no information in that study about expected operation at less than full power. At 87 hours per year, 1% of the time, this seems amazingly low; by comparison, Genex Power the operators of Kidson propose doing two pumping-generation cycles each day, perhaps generating 33% of the time. From the above admittedly naïve comparison Snowy 2 has a cost ten times that of Kidston, but may generate less power! If this is credible how could Snowy 2 possibly be justified, especially when Kidston is only one of very many probably comparable pumped hydro developments around Australia? Of course the scale of Snowy 2 means that the time required for construction, and the potential for cost blowouts, will be much greater than for smaller projects such as Kidston. What about Tasmania? In June 2018 initial information had just become available from Tasmania and had been reported on the ABC. 14 possible sites had been identified with a total potential power of 4,800 MW; the more important figure, the amount of energy that could be stored (MWh) was not stated. In November 2020 I looked up Hydro Tasmania's page on "Investigating Tasmania’s pumped hydro potential". Three of the most promising sites were discussed: Site name Power MW Maximum duration of generation Energy storage GWh Tunnel length km Total cost Cost per MW Lake Cethana 600 11 hours 6.6 3.5 $900M $1.5M Lake Rowallan 600 24 hours 14.4 2.8 $990M $1.65 Tribute 500 31 hours 15.5 7.1 $915M $1.83 For comparison Snowy 2 2,000 175 hours 350 27 $5,100M $2.55 The main advantages of the Tasmanian schemes seems to be the much shorter tunnel lengths (resulting in much shorter times for starting and stopping and lower friction losses) and the lower costs per megawatt. The main advantage of Snowy 2 is the much greater energy storage.

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