Energy Storage: An Estimate Using Actual Data

By Mike O’Ceirin

Energy Storage:  An Estimate Using Actual Data


Much has been written about using energy storage to stabilise renewable energy. This article uses actual data to present a theoretical answer to what may be achieved. The pattern of demand comes from actual Australian data as does the wind output. This has been put onto a website for public access and to be referenced by this article. The conclusion is that in the Australian environment on our eastern grid using wind and Pumped Hydro Energy Storage (PHES), for every TW hour 500 MW of wind and storage of 22 GW hours is needed for stability to match the existing demand pattern.

Requirements to maintain Status Quo

Australia faces five closures due to age of coal stations by 2034.

Asset nameYearCapacity MWDispatch 2020State
Vales point B202813203.6%NSW
Yallourn W202814804.5%Vic

Since the Australian demand for electricity on the eastern grid in 2020 was 203 TW hours, renewables need to dispatch an extra 55 TW hours per annum to replace them. This cannot be done just on average. The same pattern of electricity demand must be satisfied. To do this theoretically wind and PHES has been chosen.

This estimate shows that to supply that amount of electricity under Australian conditions on the east coast 27 GW of wind generation and 1182 GW hours of energy storage will be needed.

Capital costs for the wind according to Gencost 20 – 21 (page 17), at $2000 per kW hour would be $54.3 billion plus a large cost in transmission lines. For the cost of PHES see appendix storage costs.

Energy storage is nowhere near as determinate as the renewable energy sources. PHES is a bespoke item which has extreme variation in price. Certainly, there will be a long-time frame for the building of PHES and producing sufficient to meet the requirement. According to this estimate the task of producing such a large amount of electricity storage may well be prohibitive. For the Gencost estimate the PHES would cost $62 billion and a Kidston (see appendices) equivalent $456 billion. Note that this cost has been minimised by assuming willingness to run at critical levels. In a practical world this would be unacceptable.

PHES Estimate

This is only needed for variable renewable energy since energy storage is not needed otherwise. Specifically, it applies to wind and solar production of electricity. This article concentrates on electricity produced from wind. The technology for the storage is confined to PHES. The reason for choosing that for electricity storage is its capacity and cost.

The estimate relies on data (see appendix Data Source) held on the author’s website Spasmodic Energy. This estimate uses the patterns of electricity production and consumption derived from that data.

First the demand must be known. The demand for electricity on the eastern grid in 2020 was 203 TW hours, on average 23 GW. For calculations of the energy demand this is not sufficient.

The electricity demand chart (figure 1) shows the pattern. On any day, demand is greatest in the early afternoon and the lowest in the early hours of the morning. This is expected and must be taken into consideration when calculating the energy storage requirement. It is suggested that estimates such as this should be done against a full year since there is a definite yearly pattern. By that means the low and high points of the year for wind will be included.

Using actual data an estimate has been made by stepping through each actual hour.

This is shown graphically on the energy storage page (figure 2). The pattern of the dispatched electricity is shown in the lower chart superimposed over the actual output of wind for the chosen time period. For each step, the assumption is made that the initial percent can be achieved. The steps to solving this are as follows.

  1. Is there enough electricity from wind to supply the demand for that hour?
  2. If so, add any excess to storage less 15% (to account for storage losses).
  3. If not, then draw enough from storage (there is a 15% loss here as well) to satisfy the demand.
  4. If storage has gone to zero or below then the run has failed. Reduce the demand percent by one and start again at the beginning.

The output is shown in figure 2. This is a run for the whole of 2020 starting with an initial charge of 350 GW hours and an expected demand of 10%. The demand is an expected percentage of the total demand for that year. As above it can be seen (on the right) that 10% failed as did 9% finally settling on 8%. The result is then displayed in the two charts. The top one shows the charge of the storage throughout the year. In the example it is stable until the end of January and then it falls and keeps on falling until early March where it sits at practically at zero for many days. The storage gradually builds up to become fully charged at the beginning of May.

Please note that the displayed example is static while the actual website is not. There the whole picture can be seen throughout the entire year by scrolling the display. This was found to be quite important since trying to display that amount of information in a static chart does not show what happens. The charge drops again to under 50 megawatt hours in August to again rise to a full charge at the end of August which remains until the end of the year.

The second chart shows what the result is. It is clear that energy storage reduces the amount of usable electricity. In 2020 wind dispatched 19.68 TW hours but it was not stable. If it is stabilised using energy storage the usable wind energy drops to 16.22 TW hours. The cost in this case for stability is a loss of 18%. There is the overhead of the energy storage of 30% and when it is fully charged potential electrical generation is lost. In the energy storage chart figure 2 this can be seen in September (if scrolled).

Why is this so? It seems very extreme. The point is wind droughts are frequent and can be long. These can be found on the website under “wind droughts”. In 2020 many instances can easily be found where the capacity factor drops to under 5%. There is one extreme case where the average was 5.5% for 33 hours. There are others where the drop is to 2%. Despite the fact that the Australian eastern grid is very large, covering many thousands of square kilometres, the wind patterns are larger. The whole of Australia can easily have little wind also too much wind.


To stabilise wind energy generated during 2020 so that it is congruent with the demand 350 GWh of energy storage was needed. That will meet 8% of the demand using the existing wind infrastructure of 2020. The capacity of wind was 8 GW and 8% output is 16.22 TWh. So, for 1 TWh 0.5 GW of generation is needed. As a rule, 22 GW hours of storage are needed to stabilise 500 MW of wind.

As previously stated, five major coal stations will close before 2034 on the Australian eastern grid. Together they currently generate 27% of the electricity on the eastern grid. That is 55 TW hours so applying the rule 1181 GW hours of electricity storage will be needed. At a minimum cost of $52 million per GW hour the total would be $61.5 billion.


Source Data

Australia has a grid along the whole of the eastern coast which connects generators. That grid is monitored by the Australian Energy Marketing Operator AEMO who records and publishes pricing and performance data at five-minute intervals. That data is used in this estimate. To enable the use of this data on a website it has been transformed to hourly data. Currently there are 150 million data points. Wind is used as the source of the renewable energy which in Australia is spread over a large area.

