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100% renewables with pumped hydro would use 1/4 the water of coal and gas

Sophie Vorrath
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A 100 per cent renewables electricity grid supported by pumped hydro energy storage would not only be cheaper than the current coal and gas-based system, but would use a fraction of the Australia’s precious water resource, a leading energy researcher has said.

In a speech delivered to the APVI Asia Pacific Solar Research Conference in Melbourne this week, ANU professor Andrew Blakers said that switching to a grid powered by mostly solar PV and wind, and balanced by pumped hydro would be a water saver, and not a water consumer.

This might seem obvious when it comes to solar PV and wind energy, but what about pumped hydro?

Blakers – who is Director of the ANU Centre for Sustainable Energy Systems, is known for his view that Australia can reach 100 per cent renewables by the early 2030s, closely followed by the rest of the world.

He is also vocal about the vital role that off-river pumped hydro would play in this scenario – which has been modeled by the ANU – as a cheap, abundant and ages old technology that could balance out a grid made up of 90 per cent solar PV and wind.

Off-river pumped hydro works by storing water in an upper reservoir and running it through a turbine to a lower reservoir when electricity is needed – such as when the sun is not shining or the wind is not blowing.

The water can then be pumped back uphill when electricity from renewables and other sources is abundant and cheaper.

ANU research also led by Blakers has mapped thousands of potential pumped hydro sites around the country, and hopes to identify hundreds more, as part of an ARENA funded study.

But what about the environmental impact of building 450GWh of new, off-river pumped hydro energy storage – the amount ANU modelling suggests would be needed to support the 100 per cent renewables transition?

“A lot of people ask about environmental impact,” Blakers told the conference on Thursday. “Well, it’s minimal.

“The amount of land that we need … for up to 100 per cent renewables is about 36 square kilometres. … That’s five parts per million of the Australian continent, and vastly smaller than the largest natural lake in Australia,” he said.

“The amount of water that we need is also trivial. When you look at the water requirements you could truck it in at full commercial rates and you would not notice it in the capital cost of the reservoir.

The use of evaporation suppressors, he said, could keep evaporation below rainfall in all places in Australia.

“Importantly,” Blakers added, “if we switch to a 100 per cent renewable system supported by pumped hydro, the amount of water (used) goes down by more than a factor of four, because you get rid of the cooling towers from the coal and gas power stations.

“So going to renewables, is a water saver not a water consumer.”

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54 responses to “100% renewables with pumped hydro would use 1/4 the water of coal and gas”

  1. howardpatr Avatar
    howardpatr

    Does anyone know what Andrew Blakers thoughts are about Snowy Mountains 2 versus the development of some of the many pumped hydro sites he has identified?

    Surely the ongoing studies of the feasibility of Snowy Mountains 2 needs to be looking, in depth, at this issue?

    1. Joe Avatar
      Joe

      Feasibility of Snowy 2.0? I must have missed something. The Turnbull keeps banging on like it is already ‘lock in’ to be built. So no need for us to worry about any feasibility study, not when the Turnbull has already green lighted the thing. As for a business case? Nah, just wasting more time when nation building can get cracking.

      1. Rod Avatar
        Rod

        ABC had a snippet the other day of a company in Cooma drilling for core-samples along the new tunnel route.
        So, I think at this stage, this feasibility study has gone further than the last 4?
        The jury is out whether it will be value for money but I expect the minimum $2 billion build and $2 billion transmission might end up being a deal breaker.
        Still if NSW can blow $2 billion on sports stadiums then $4 billion is chump change.