Pumped Hydro Energy Storage (PHES)

This estimate assumes that this can be provided with sufficient capacity. To estimate the cost the Gencost 20-21 study (page 19) can be used. In Australia there is a proposed large PHES to be built known as Snowy Mountains 2.0 (SM 2). It is projected to be able to deliver 2000 MW for 175 hours. This results in a capacity of 350 GW hours. The default trial figure is the same, but other figures can be applied of course to the storage page of the website.

Gencost gives a cost per kW and that cost is for 48 hours. The cost for 2000 MW on that basis is $5 billion. Matching it to 350 GW hours means it must be multiplied up and the result is $18 million of $2 million per GW hour. The Snowy Mountains 2.0 as previously stated is the same as this in capacity. The cost that has been often stated is $10.4 billion. That makes it far cheaper than the Gencost study would allow, even though the cheapest has been chosen out of that study, since much of the work has already been done. Possibly it is an exception.

Kidston is being built in Queensland in an old gold mine. Compared to SM 2 there are significant differences. It is much smaller and much more costly. The capacity is 2000 MW hours. The cost is $386 million per GWh.

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Rud Istvan
August 12, 2021 2:39 pm

Showing yet again that any significant penetration of intermittent renewables into a reliable grid is financially ruinous because of the need for backup (here, PHES in the specific form of SM2).

John Bell
Reply to  Rud Istvan
August 12, 2021 2:46 pm

And also showing that ALL renewables are totally dependent on fossil fuels to build them, maintain them, and remove them at end of life. The very fact that we can build wind turbines is alone proof that they are not needed.

Bryan A
Reply to  John Bell
August 12, 2021 6:54 pm

The POX will flatten the Byzantium plumage …
More word salad from M Ingraham

john rattray
Reply to  Rud Istvan
August 12, 2021 9:43 pm

Actually it is nowhere as bad as the author makes out as his analysis assumes a wind only R.E. generation. Solar and wind are not closely correlated and in many parts of S.E. Australia the correlation is actually slightly negative. This will substantially reduce the need for everyday storage. It is also a mistake to assume that all storage is alike and needs to have the same operating profile. For instance, most new utility sized solar farms are now including in their design 2 to 4 hours of storage due to both the very low (often negative) prices around solar noon and the very high prices (often > $100 MWh) during the evening peak. For the operators, the additional cost (about 30% of capital spend) is more than made up by the ability to sell into high priced intervals.

In my opinion the actual economic problems come from:

  • The continued reduction in day time prices caused by small scale roof top installations, which is having significant impacts on base load generators who must generate during these periods due to physical constraints;
  • A requirement for long term seasonal storage and the consequences of being able to turn over the storage only a few times a year rather than once or twice a day. I have yet to see any economically priced answer to this.
  • Substantial curtailment due to seasonal lows in average daily energy demand being much lower than the seasonal highs.

Having said that, the Tomago Aluminium Smelter has just announced that it wants to go 100% R.E. when its current contract runs out in 2029. The smelter has a base load of 850 MW, implying on a 30% capacity factor, that it will need additional R.E. builds of about 2.5 GW to support it at a cost of somewhere in excess of $5 Billion. This in turn implies that the market demand will swing an additional + $850 MW to -1.65 GW depending on the generation output of the new R.E. builds. That’s going to have a significant impact on other generators who share the same production profile and also on prices during periods of low production.

Interesting times.

Reply to  john rattray
August 12, 2021 10:36 pm

Wind RE was chosen since the data shows that it is much more favourable to electricity storage. Yes it does have wind droughts but solar effectively has a wind drought for most of every day. The capacity factor of wind here is 28% but solar is 18%. In Australia it is far less than wind for grid solar and rooftop solar which is much larger is an estimate. I have not gone through the same steps for solar but my expectation it is a much worse option.

john rattray
Reply to  Mike O'Ceirin
August 13, 2021 2:45 pm

It is not a case of one or the other. It is the combination of the two that provides a benefit. This is an example of portfolio theory in which you are trying to minimise variability by including diversified assets, including some with a lower return.

Don’t get me wrong, I think that the work you have done is both valuable and difficult. It’s something that AEMO refuses to do or at least to publish the results. Though whether that’s because of incompetence or political conspiracy I will leave up to others to decide.

As an aside wind in the southern states has a large frontal component which typically brings clouds and therefore reduces the day time solar. component. This component during the winter is effectively random as to time of day. However in the summer months wind has a much stronger time of day component peaking in the late afternoon early evening, (due to thermal flows?) This is the reason for the slightly negative correlation.

Speaking of diversification a mixture of R.E., storage and fossil fuelled generation is likely to provide both adequate diversification of supply and lowest cost generation. (Roof top solar matched to local demand for instance is very effective as it misses the approximately 10-15% system losses that large centralised generation incurs) Unfortunately this is not what Australia is going to get.

Reply to  john rattray
August 13, 2021 5:04 pm

I started the work on wind and PHES thinking it would be much more effective than it turned out to be. Since there is an interest I think I will work on being able to do the same thing for a wind solar combination or solar in isolation. I don’t think you will like it since my expectation is the situation will be worse.

Reply to  Mike O'Ceirin
August 14, 2021 3:45 pm

Keep in mind that both EIA and IEA treat homeowner/private installations of solar as gifts that give forever.

There is no process that provides a mechanism for homeowner/private installations of solar to remove their solar arrays and thermal solar from national lists.

Instead, the agencies happily apply new efficiency ratings retroactively.

Replacing homeowner/private solar installations only results in the agencies incrementing homeowner/private installations.

Reply to  john rattray
August 12, 2021 10:39 pm

Wind and solar have a high correlation

NO Solar at night
Wind is highly unreliable

Reply to  John
August 14, 2021 3:46 pm

And no solar during substantial portions of winter and rainy seasons.

Peter K
Reply to  john rattray
August 13, 2021 12:03 am

Newer Coal Fired generators are rated at 1GW and will run 24/7. There is a lot of real estate required to build 2.5 GW of R.E. The main problem is getting that 30% capacity to be available 24/7. The cost of installing a back up battery, with the capacity to fill in the gaps, would be mind boggling.

Reply to  Peter K
August 13, 2021 5:31 am

quotes on a smalllocal battery for a Vic town was 250K + and town was expected to find half that

Reply to  ozspeaksup
August 14, 2021 3:50 pm

$250K Australian?