        1. Joe Avatar
          Joe

          Hi Rod, yes I also saw that ABC piece with the core samples spread out waiting to be picked over. The Turnbull will give it quick glance over and declare…’feasibility approved, Snowy 2.0 is a build’. This business of the ‘knock ’em and rebuild em stadiums’ is bastardry government in action. The pricing tag is closer to $2.5 billions when you also factor in The Parramatta Stadium knock down and rebuild and The Parramatta Public Swimming Centre knock down…but no rebuild….just yet. Good luck to the punters living in and around Parramatta with another hot Western Sydney summer coming and no Parra Pool to cool down. The air con will be going full bore all day as the punters sit at home instead of going for a coolings off swim at Parra Pool.

    2. solarguy Avatar
      solarguy

      But are there really any studies going for Snowy 2.0?

      1. Mike Westerman Avatar
        Mike Westerman

        Quite a large team involved, with report by year’s end

    3. Cooma Doug Avatar
      Cooma Doug

      The complex water management requirements of pumped storage on the scale of Snowy 2 are already in place in the design and process of the future and the status quo. Dams dont need to be built. They are already in place. Rules dont need to be applied they are already in place.
      To provide the equivalent energy storage using other locations will struggle under the enviromental needs.

      The enviromental management requirements are not some extreme left wing nut job.
      There is a thing called “Pre SMA” on the Snowy Hydro design and management.
      What that means is that the infrastructure needs to have the ability to release and distribute the water in critical flood and dry situations that would have happenned had the scheme not been built.
      It also needs to distrubute water to the exact location and quantity it would have had the scheme not been built.

      Dont jump to conclusions when looking quickly at those words. But the infrastructure is used to protect and optimise the water systems without creating hazards or affects to the environment.

      Snowy 2 will make available hundreds of GWhrs of storage in an infrastructure envelope that protects and optimises the resources.

      The hidden difficulties waiting for thr small remote pumped hydro plans are huge. If you chop up the Snowy 2 numbers and spread them out into 50 small schemes, these hidden costs come out of the closet.
      The infrastructure requirement to spread it out to this extent is enormous.

      1. riley222 Avatar
        riley222

        Cooma,
        I saw MT on 7.30 a bit earlier, and I was hoping he’d mention Snowy 2.0, but it didn’t come up. I don’t know if you can answer this, but I was wondering how a Snowy 3.0, 4.0 or 5.0 might work , I know there was talk of being able to scale up the project , I was wondering the other day whether this could be done using existing dams. Your point about smaller schemes rings true.
        I’m hoping that MT will be in a position to give Snowy 2.0 the go ahead. If it gets the go ahead you can imagine the amount of criticism the anti renewable brigade are going to level at it.

        1. David Osmond Avatar
          David Osmond

          Some mention of Snowy 3.0 etc at the following, but like yourself I’m also interested if anyone has more info:
          http://www.smh.com.au/federal-politics/political-news/after-the-flashy-announcement-heres-whats-next-for-the-snowy-hydro-expansion-20170426-gvsil2.html

          1. riley222 Avatar
            riley222

            Thanks for the link David, if the article is correct it sounds like existing dams would be enough to cover a scaling up of the Snowy 2.0 scheme, which is a big plus.
            All up in the air at the moment, lets hope the economic argument is compelling , Oz needs this or similar projects to get going soon if we’re really going to move to renewables.
            Predictions are for electric cars to take off during the next decade as costs come down ,so there’s another reason to get going.

        2. Mike Westerman Avatar
          Mike Westerman

          There have been many variations studied over the years, but the confounding issues have been transmission constraints and compromising enviro values in the most important NP in Australia. There are some potential schemes outside the NP that could exploit the Snowy water resources/dams.

        3. Mike Shackleton Avatar
          Mike Shackleton

          The issue with continually scaling up the Snowy scheme is that we concentrate a whole heap of supply (and demand while pumping) on the network. That means scaling up the network to deal with the system running at full tilt (which may be rare) and also scaling up redundancies (which also need to be able to run at full tilt) to cope with failures. It would be a classic example of putting all our eggs in one basket.

          It is very much out of step with the distributed network line of thinking.