For what, a warehouse full of lead-acid batteries?

That cash wouldn’t buy many minutes of backup lithium battery power.

It doesn't add up...
Reply to  john rattray
August 15, 2021 10:24 am

Done the studies myself. It turns out that the degree of complementarity is rather less than you infer. Also, the idea of negative correlation is wishful thinking, and Dunkelflaute is real.

It doesn't add up...
Reply to  john rattray
August 15, 2021 2:43 pm

The real problem is not really intra day, for which relatively modest amounts of storage are required. Rather, it is the longer periods of low renewables output that give rise to difficulties and the need for lots of storage.

Here’s a chart showing wind output in South Australia and New South Wales at 5 minute resolution over a year. Anti-correlation would see the points sloping nicely downhill, so when it’s windy in one state, it compensates for lack of wind in the other. The unfortunate feature of the chart is the dense cluster of points close to the origin, which means that there are long periods of time when there is little wind in either. The general tendency is for positive correlation. Some banding in the chart is due to wind reaching maximum levels, and due to expansion of capacity during the year. The mutual high winds imply that there would be substnatial surpluses in an all renewables grid. These must either be stored or spilled.

SAvNSW wind.png
Reply to  It doesn't add up...
August 26, 2021 5:33 am

I thought when I started this that it actually would show a considerable stability because of the large area. Our eastern Grid starts in the top of Queensland and finishes in Tasmania. this is an area 1500 km by 2500 km. Currently we have about 8 GW spread across that you can see that it is more stable than it was say five years ago when the amount of wind stations was much smaller. I have not quantified it but it is not much. Here,-32.12,1153 you can see the wind patterns and it is obvious they are very large. At the moment there is practically none over three quarters of Australia.

It doesn't add up...
Reply to  Rud Istvan
August 15, 2021 10:21 am

I will have to see if I can still find the work I did on a 100% renewables study produced for AEMO by Prof Andrew Blakers in about 2012. I recall that to provide adequate storage for a renewables grid required on the order of 10TWh for the Eastern grid. Blakers came out with only 350GWh being needed, but it transpired that his model of wind and solar generation was created by only looking at replicating short term average correlations in weather across the geography. This matters, because it does not create the real world longer and wider geographical scope periods of Dunkelflaute, nor features such as a bad weather year for renewables.

I do remember he assumed that far North Queensland offered a less correlated supply. I looked at the implications for Thursday Island in the Torres Strait, which despite being so close to the equator was going to need large amounts of storage. In fact, to minimise storage required, massive over-investment in renewables with associated curtailment and spillage was the cheapest option if you denied dispatchable generation.

Reply to  It doesn't add up...
August 26, 2021 5:39 am

I know Blakers report one thing I noted was a study that claimed wind was stable because he had tracked it for a few days. I have found there is a yearly pattern it decreases in winter for instance. The other thing I noted was he expected to build many PHES. The environmentalists drive this and they are against hydro the very basis of their Greens party was the stopping of the dam in Tasmania. Also if you look at California they do not want to build anything which is hydro. I expect we will get large opposition if you try to build much beyond what is being built in our snowy Mountains.

August 12, 2021 2:54 pm

Disruptive iron-air grid storage battery is 10% the cost of lithium. There is always a “new and/or improved” battery. Just build an MSR powered by thorium and forget this battery-wind-solar -green stuff. It will have to be done one day anyways – why not start now. Good, it’s settled.

Russell McMahon
Reply to  Anti-griff
August 12, 2021 5:13 pm

Sadly, Thorium MSR is far harder than is generally stated in popular media. The Chinese have taken a fast track approach and suggested that they’d have the technology available in ten years. That was a few years ago and MAY still be 10 years. That approach uses Thorium extremely inefficiently with source depletion of all known reserves in tens of years aND they do not hold the majpor sources and will almost certaonly not have access to them – they are in India.
The Indian approach uses a breeder chain with U235 and Plutonium systems allong the way, producing far mote Thorium as a result. This was projected to take 40 years, with the road map up[dated and made public annually. This requied suitable funding and a stable construction program. About 2? years ago it as clear the plan was going well off track and the political statements then made made it clear that the politicians did not care and/or understand and that proper funding wasnot to be made available.
All the above is well enough documented online. Sadly.

Reply to  Russell McMahon
August 12, 2021 10:40 pm

The US had a reliable Thorium reactor
President Nixon shut down the program because he wanted Plutonium for weapons

Patrick MJD
Reply to  John
August 13, 2021 12:08 am

Well, that was the case for all leaders at the time. Electricity was just a waste byproduct and an excuse to build plants. Power too cheap to meter.

Reply to  John
August 13, 2021 6:59 am

A lab setup does not qualify as a reliable reactor.
There are still huge problems that have to be over come before a commercial grade reactor can be built.

Gordon A. Dressler
Reply to  MarkW
August 13, 2021 9:17 am

The first efforts to develop a MSR were associated with the Aircraft Nuclear Propulsion (ANP) program and the preceding Nuclear Energy for the Propulsion of Aircraft (NEPA) project. The United States Army Air Forces initiated Project NEPA in 1946. The project included experiments, including high temperature and engine tests collectively called the Heat Transfer Reactor Experiments: HTRE-1, HTRE-2 and HTRE-3 at the National Reactor Test Station (now Idaho National Laboratory) as well as an experimental high-temperature molten salt reactor at Oak Ridge National Laboratory – the ARE.

ARE used molten fluoride salt NaF-ZrF4-UF4 (53-41-6 mol%) as fuel, moderated by beryllium oxide (BeO). Liquid sodium was a secondary coolant. The experiment had a peak temperature of 860 °C. It produced 100 MWh over nine days in 1954.

An MSR was operated at the Critical Experiments Facility of the Oak Ridge National Laboratory in 1957.

So, over some 60+ years, this “promising” MSR technology has failed the catch the attention of all major commercial power plant manufacturers, including those that specialize in commercial scale nuclear power plants, with all the attendant capital costs, siting and licensing problems related to them.

Also, the US Navy, with every reason to be focused on the inherent safety and reliability for the compact nuclear reactors it uses on submarines and aircraft carriers, has obviously seen no reason to pursue MSR technology . . . ask yourself why.