          1. Mike Westerman Avatar
            Mike Westerman

            Good comment Mike

          2. RobertO Avatar
            RobertO

            Hi Mike Shackelton, PHES are single units from a management point, so you pump according to what you have available (or demand). PHES can and will use coal as a part of a source of energy, but it also take some coal out of the system. I think there are about 6 coal units in NSW and Vic so a big PHES will (should) disrupt at least 2 coal power stations. Solar and wind will become the main source of energy and the coal will run flat chat to keep up with needs. This is part of the change over to RE. Gas is also part of our backup also. If Snowy is say 2500 MW and we add 2500 MW PHES then will possibly lose 2000 MW coal and as we add more Solar and Wind then the numbers may change again. Yes we need big transmission built but if we build it through a CRE zone then it has the potential to add more to the system. If the decision is made to link Tas to Vic I would prefer we did the link via King Island (KI)as you could add 1000MW wind for a costing of say extra $100 million. Robin Island would also passibly go a head. KI also uses 2.6 million litres of diesel fuel and has no fibre link (fibre costs about $600 / km if included in Power cable but $200,000 / km if laid on own.
            There is lots of right answers, but the one I support is coal has to go as a planned departure, but not as a “She will be right mate” mess.

      2. howardpatr Avatar
        howardpatr

        Thanks for the info – am still inclined to the view that the study of Snowy Mountains need to properly consider alternatives.

        It is probably a lot less expensive to build pipes above the ground and have the generating infrastructure on the surface rather than 800 metres underground.

        Wonder what thought Prof Andrew Blakers and his team have given to such issues?

        1. Mike Westerman Avatar
          Mike Westerman

          Howard – the rock provides considerable support for the pressurised waterways, so reducing the cost of steel liners. Of course if the topography allows for low pressure pipelines before dropping down to the powerhouse, this may be a cheaper option (see the Kangaroo Valley pipeline and powerhouse). These high head pumps tho’ need to be submerged quite deep to stop them cavitating – a rough guide is 20% of the pumping head, so 800m may need submergence of 160m and that means the most economic arrangement is usually an underground powerhouse with tailrace tunnel to the lower intake/outlet.

      3. Patrick Comerford Avatar
        Patrick Comerford

        An additional value in a number of PHES locations is that it diversifies the risk of having a large number of eggs (AKA Snowy 2.0) in the one basket. This risk is not insignificant think of all the possible issues that can impact a large centralized generation facility and that effect on a dependent grid system compare that against diversified de centralized equivalent facilities and you have a compelling reason for favoring the de centralized model.

        1. Mike Westerman Avatar
          Mike Westerman

          Particularly given that the SA blackout was caused by a transmission failure. Reliability 101: put the backup as close to the load as possible, with a few things as possible needing change to make it available. It’s why diesel standby sets are not considered UPS – they fail to start so often, GT’s even worse, and it’s why ultimately the secondary cause of the blackout was inadequate preparation to make sure enough backup generation was already running when the storm hit.

      4. Mike Westerman Avatar
        Mike Westerman

        Doug – say Snowy 2 is 2GW as promoted, with a round trip efficiency of 80%. That means 400MW of heat going somewhere, and a fair bit is going to end up in the water in Tantagarra. It will over time become nothing like “pre-Snowy” quite apart from the climate change stresses being imposed on the park. To say nothing also of the mixing regime for the water being cycled. These are not things you casually do in alpine water bodies.

        Several of the proposals in SA could be built very quickly – Kanmantoo for example, where Hillgrove has indicated they could start as soon as they finish mining end of next year. There are others that could be built on existing reservoirs where permitting is minimal, providing security directly onto the main 275kV grid that secures metro Adelaide and surrounds. That should be a national priority, because SA is furtherest down the road we all will have to travel, unless you are an ideological luddite lying to your constituents. I will not give the benefit of the doubt to those in authority who have so comprehensively failed to lead.

        1. Andrew Scott Avatar
          Andrew Scott

          Mike ,

          Re the 400 MW heat input,

          Do you know how the Dinorwic Pumped Hydro Plant (rated about 1700 MW) in the Snowdonia Park in Wales fares in this regard?

          1. Mike Westerman Avatar
            Mike Westerman

            Great question – it killed all the Arctic Char according to Wiki. Also the reservoirs are close together so would have similar climates. But I’ll see if I can find something on it. I’m hoping when the F’S is released it will address the thermal and intermixing issues.

      5. Andrew Scott Avatar
        Andrew Scott

        Doug,
        Mike Westerman has identified an environmental challenge posed by Snowy 2 through its introduction of heat into the Snowy Mountains Park
        – of the order of 400 MW caused by losses in the pumping/piping/generating system.

        Do you know how the Dinorwic Pumped Hydro Plant (rated about 1700 MW) in the Snowdonia Park in Wales fares in this regard?

  2. Malthus Anderson Avatar
    Malthus Anderson

    Pumped hydro needs “empty” valleys to fill. Except these valleys aren’t empty. They’re often the most productive areas left for our very threatened wildlife. So hydro storage = wildlife destruction. Not a good idea.

    1. RobertO Avatar
      RobertO

      Hi Malthus Anderson, 36 squared kilometers is tiny, and some sites already have one of the ponds there already. Some of our coal mines and the waste from burning coal (slag) would cover close to that sort of area. The Waikato River in NZ has 6 stations (8 in total) on it that are pumped hydro. The river does not have enough flow in it to cover the energy needed so it’s pumped back up the river to increase when needed. I think they use 14 MW Francis Turbines with 4 on each dam.

    2. Mike Westerman Avatar
      Mike Westerman

      Not really – typically sites are not heavily treed and developers are required to provide offsets. The biggest ongoing environmental impact is tree clearing for agriculture, many times the proposed PHES impact. Our most diverse areas environmentally are rainforests and mangroves, not at all attractive for PHES.

    3. lin Avatar
      lin

      Alternatively, you could use existing storages as pumped hydro schemes. Many of them already have generators attached. All that would be required is some below dam storage and a pump to move the water back uphill when electricity is cheap and plentiful.

    4. Andrew Scott Avatar
      Andrew Scott

      Malthus,
      No, Pumped Hydro does not need valleys to fill.

      In some cases there may be some good reasons for avoiding such sites. They are related to efficiency of pumping and turbine operations . The performance of pumps and turbines can be optimised when they are operated at constant head or near constant heads.

      The use of a deep valley storage over a ‘small area’ may result in relatively large change in water levels through the storing and discharging phases of the system cycle. Obviously this applies to both the upper storage and the lower storage.
      The combined effect of these changes in water levels may mean the pumps and turbines are required to operate across very significant ranges of head
      with attendant compromised efficiency.

      A better topography for storages consists of a large expanse of flat terrain at the upper storage (a plateau or flat topped hill or range) and use of a similar large expanse of flat terrain (or the sea) for the lower storage.
      Obviously the flat terrain has to be sealed and ringed by an impermeable bank to create the storage.
      The larger the areas employed for storage, the less is the variation in heads that the pumps and turbines have to cope with.

  3. Nick D Avatar
    Nick D

    Correct me if I am wrong but isn’t must of the hydro in NSW pumped hydro from coal power plants? I don’t see how Snowy 2 will be any different? Its excellent storage but not clean at all.

    1. David Osmond Avatar
      David Osmond

      Any form of storage is likely to charge when the price is low, and discharge when the price is high. Traditionally the price was low at night when generation was dominated by coal. That is starting to change. In SA now the price is low when it is very windy, or during the middle of the day on a sunny weekend. So going forward, batteries and pumped hydro are likely to be predominantly charged when there is a high penetration of renewables.