These facts alone should tell you that even today, we are far removed from having a commercially viable MSR power plant.

“Fools rush in where angels fear to tread” — Alexander Pope, 1711

Reply to  Russell McMahon
August 13, 2021 1:57 am

Sadly I agree, whatever the longer term choices are, right now what the world needs is proven technology that can be deployed quickly.
That aint the EPR and it aint molten salt.

Probably a toss up between ABWR and SMR…the renewable scam is going to blow up not because it doesnt work, or because anthropogenic climate change is debunked but because of the eye watering costs.

ClimateChange™ will limp on because no one dares admit it was all a fraud, and it will gradually become ‘less serious than we thought’ and ‘cheaper to adapt to than prevent’.

To be honest, at current oil prices unless you have coal to burn locally, nuclear is a better bet anyway.

The Green Luddites will in the end lose, fossil fuel will slowly price itself out of most of the energy market and some sort of new lifestyle will emerge.

Cities used to be places people traded, then they became places people manufactured. Now they are just places people live.

The internet is where people trade, and robot farms are where stuff gets manufactured.

Devils tower
August 12, 2021 3:04 pm

I did not know until just reciently lake Oroville in calif is setup for hydro storage regeneration. To use it they need excess off peak power generation to pump the water and the water to pump. Going back thru the article agaiin. The efficency loss of storage to regeneration did not pop out on first read.

Does not seem to be working at Lake Oroville.

Back in the 70’s some dude from calif took a job with an iowa utility. He was pushing to build a dam and do regeneration pumping using water from the Mississippi river. Common sense in iowa got his ass kicked back to calif.

It was a long time ago, I know it was all over papers then.

Reply to  Devils tower
August 12, 2021 4:44 pm

PG&E operates a pumped storage facility called the Helms in the Sierra Nevada east of Fresno. It has 3 X400MW turbine plants and was built in conjunction with the Diablo Canyon nuclear plant in the 70s. It is a brilliant and elegant combination that allowed them to keeping running the nuke plant at high efficiency during off hours to bank power for peak demand.

As I understand it they need to pump in 4MW to get 3MW back out. So with 2GW of nuke they can bank about 10GWhr every day.

California is really going to start crumbling when Diablo goes away in 2025 because they cancelled plans to extend the license.

Reply to  MDN
August 12, 2021 4:45 pm
Devils tower
Reply to  MDN
August 12, 2021 5:26 pm

The really crazy thing here in Iowa, the plan was to dam the entire cedar river valley south of hyway 6 to the mississippi bluff. The amount of farm land it would have taken out was incredible.

Mike McMillan
Reply to  Devils tower
August 13, 2021 1:13 am

It would have put Wapello and Columbus Junction under water, too, for only about 60 feet of head.

Gordon A. Dressler
Reply to  MDN
August 14, 2021 8:32 am

It would be very surprising to me if they ever actually achieved the 75% round trip efficiency that you stated (3 MW returned for 4MW input). Hydraulic pumps and turbines just aren’t that mechanically efficient.

Gordon A. Dressler
Reply to  MDN
August 14, 2021 9:04 am

I would be very surprised if the Helms facility ever achieved an average 75% round trip efficiency that you stated (3 MW power out for 4MW power input).

Hydraulic pumps and turbines just aren’t that efficient when forced to run over ranges of inlet pressures and outlet back-pressures (i.e., not at a single optimized design point). And this would particular true in the case of Helms, where the designers chose to use pump-generators which serve a dual role: the pumps are “reversed” for use as the generators (the turbines).

It doesn't add up...
Reply to  Gordon A. Dressler
August 15, 2021 12:14 pm

Designs normally have a number of units in parallel which means that output or input can be varied by changing the number of operating units while keeping them close to optimal operation. 75% is certainly achievable for a pumped storage installation.

Gordon A. Dressler
Reply to  It doesn't add up...
August 16, 2021 9:47 am

75% (round trip efficiency) is certainly achievable for a pumped storage facility

Maybe, but if so, if it hasn’t been demonstrated at the Helms facility over any significant length of time.

The attached chart is from:

and it shows the best Helms ever achieved was 73% during the operating years 2000-2007 (I could not locate more recent data):
YearRT efficiency
2000 — 73%
2001 — 65%
2002 — 67%
2003 — 66%
2004 — 73%
2005 — 68%
2006 — 69%
2007 — 67%
avg = 69% RT efficiency

John Swallow
Reply to  Devils tower
August 13, 2021 4:10 am

It is a fact that Pumped storage is the only proven way to store electrical energy but as this states below, it uses more power than it generates. 
“Pumped storage hydroelectricity generation is negative because most pumped storage electricity generation facilities use more electricity than they produce on an annual basis. Most pumped storage systems use fossil fuels or nuclear energy for pumping water to the storage component of the system.” 

If wind and solar, why after the billions of tax dollars spent on them, do they only supply 6.5% of the US’s electrical energy.

Steve Z
Reply to  Devils tower
August 13, 2021 12:50 pm

Hydroelectric power needs lots of water and an elevation difference. Not much of an elevation difference in Iowa. Iowa gets plenty of snow, but there are no ski resorts there–can anyone guess why not?

It doesn't add up...
Reply to  Devils tower
August 15, 2021 10:28 am

The article refers to 15% losses on each leg for an implied round trip efficiency of 72.25%, being 0.85^2.

Gordon A. Dressler
Reply to  It doesn't add up...
August 16, 2021 8:54 am

Love the precision to four significant figures when calculating round trip efficiency using a two-significant-figure input value.

Rafe Champion
August 12, 2021 3:08 pm
Gary Pearse
August 12, 2021 3:13 pm

In an earlier age, people would think this society insane to to choose a grossly inadequate and expensive form of energy for their ‘baseload’ and shore it up with storage that’s even costlier and wastes 30% of the energy input into storage. Perhaps the Snowy Mountains storage can be rigged to recharge itself like regular hydro?

Reply to  Gary Pearse
August 12, 2021 4:04 pm

Pumped hydro storage has proven economically effective in certain locations for more than a century. link Certain locations … aye there’s the rub. As far as I can tell, the situations where it is actually viable have already been exploited.