    2. Mike Shackleton Avatar
      Mike Shackleton

      Wind and solar is about to be rolled out in NSW on a massive scale. The pumped hydro doesn’t care where the electricity it stores comes from. The current pumped hydro facilities on the Snowy scheme may be currently used to balance loads across the 24 hour cycle, but as renewables supply increases and coal fired units are decommissioned as they reach their use by it is inevitable that solar and wind will become the source of electricity for the PHES.

      Add to that the cost of electricity produced by solar is likely to reach 2 cents/kWh. That is far cheaper than coal can be dug up for, let alone burnt and turned into electricity, even with the legacy units on the network.

  4. Ian Avatar
    Ian

    There’s 18GW of demand, judging from the live generation widget. The article talks about 100% renewables grid with PHES. 450GWH/18GW = 25Hrs storage. Is that enough? Well, you might say, it’s never cloudy and windless over the whole damn eastern seaboard, just build more wind and solar farms, beyond what’s needed , in widely diverse places and connect them up with robust interconnections and you have your 24/7 reliability. In that case is 450GWH not too much storage? We don’t want to be caught short on reliability but we also don’t want to flood our riperian environments with useless dams either. As we write, there is a pumped hydro scheme near Brisbane sitting idle, imagine hundreds of splityard creek dams on all our high ground. What, are we going to flood Maleny, or Mt Tamborine, or O’Rileys, please not Girraween National Park or the Bunya mountains. I can imagine how well the flooding of the Otways is going to go down with the people of Victoria . Travel out West there’s not much in the way of mountains, last I checked, those remote places are horrendously flat. One good place would be the top of Mount Kosciuszko, that way, one can ice skate at the top of the mountain and then ski down in winter.

    1. Ian Avatar
      Ian

      How do you say it: ‘disingenuous’, yes that’s the word. Electricity and gas used 271 GL of water in 2004/5 out of 18767GL total used. Households used 2108GL and agriculture 12191 GL http://www.abs.gov.au/AUSSTATS/[email protected]/Lookup/4610.0Main+Features12004-05

      Splityard creek dam is 105 hectares and has a storage capacity of 5000MWH. It’s unusual in that it uses a dam(Wivenhoe) that is primarily for other purposes. So for the purpose of a quick calculation: 200hectares per 5000MWH we want 450GWH PHES = 18000 hectares evaporation about 1.5m a year = 270 million cubic meters or 270 GL, mm, the headline might not be so accurate.

      1. Mike Westerman Avatar
        Mike Westerman

        Ian you write as though evaporation from a pond is additional and undesirable, but I doubt you can prove either assertion. On the other hand, having additional storage in many regions, available as a reserve, is probably desirable. On the other hand, there is little being said at the moment about the recycling challenge of large scale battery deployment, or the amount of water that mining and refining the materials for batteries, or their manufacture and recycling.

        I do agree that DSM needs to be part of the picture.

        1. Ian Avatar
          Ian

          Thank you Mike, every technology is on the table and should be considered. Water evaporation is not a small problem in this country and that was one of the objections regarding the Mary river damming project. Charts show that evaporation on our continent can go from 1 to 4 m a year. The assertion of the article is that PHES with wind and solar to supply it would use 1/4 of the water that coal and gas does. Is that true? As a prototype PHES the stockyard creek dam and Wivenhoe is not a bad example,. What is the actual water use of coal and gas and what is the water loss of PHES? For, fun you can work it out , approximately of course,but rough calcs seem to show that the difference is not that big. Either way it’s a lot of water consumed in power generation, but not nearly as much as other segments of the economy. Solar thermal would suffer the same problems of heat dissipation as coal thermal, and cooling towers seems the most effective way of creating a decent thermal gradient for turbines to work. Dry cooling is used sometimes to save water but sacrifices energy from the thermal source. These are interesting problems to be sure.

    2. Mike Westerman Avatar
      Mike Westerman

      I would be horrified if PHES is built in national parks, and it is one of my objections to Snowy 2. I agree that we need to push for as much solar, wind and DSM first, and take into account the changes that very low cost solar will bring to a host of energy consuming activities. So it will be interesting to see just how much storage is needed and the split between batteries and PHES. In SE Qld obviously at present Wivenhoe is under-utilised, but we have an investigated site at Mt Byron that can readily add another 500MW, and even Somerset could provide a small site. Near Armidale is still close enough for large scale PHES to support the export of solar from Qld to NSW or the reverse, depending on the weather, and includes Oven’s Mountain and a mod of the Apsley PHES which was rightly canned for environmental reasons but which avoids those issues. Brown Mountain has a great site outside NPs. There are sites that could use Snowy components but be constructed outside the NP as well.

      1. JonathanMaddox Avatar
        JonathanMaddox

        Snowy 2 would not involve any new dams. It would involve some new construction (penstock, turbine and generators) but the footprint of those is tiny compared with the existing water storage. Indeed most of it would be underground.

        1. Mike Westerman Avatar
          Mike Westerman

          No new dams, but an enormous amount of waste rock, new access roads during construction and mixing of biologically and thermally quite different water during operations, all for an investment of tax payers funds that can never be repaid.

          The timing of the announcement, preceded as it was by disparaging remarks about SA’s storage plans, made clear this was not a considered, planned proposal. A considered proposal would have focused on PHES in SA where the problem was palpably critical, it would have avoided an upper reservoir in a NP, it would have looked at Snowy transmission constraints first, it would have looked at the market design and why existing PHES has such low utilisation – so low that it confirms to financiers that the projects are not worth doing. Instead the support to Snowy 2 was spiteful politics, of the sort that has caused considerable damage to the industry, and may even hurt SnowyHydro in the future.

          1. RobertO Avatar
            RobertO

            Hi Mike Westerman, Until we see the feasality we do not know if its viable option (including transmission options). Currently most PHES is not utilisated is the ownership is not making enough profit (or it removes to much of the company profit). Money spent by taxpayers is often wasted, but how do you put a cost payment on community benfit. We the taxpayers are going to have to pay to save the planet from polution, companies and the government will pass the buck to us.

          2. Mike Westerman Avatar
            Mike Westerman

            RobertO, I’m a hydro engineer so solidly behind backing up our grid with PHES and going to 100% RE. But I’m also a father and a tax payer – I want my kids to have the some joy in clean air and water, and without the threat of a catastrophe, that I had as a country kid in Australia. And I know there is only going to be limited funds, particularly in these early years, to achieve what has to be done. I get angry and intolerant of fools making rash decisions for political, not reasonable ends. The unanswerable question with Snowy 2 is “where is the market for weeks or months of RE backup, especially when we haven’t yet fixed the problem of daily back up for solar?”. If you can’t get support for daily backup, then weeks’ of back up is a fool’s errand, no more investigation necessary.

          3. RobertO Avatar
            RobertO

            Hi Mike Westerman, I think of it this way, we need PHES as part of system, and short term Snowy 2 may be able to support the backup for our solar and wind. We do not have time to do a small system on Snowy 2, and then redo a larger system later. Until the feasability is completed we have no idea of what can be done, at what price and how long it’s going to take. I am sure that engineers can design a system where we overbuild (once such as penstocks) to allow the system to start small and be added to as we need more. Tranmission also may be an issue, but until we have some 50% or more of RE then storage may not be an issue. Remember Snowy 2 is a PHES system that will help kill coal, it can be used daily and it will support the change over to RE if that the way that is decided we should go, and the feasibility will show if’s worth it.