Reply to  commieBob
August 12, 2021 4:34 pm

Historically, what’s the use case for pumped hydro? As far as I can tell, it’s something like the following:

There is an elevated basin in proximity to a market. It can’t require extensive dams.

The total hydro plus (probably) coal has to be sufficient for the peak expected load. That means your coal generation can be quite a bit smaller and you save on the capital cost of building the larger station that would be required to carry the peak load all by itself.

The smaller coal powered generator could be run near peak efficiency more of the time, so there should be some saving in fuel. Presumably, there would also be some saving in labor.

The money saved on the coal powered generation would help offset the cost of the hydro facility.

At night, water is pumped up hill and during the day, when the load is greater, the water discharges through the turbines. Because the load and supply are relatively reliable (ie. predictable), you need to store only enough water to get you through the next day.

If the necessary conditions are met, pumped hydro has proven to be viable.

As far as I can tell, using pumped hydro to back up windmills fulfills none of the conditions that would normally make pumped hydro viable.

Last edited 10 months ago by commieBob
Rud Istvan
Reply to  commieBob
August 12, 2021 5:50 pm

Pumped hydro has been traditionally used for peak load shifting only. Pump up at night letting thermal Gen plants run at max efficiency 24/7, then draw it down during afternoon/evening peak loads. Depends on terrain and peak loads. Much more is available on line.

Iain Reid
Reply to  Rud Istvan
August 13, 2021 12:12 am


the real benefit of pumped storage and one of the fundamental reasons for it (It also applies to chemical batteries) is the ability to go from zero to maximum power in seconds. (the Dinorwic pumped storgae in the U.K. can go from zero to 2 gwatts + in twelve seconds I think) It means that sudden loss of generation or sudden large loads drawn from the grid can be stabilised with storage.
Such critical events are also supported by the very large inertia of conventional power plants. Wind and solar do not have this property and this is a well known fact by engineers. Removing conventional plant and adding renewables is just asking for trouble.

Reply to  Iain Reid
August 13, 2021 5:13 pm

I chose PHES because of its capacity no battery comes near it. Batteries are toys if you expect them to produce stability. It is sobering that in 2020 the whole of our wind network which is extremely large in area averaged 5.5% for 33 hours.

Reply to  commieBob
August 13, 2021 2:08 am

Bob, I think you are spot on.

When I talked to CEGB engineers back in the day about Dinorwig and Fffestiniog pumped storage the economic rationale was that they were cheaper than a 2GW power station that would only be run once a day.

In the UK there is a huge evening peak as everyone goes home from work on electric trains, gets in, switches on the lights, bangs on the telly and pops the kettle on for a cuppa before cooking their tea and settlingg in to watch Coronatrion Street. Allegedly. Suer LED lights and LCD tellies have reduced it a bit but its still there.

That is what we designed pumped storage for. not for operating against a 20GW variable wind load and 20GW of solar power that vanishes at sunset.

Saying that storage will solve renewable enertgy problems ignotres the fact that it is already three times the pricee of fossil, and storage can only increase the holistic cost, and the fact that handwaving the problem away doesn’t take any account of the hard calculations that show that storage on a scale that is almost inconceivable and has never been attempted is being pencilled in at completely unknown cost and safety factors.
The only variable of interest is how loing befre the public at large realize it simply isn’t going to work and demand nuclear instead…

Rafe Champion
Reply to  commieBob
August 12, 2021 8:55 pm

Possibly the biggest PH plant in the world at Bath PA delivers 3GW on the back of nuclear and coal burners that can run at their optimum day and night, pumping water when demand is low.

Tim Crome
Reply to  Rafe Champion
August 13, 2021 1:25 am

This was the biggest civil engineering project in the UK when I was a student. Dinorwig pumped storage (1.8GW) to allow nuclear to run at constant load.

Zig Zag Wanderer
Reply to  Gary Pearse
August 12, 2021 5:23 pm

In an earlier age, people would think this society insane to to choose a grossly inadequate and expensive form of energy for their ‘baseload’ and shore it up with storage that’s even costlier and wastes 30% of the energy input into storage.

Just imagine what future generations will think

Reply to  Zig Zag Wanderer
August 12, 2021 7:17 pm

some significant part of today’s western society IS quite insane. It sometimes seems like the condition spreads more readily than any infectious virus.

Tim Crome
Reply to  AndyHce
August 13, 2021 1:26 am

especially amongst the political and media populations!

August 12, 2021 3:55 pm

1) At the moment a lot of eggs are in the SA basket. Wind farm output % of capacity varies per farm. Increasing the wind generator capacity in locations further away from SA helps to flatten the peaks but the periods of low wind across AEMO grid still occur.
2) Increasing solar PV can help offset the low wind periods but has it’s own variability. Rooftop solar generation & usage are not all seen by the grid. Some meters are smarter than others but I’m not sure of the exact current state. I think AEMO reports grid scale solar and a renewable energy site estimates rooftop solar PV generation & demand (the unseen) based on X times the grid scale.
3) Having a full battery at the start is not required but consider a test case of unrestrained battery capacity. Look at the max minus min used so the starting MWh charge is set for your arbitrary date based on the ideal scenario. Further safety margin & multi-year variation are then added to the size required.
4) It’s hard to grasp when & how much the losses are in an electrical grid. Sometimes the generation numbers are discounted by assuming losses, sometimes reported demand is increased to represent the demand on generators to make up the losses. The worst case is when the storage is distant from the generator & distant from the users. If storage is close to generation then charging has lower losses and similar transmission losses compared to it’s source. If storage is closer to the load, the losses while charging increase but transmission losses to the load is less. Losses could also be 8% while charging from local source & 7% while discharging and 1% of MWh capacity per month for natural losses & control overhead.
5) Simulating use of pumped hydro & various X% of yearly demand using fossil fuel adds complexity to the scenarios.
6) Multiple sim runs could be done to try to optimise the perfect mix of generation & storage.
7) Cost of having users be more tolerant of load control & load shifting. We can’t assume we can turn off people’s aircon during heat wave or a smelter for too many hours per day all through summer. Winter peak demand also has problems. Autumn & spring see less demand for heat/cool but excess generation can be too much.
8) So you then need excess generation capacity which you often not use (waste) to hope you have enough for future years because generation & demand varies an every time scale. Some predictable, some very unpredictable.
The cost of using renewables rises exponentially as you approach 100% renewables.
I’ve been wanting to do a similar analysis but didn’t have enough hourly data (or better) to cover a whole year.