          4. Mike Westerman Avatar
            Mike Westerman

            RobertO we definitely need PHES, but not projects selected on the basis of politics. We need projects that maximise the value of RE, not that support the misinformation put around about RE and PHES. Imagine if you were a supporter of EVs and the government said they would only support the Nio EP9 – you’d be justifiably pissed off. The fact that you could go at >300kph is no advantage to you if the speed limit is 110. You don’t a feasibility study to tell you there is currently no way to get paid adequately for long term storage. Just as you don’t need a FS to tell you a supercritical coal PS won’t fly – a few scribbles on a fag packet make it clear. Instead of paying a Singaporean company $30M to redo a study from decades ago, a responsible Federal government would have funded 4-5 FS in SA to give it security of supply as it goes to 100% RE.

          5. RobertO Avatar
            RobertO

            Hi Mike Westerman, we (as in Australians) elected the idiots in Federal Government so we do have to pay the price, and $30 million is chump change to them as it’s our (Australian peoples) money. There is a lot of things that you and I would do differently, and some of them are going to cost big $. A lot of people argue that micro grids are better that interconnects, but are they the best plan for Australia. We have no plan on how to change to RE, when we should change, and what we need to change to do it? Will we need PHES to absorb solar/wind power in the middle of the day, and as you say where is the best place to put them? All part of a non existing plan. Another question that need to be asked is “how do we break the Gentailers?”

          6. Mike Westerman Avatar
            Mike Westerman

            RobertO I suspect that if Weatherall is successful in developing a GW or so of PHES in SA, he will rightfully be able to crow about his success in changing the paradigm. I’m fully behind his attempts to do so.

          7. riley222 Avatar
            riley222

            Mike the trouble is the reality of the situation is there really is no overall plan to get substantial storage into the grid. It may well be that a myriad of smaller schemes is a better way to go, but to me at the moment this seems to leave things very much to chance. Every proposal would be fought tooth and nail by the fossil fuel lobby, environmental concerns could hold things up, its just going to be a long drawn out process.
            I envisaged that if the Snowy project went ahead then solar and wind could use it to cover their storage obligations, so the cost could be spread around, and additional income obtained as a result of this service.
            Just as an aside, I wonder if Barnaby could use any spoil for his inland railway 🙂

          8. Mike Westerman Avatar
            Mike Westerman

            Riley you are right that our Fed pollies stand condemned by their lack of vision and adequate planning. But unlike you, I am more optimistic of the states getting things off the ground than the Feds – Turnbull has dashed the hopes of all rational Australians by being shown up as a very articulate paid charlatan. I am anticipating real strides forward from Weatherall before his election and from the new Qld government.

            Barnaby has shown himself to be a feather in the wind in defending the welfare of rural Australians – his greatest asset is the piles of bullshit he sprouts but I doubt it will pass muster geotechnically as suitable for a railway embankment!

          9. RobertO Avatar
            RobertO

            Hi Mike Westerman, Snowy Hydro (SH) also make money by hedging power prices so they do not have to sell any hydro to make money. Retailers buy insurance from SH so that they do not have to buy at very high wholesale prices.

          10. Mike Westerman Avatar
            Mike Westerman

            Yep – and they could do that without Tantagarra to Talbingo! They could do that with any of many of the other options available using the existing assets. Cooma Doug says Snowy 2 has the advantage of being fully permitted but I can’t see how that could be true – if round trip losses are 20% and half of them end up in the recirculated water, then that’s an enormous new heat load into a smallish upper pond in a sensitive location at a time when climate change is already threatening our snowfields. That to me is a major risk that I’m not comfortable with, quite apart from the financial illogicality of the proposal and the mendacious way it was promoted by this government.

    3. RobertO Avatar
      RobertO

      Hi Ian, you need to also work on the generating factor for the PHES. It will not be 18GW. I do not know the exact figure but if the PHES is 2500 MW then the storage will last about 9 days or so. I look at this idea as we need PHES to support RE. If this PHES is cheaper than building another site elsewhere then the storage may be an added advantage, so long as the PHES is used correctly, and not just to make money by SMC.

  5. Craig Allen Avatar
    Craig Allen

    It just occurred to me that my home town (Kimba, Eyre Peninsular, South Australia, population 600 or so) has a striking looking water tower with large water tanks around the base. https://www.google.com.au/maps/@-33.1410379,136.410305,3a,75y,47.7h,102.57t/data=!3m6!1e1!3m4!1sM_VoRnCr2yStChNB1r0FhA!2e0!7i13312!8i6656
    I wonder if a micro hydro generator attached to something like this could act as storage or at least a buffer for small scale solar generated within such a community. Kimba has suffered several blackouts in the last couple of years lasting from many hours up to several days.

    1. RobertO Avatar
      RobertO

      Hi Craig Allen, In simple terms No! Water Power = Head (Metres) * Flow (rate of Litres per sec) * Gravity (and this is watts and each has losses also).

  6. RobertO Avatar
    RobertO

    Hi All, some of the comments below have missed the point that Andrew Blakers making. Surface area of a PHES is only related to evaporation and not to power of the PHES. PHES will use less water than a coal power station, and there are ways to reduce those losses. In a mine you can seal the lining (spray on plastics or concrete). To calculate the PHES on surface area is misleading as it is volume of pond. To claim that PHES uses only coal to power pumping hence is a total loss regarding RE is misleading because as we move to RE the PHES will start to use more RE to supply energy to do the job, (and PHES will erode the coal power profits leading to the closure of coal power stations, all RE will do that also). Which PHES sites are best, I say those that have existing ponds, either top, bottom or both. Long term we will need more of them (and they need to be used, not like Wivenhoe system)

  7. James Edward Tilbrook Avatar
    James Edward Tilbrook

    Just wondering (and I may have wondered here before, I can’t remember) what people’s thoughts are on using the very large concrete water tanks that SA Water have on the (Adelaide) Hills face zone? Could they not be used as the upper storage in a PHES system to supply Adelaide? Perhaps not all of Adelaide but at least some of it or all of it for a short time. These have several hundred metres of head and the infrastructure is largely there apart from the storage at the bottom of the Hill and the generators. Someone said what about the water needs of Adelaide, how does that work if the water has been diverted to power generation use. I don’t have the answer for that but I am sure there must be a way of working it out! Also these tanks are being supplied from reservoirs and the Murray so potentially you wouldn’t need to have the lower storage, just the generators.

    Just one last thing, we are looking at a micro hydro PHES on a much smaller scale on our vineyard in the Adelaide Hills. We have a 160 kl concrete tank that has a 35 metre head above a 11 ML dam (It’s on a hill 125m from the dam). It is already connected to the pump on the dam. I’d probably have a diversion valve at the bottom connected to a turbine so we can use the same pipe to fill and empty the tank. Is there anything to consider when doing all of this and how can you work out how much power the tank can store? Also does anyone know of anyone who can supply the turbine, and give advice on the system, here in AU?

    1. RobertO Avatar
      RobertO

      Hi James Edward Tilbrook, Do you pump water from the dam to the tank. If you do then the size of the micro turbine is about 50% (or less say 25% ) of the pump. The head is small (but useable) if you have a flow rate (24 hr) of rain fall to feed the tank. Is the dam spring feed, then a hydraulic water powered pump may be able to feed the tank (about 5% of the flow, but if its rain fall then no.

    2. Mike Westerman Avatar
      Mike Westerman

      James size is the issue: the tanks may look large and the head significant, but for the MW of capacity and MWh of storage we need to think in 10s of hectares, and hundreds of meters. But the good news is that Baroota, Myponga, Kangaroo Ck, even Mt Bold at a push could potentially be used. And the other thing is surprisingly, SA has many other excellent PHES – great dam sites separated by good head differences. Anywhere else that isn’t as dry as SA, these sites would probably have been developed for water supply. But because it’s been several hundred million years since SA was wet and these gorges with rock bars and hollows 100s of meters above the plains, they’ve not been considered for holding water.

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