Reply to  tygrus
August 12, 2021 5:54 pm

The optimum mix for Random Energy (RE) in a fossil fuel dominated grid is zero RE. The first serious penetration hurdle is reached around 20% for solar and 30% for wind or a value that is a combination of these. Essentially, once the penetration approaches the natural capacity factor of either technology, the only way to go beyond the natural capacity factor is storage and/or poorly utilised excess generation that gets curtailed.

The NEM in Australia is already observing daily negative pricing and voluntary curtailing of RE output.

Although solar is lower capacity factor than most wind generators in Australia, solar is more regular. Mainland Australia has around 99.9% certainty of 2 hours of full sunshine in 48 hours around the coast and better inland. Wind can go missing for almost 2 weeks at a time. But a combination is likely best.

All that said, there are very few countries that can produce reliable supply from RE at a cost competitive with Australia; Norway and New Zealand with hydro dominated grids are better placed.

Battery storage under AUD100/kWh would make many detached suburban properties in Australia candidates for off-grid power.

Reply to  tygrus
August 12, 2021 8:05 pm

Even small Australian towns with lots of sun and wind, still need to run hospitals and other critical infrastructure 24/7. Off the Grid is not possible.

August 12, 2021 3:59 pm

I don’t know how anyone can sensibly respond to their idiocy of so called renewables.
S&W backed up by Hydro are a TOXIC, super expensive disaster and the entire toxic mess will be buried in landfill every 20 years.
But we also know that the entire SH is already NET ZERO and the NH is the NET SOURCE of co2. SH population 0.8 billion and NH 7 billion.
See CSIRO Cape Grim Tas site below and their Seasonal Variation.

“Seasonal variation””Carbon dioxide concentrations show seasonal variations (annual cycles) that vary according to global location and altitude. Several processes contribute to carbon dioxide annual cycles: for example, uptake and release of carbon dioxide by terrestrial plants and the oceans, and the transport of carbon dioxide around the globe from source regions (the Northern Hemisphere is a net source of carbon dioxide, the Southern Hemisphere a net sink).
The Cape Grim baseline carbon dioxide data displayed show both the annual cycle and the long-term trend.”

Bill Burrows
Reply to  Neville
August 12, 2021 5:56 pm

Australia has already achieved net zero CO2 emissions (in terms of the Paris Agreement). The government’s Department of Industry, Science, Energy and Resources has advised “that for the Paris Agreement all lands will be accounted for – without restriction” (compared with only about 1% of the land mass included in Australia’s Kyoto Protocol accounts.  See Submission #588, pp. 12-13 in: . This is an extremely important position to have been adopted in terms of accurate “carbon accounting”.  For far too long the world has been inundated with partial “carbon budgets” which has allowed agenda driven activists from all sides (of the debate) to mislead at will.

The only practical way for Australia to fully sample net emissions at a continental scale (769 M ha) is via inversions, based on satellite retrievals of the column averaged dry air mole fraction of CO2 (XCO2) measured from the top of the atmosphere to the land surface. Inversion studies already published suggest Australia is currently a net sink of c.320 Mt CO2 per year – after averaging La Niña (2011) and El Niño (2017) year results and deducting fossil fuel emissions for each respective year from the total.  

Australia is the 6th largest nation in area in the world (and in the main has a land mass covered by CO2 absorbing perennial vegetation), yet it has far fewer people than live in a single world mega city (e.g. Tokyo). Yearly fossil fuel emissions from anthropogenic sources in this country {} are thus more than offset by the ongoing capacity of its LULUC&F sector (‘landscape’) to absorb them. 

Reply to  Bill Burrows
August 12, 2021 7:38 pm

I agree Bill, but the CSIRO even concedes that the entire SH is a NET co2 sink, so the clueless urgers can get stuffed as far as I’m concerned.
Of course China and developing countries will be building hundreds of coal power stns for decades into the future.
But thanks for your comment and links.

August 12, 2021 4:33 pm

Despite the fact that the Australian eastern grid is very large, covering many thousands of square kilometres, the wind patterns are larger. 

A wooden stake through the heart of the diversity fairy.

There is still pixie dust and hopium! Both are still central to the green agenda. Never let reality get in the way of a greenie!

August 12, 2021 4:52 pm

Read about “wind-droughts” in Australia and the needs from storage to manage seasonal weather variation.

August 12, 2021 5:00 pm

 It is suggested that estimates such as this should be done against a full year since there is a definite yearly pattern. By that means the low and high points of the year for wind will be included.”

As there is ABSOLUTELY no guarantee, or indeed, any accurate estimate/forecast of just what the weather will be in ANY year (or at any time), the attempts to provide energy from these ‘alternative’ sources, should stop right there.

Reply to  sturmudgeon
August 13, 2021 5:24 pm

I agree the sentence was put there because there is a definite seasonal change which can be seen in the data. We get less of solar and wind in winter. By changing the date periods one could cherry pick what I’ve done. There is nothing that decrees the wind has to blow or that you are obtaining adequate sun. I do not think coal can recover from this onslaught unless our governments decide to build them private capital is very wary as they should be. Wind will close because of lack of capital and age and it is already too late to start building. I foresee major blackouts on the eastern coast of Australia I hope I am wrong.

Geoff Sherrington
August 12, 2021 5:16 pm

About 2-3 years ago AEMO released a few reports about renewables penetration for NEM.
They inferred that 75% penetration was feasible and 95% was possible
There was a lack of clarity about drawbacks and initial assumptions by AEMO, but they are the main body on which governments rely for planning.
AEMO assumed in my reading that fossil fuels needed to be condemned with enthusiasm, so closure of a fossil generator was a benefit. This ideology shone through, but IMO was most irresponsible.
Is it possible for you to contrast your main cost estimates with those from AEMO?
It would not surprise me to see order of magnitude differences.
BTW, your report might be clearer to me at least if you explained in brief the differences between nameplate and delivered for wind and hydro. Geoff S

Reply to  Geoff Sherrington
August 12, 2021 10:17 pm

The task of what I’m doing is large. I have concentrated merely on the physical side of the generation that is wind droughts storage progress through the years et cetera. I have not done much about costs. I do however have all the data from the AEMO starting I think 2011 which does have that within it. I’m quite willing to look at the feasibility of it that it will be a lot of work I think. I have only applied simple costs such as what amount of capital is needed to supply those amounts. However if you want to contact me directly look at the help button on my webpages you will find a email address in that .

August 12, 2021 5:41 pm

Going all in for hydroelectricity in Australia simply doesn’t make sense, there just isn’t enough water. Farmers need that hydro water for irrigation. Even high rainfall Tasmania sometimes run short of water.

Rud Istvan
Reply to  Eric Worrall
August 12, 2021 5:59 pm

Eric, true. But PHES does not need much net water, only an upper and lower reservoir to contain same (less evaporation). See essay California Dreaming in ebook Blowing Smoke for the Eagle Crest California example, almost otherwise topologically ideal and pre formed.

Reply to  Rud Istvan
August 12, 2021 7:29 pm

Isn’t Australia a land of fairly frequent but irregular cycles of drought? Depending heavily on pumped water storage seems a sure route to failure, sooner or later.

Reply to  AndyHce
August 13, 2021 2:12 am

Well ideally pumped hydro only loses water via evaporation, so its not dependent on high rainfall

Reply to  Leo Smith
August 13, 2021 7:04 am

When the sun is strong and the air is dry, evaporation losses can be huge.

Chris Hanley
Reply to  Eric Worrall
August 12, 2021 6:11 pm

In 2007 drought forced Snowy Hydro to resort to coal and gas according to SMH using old aircraft engines while some electricity also supplied by off-peak pumped hydro.

Last edited 10 months ago by Chris Hanley
Reply to  Eric Worrall
August 12, 2021 9:00 pm

I am not supporting pumped hydro but it does need to be pointed out you could pump seawater it doesn’t have to be fresh water. So other than sites with freshwater supply you could use areas near the coast. No idea if it would ever be cost effective to do so but you can’t just write off ideas based on a misrepresentation.

Reply to  LdB
August 12, 2021 10:23 pm

There’s an added benefit to pumping in water from ocean – extra evaporation that might eventually come down as rain. A mode of weather and climate modification, but the salt water would kill off the natural vegetation of the upper and lower resouvoir, so a practically dead spot would be preferable. Does Australia have any large below sea-level depressions like Death Valley and the Dead Sea? Would make it easier to pump in water from the ocean.

Reply to  Eric Worrall
August 13, 2021 2:11 am

Hydrolelectric power doies not ‘use’ water that might be used for irrigation.

Reply to  Leo Smith
August 13, 2021 7:12 am

If the water is released for hydroelectric uses at a time when the farmers don’t need it, then it has used water that might have been used for irrigation.

George Meagher
August 12, 2021 6:03 pm

Sixty one billion in real money to address an imaginary problem.

August 12, 2021 7:41 pm

#1 This article refers to “energy” storage which is totally different to “electrical energy” storage.
#2 Australia is big with different climates and local resources.
Queensland doesn’t get cold in winter and they have lots of coal – no need winter heating
Tasmania doesn’t get hot in summer and they have lots of hydro – no need cooling in summer.
Victoria gets cold in winter and hot in summer and we have coal and gas- We use gas “thermal energy” for heating in winter and coal “electrical energy” for cooling in summer.

The days are short and cloudy in winter – There is NOT enough “electrical energy” available if people are forced to change from gas to electricity to warm their homes.

Reply to  waza
August 12, 2021 7:50 pm

I have worked on an infrastructure project to provide piped natural gas to the Yarra Valley.
Previously, people in the Yarra Valley used some combination of electricity, wood, or bottled gas.
The region also had a lot of commercial nurseries that used bottled gas for igloos.

Reply to  waza
August 12, 2021 10:27 pm

But that’s using common sense and logic! That’s not allowed anymore, since non-technically minded teenage dropouts control the governments of the world.

Peter D
Reply to  waza
August 13, 2021 7:58 pm

Queensland gets cold. Currently most heating is from electricity derived from coal. In Central Queensland, for some reason, wood heaters are making a comeback.
Tasmania can get warm, and the houses are not built for it. Air conditioning is widely used.
But I agree. There is no way I could generate enough energy to heat my off grid house.

August 12, 2021 10:37 pm

The 203 TWh is before electrification of vehicles etc

This would need to double is you add Trains, Plains and Automobiles

Plus all this hot water heat pumps and aircon keep this demand rising

August 12, 2021 10:37 pm

I’m definitely not a fan of RE, but for the sake of completeness solar should have been added to the mix since it produces power well for the afternoon peak, helping to reduce the draw down from the resouvoirs.

Great work however!

Any plans to extend the study to cover all of Australia, or to do continent-wide studies of Europe and North America, to see if the differences in time-zones and geographically dependent weather can reduce the amount of storage required?
I’m surprised there hasn’t been some government funded research of this type. Certainly they haven’t been shy about throwing money around and the research would likely make unreliable renewables look better and more feasible.

Joe from Perth
August 12, 2021 10:44 pm

Interesting read, thanks.

OK, let’s now increase future demand by lifting the penetration of electric vehicles. This is what many people, governments and green groups want. Cars, buses and trucks collectively take a helluva lot of energy to run. Where would they get their elecricity to recharge from? The current grid would struggle even if we retained all current generators, let alone reducing its capacity. And then there’s the issue of infrastructure e.g. the grid itself and charging stations.

Solar and wind are fine insofar as they go. But that’s not very far, and not on a grid scale. Australia needs to think about nuclear…

John Dueker
August 12, 2021 10:45 pm

“The demand for electricity on the eastern grid in 2020 was 203 TW hours, on average 23 GW hours per hour. ”

The flip flopping of units and apparent confusion of GW on instantaneous demand for electricity versus the consumption of GWH of energy gives me a headache. If that sentence said, “The electric energy consumed …. was 203 TWH.” Because dividing 203 TWH by 8760 provides zero information about the peak capacity required. Use the hourly consumption of energy as meaningful.

I agree with the article’s premise but please understand the units and how GW & GWH relate to each other.

Reply to  John Dueker
August 13, 2021 4:18 am

I agree entirely it was a mistake and I do understand quite well what you’re talking about. If you look at my demand chart will see it is in gigawatts a unit of power not a unit of energy.

Reply to  John Dueker
August 13, 2021 5:30 pm

I have approached the moderator to fix this and he has agreed.

August 13, 2021 12:22 am

Costs inevitably rise further when the batteries go up i in smoke…

August 13, 2021 1:02 am

As it stands the Australian grid storage industry is not designed in any way to replace coal plant or provide long term power…

It is doing something much more useful: providing fast response when there’s a loss of power to the grid – a powerline goes down or a power plant goes offline – and also providing a cheaper solution than peaker plants at times of peak demand.

But hey: you keep comparing apples and oranges.

Reply to  griff
August 13, 2021 1:43 am

No need storage.
We have coal.
Today east coast of Australia electricity production.
7am – coal 16.6GW, wind 2.7GW solar ZERO
12 noon – coal 12.1GW wind 2.2GW solar 6.3GW
6 pm – coal 17.6GW wind 1.9GW solar 0.3 GW

Coal with a little help from natural gas easily caters for the haphazard wind and solar.

Reply to  griff
August 13, 2021 2:14 am

Ah, the return of the Duracell bunny.

Give it up, griff. Renewables are a nice idea but they don’t work – and cheap they ain’t.

Those billions could easily be better spent

Last edited 10 months ago by fretslider
Reply to  griff
August 13, 2021 4:23 am

We have a demand pattern for electricity if it is going to work with renewables you must be able to continue to supply that demand pattern. If there is no way to do that it is a failure.

Reply to  griff
August 13, 2021 7:14 am

Batteries are so cheap compared to peaking plants, that the batteries have to be heavily subsidized.

Peta of Newark
August 13, 2021 2:52 am

It’s actually very simple for Australia.

Let the Murray-Darling Basin (re) fill with water.
The Rains will come, the weather (for most of Australia) will be nice and there will be No Need for PHES

Job done

August 13, 2021 4:25 am

Could I suggest that you edit this article to unify the way you write units. It is damned near impossible to make sense of mixing words and abbreviations in the same unit descriptor.

ie please use GWh or gigawatt.hours not GW hours is hard to make sense of.

The conclusion is that in the Australian environment on our eastern grid using wind and Pumped Hydro Energy Storage (PHES), for every TW hour 500 MW of wind and storage of 22 GW hours is needed for stability to match the existing demand pattern.

I read that five times, still could not parse it and give up reading the article, which looks like it may contain some useful info.

Reply to  Greg
August 13, 2021 5:36 pm

Let us say there is a wind station of 0.5 GW and to support that storage for 22 GWh. From that stable electricity can be dispatched of 1 TWh over a year.

August 13, 2021 5:28 am

The Gencost report was produced by the CSIRO and is IMO flawed you only need look at their assumptions for various generation types to see that they are fudging the books!

August 13, 2021 5:29 am

Dan andrOOZE and his greennutters have placed birdshredders all over west vic and on half decent farmland moving inwards too
now they need to run a massive interconnector across half the state and the landowners n farmers are mega peeved
funny thing our overpriced smartmetered system was “gold standard” OVER required capacity just a few yrs ago when we were fleeced for the cost of it
its not

August 13, 2021 10:16 am

This is all well and good – but completely irrelevant. Our politicians and bureaucrats have no interest in maintaining the present level of electricity supply- their intention is to force the people to make do with whatever they are given. Wake up people – we are drifting towards a Soviet style supply-side world !!

Reply to  Martin
August 13, 2021 6:38 pm

I do think it’s relevant. A lot of people, and even politicians, believe the simplistic analyses which are presented by ‘respectable’ organizations (including major accounting & consulting firms) which ‘prove’ that wind/solar are lower-cost than coal or gas. The analysis are based (at best) on simply dividing total costs by total kwh generated, without concern about *when* those kwh are generated and how it matches up when they are needed. When one points this out, there is generally a lot of handwaving about storage and about ‘technology improvements’. It is extremely important to reduce all this to specifics and to communicate (somehow) with people that don’t really understand energy and especially don’t understand electricity.

Reply to  David Foster
August 14, 2021 5:50 pm

There is little one can do to stop this insane rush to doom. All I am trying to do to is make more aware of what we face. The problem is this, spreading the message. Politicians I think in the future in Australia will greatly regret what they are doing. another article written by myself. We are actively destroying our electricity network on the advice of fools and here in Australia we have no way of connecting to an alternative quickly. A very prominent individual directly involved with this stated that firming as he called it would not be a problem with wind and presented a chart to show this in his extensive report. He had three days of data! For politicians to grasp the climate change meme is to grasp the poisoned chalice. It is a slow acting poison but inevitably it will destroy them all. Unfortunately much else will go with them.

August 13, 2021 3:24 pm

Are the currency numbers cited in Australian dollars?

Reply to  David Foster
August 13, 2021 5:37 pm

Yes always.

Reply to  David Foster
August 13, 2021 5:41 pm

In 2011 there was 206 TW hours dispatched on the Australian eastern grid. It was 203 TW hours in 2020. The difference is not great but in advancing economy I thought it would be going up.

Peter D
Reply to  Mike O'Ceirin
August 13, 2021 8:11 pm

My understanding the loss of manufacturing has had a big impact in electricity consumption. Planned aluminium smelter shut down in the future will have a huge impact going forward (already started in Queensland) . My understanding also is that we will just import what we need from China.
With the planned loss of coal exports, and expected loss of iron ore exports, I do not know how we will pay for any imports.

August 13, 2021 6:40 pm

There is a detailed study re what would be involved in converting the US state of Minnesota to wind/solar. I’ve only skimmed it, but it appears that the authors at least understand the issues.

Reply to  David Foster
August 15, 2021 8:43 pm

Thanks Mike and others. Very informative. From the very beginning I had the view these windmills are ugly and near useless. They clutter and destroy our unique Australian natural vista, the industrialisation of our landscape. They remind me of the HG Wells’s dead Martians in their 3 legged machines, standing erect and now useless.

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