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Pumped hydro energy storage – making better use of wind

In late September, the Australian Energy Market Operator (AEMO) released a report investigating how wind can better be integrated into the power grid. AEMO reports that as more wind turbines are deployed…

South Australia produces plenty of wind power, but it might become more than the grid can handle. Flickr/holidaypointau

In late September, the Australian Energy Market Operator (AEMO) released a report investigating how wind can better be integrated into the power grid. AEMO reports that as more wind turbines are deployed over the next seven years, constraints on the way our electricity grid works - including bottlenecks in the system - mean there may be limits on how much wind-generated electricity we can use.

AEMO has not yet investigated what long-term solutions exist to avoid curtailing wind. But a joint study by the engineering and consulting company Arup and the University of Melbourne Energy Institute is looking at one possible solution.

Electricity system operators and investors could use pumped hydro energy storage to complement the growing deployment of renewable energy. The current grid struggles to push power through when it is being generated in large quantities, and to meet demand when generation is low. Storing energy from wind using pumped hydro means the electricity wouldn’t have to be sold as it is being made, but could be saved for later.

A pumped hydro facility consists of two water reservoirs at different elevations. To store energy, water is pumped from the lower reservoir to the higher one. To generate electricity, water is returned to the lower reservoir through a turbine. This gigantic battery can be used to overcome the wind-related grid constraints AEMO identified.

In our research we have found that, for Australia, the best technology may be pumping seawater up to coastal cliff tops.

Pumped hydro is by far the most significant form of large-scale energy storage used globally. It makes up 99% of all large-scale energy storage.

Unlike conventional river or stream-fed hydroelectricity generation, it does not require a continuous supply of water. This makes pumped hydro less sensitive to drought cycles (although allowances must be made for losing water to evaporation).

Shoalhaven, Eraring Energy

In Australia, there are already large-scale pumped hydro facilities in Queensland (Wivenhoe, 500 megawatts) and New South Wales (at Tumut-3, 600 MW, and Shoalhaven, 240 MW, see image below). But no large-scale facilities have been built in Australia in the last 30 years.

All over the world in decades past, pumped hydro was built to support constantly loaded nuclear or coal generators. Today, pumped hydro is resurging overseas as it supports renewable energy sources such as tidal, solar photovoltaic, wave, and wind. Ten gigawatts of pumped hydro is under construction in China and a further ten gigawatts is under construction or being studied in Europe. The United States recently passed legislation to spur pumped hydro development.

Barriers to Australian deployment include doubts about satisfactory project economics and the perception that suitable development sites are rare.

Economic benefits

The MEI/Arup investigations found many benefits from building more pumped hydro and connecting it to the grid. It investigated locations such as far north Queensland, western Victoria, King Island, South Australia and Western Australia.

Benefits include:
- stabilising and reducing wholesale electricity prices
- increasing the spread of renewable energy - reducing the need to expand electricity transmission
- improving grid operations.

AEMO’s work found South Australia and Victoria are the states where wind generation is most likely to be curtailed by 2020 by grid restrictions. These states don’t have large-scale pumped hydro, but they could benefit from it already.

For the South Australia electricity market, we investigated the benefits of buying wind power when it’s cheap, storing it briefly in hydro, then reselling it when power is more expensive. We found that pumping from the lower dam to the higher dam for six to ten hours, holding the power for a few hours more, then releasing the water to generate electricity provided optimum financial benefits.

PHES simulation for South Australia, MEI

Where could we put pumped hydro?

But are there suitable places to cost-effectively build pumped hydro in South Australia? It’s a relatively low-rainfall state and conventional valley sites may have high conservation values.

Because of these geographical characteristics, the most-likely form of pumped hydro for South Australia are coastal cliff-top seawater facilities.

There is a facility like this - known as a “turkey-nest dam” - on the island of Okinawa, Japan: see the following image. This facility, visited by MEI, has been operating satisfactorily for over 14 years. It wasn’t originally built to store wind power, but now does.

Yanbaru Okinawa pumped hydro energy storage, Agency of Natural Resources and Energy Japan

A turkey-nest type dam can be cost-effectively built on flat ground, requiring no natural topographical depression or valley. “Turkey-nest” type dams are widely used overseas for freshwater pumped hydro. They are also commonly used in Australia for general water storage. There are many suitable coastal sites in South Australia, western Victoria, and elsewhere in Australia.

Pumped hydro energy storage could help electricity system operators and investors get more value from wind installations. Pumped hydro will also complement renewable energy as it grows. An updating of coastal cliff-top seawater “turkey-nest” technology and demonstrating it in Australia is a logical next step.

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61 Comments sorted by

  1. John Newlands

    tree changer

    No mention of cost. I suggest that stored energy retrieval retrieval should add no more than say 5-10c per kwh to generation and transmission costs. That cuts out batteries which depreciate quickly. Note King Island was on vanadium flow batteries now they are lead acid I believe and supply less than an hour's power. The clifftop tanks have the advantage of using seawater in dry coastal regions with height replacing the need for volume. However in SA you might struggle to find a cliff 100m high near…

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    1. David Jones

      Engineer

      In reply to John Newlands

      Lake Gordon stores enough energy to run all of Australia's electricity grid for about 2 weeks.
      If there was another dam as large as Lake Gordon immediately below it such that they could act as a pumped storage scheme (not possible in practice), this one scheme would be large enough to support a NEM grid which was 90% wind and solar.

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    2. Greg North

      Retired Engineer

      In reply to David Jones

      Perhaps they could look at a number of smaller storages, nest reservoirs above Lake Gordon.

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    3. David Jones

      Engineer

      In reply to Greg North

      Greg, Tasmania really does not need pumped storage, they have vast amounts of existing hydro with large storage volumes which can balance out their expanding wind generation. I just used Lake Gordon as an example because John had cited it and because it could almost have been a reality. During the Franklin dam controversy, the HEC proposed an alternative scheme, Gordon above Olga. If this dam had been built, then it could potentially have formed a pumped storage scheme in conjunction with Lake Gordon (it was only proposed as a straight hydro scheme). The potential storage would have been more than 500000 MWh.

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    4. David Bindoff

      manager

      In reply to John Newlands

      John N, I believe the batteries on King Island are ultrabatteries based on CSIRO technology using lead and carbon, they have many advantages over 'lead acid' including AGM types. The engineered life is likely to be double or more, no sulphation , high round trip efficency, high charge acceptance, virtually agnostic to partial state of charge and minimal battery management required in large strings. PbC batteries are a large step change in battery potential and can readily be manufactured on adapted conventional battery production lines. Just thought I would mention the distinction.
      Personally I would not be surprised to see this type of battery change the economics of distributed storage.

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    5. In reply to Greg North

      Comment removed by moderator.

  2. Gerard Dean

    Managing Director

    Interesting but no mention of the inefficiency of Pumped Hydro Storage due to the extra energy conversion steps required. These losses compound on each other resulting in large losses.

    Electric motors are around 95% efficient, however water pumps lose at least 20% of the mechanical energy lifting water into storage. After storage, the potential energy in the elevated water is re-converted into electricity by hydro-electric turbines which are reasonably efficient. Evaporation and seepage add another percent of two to the loss equation.

    At the minimum you will lose a third of the power you put in.

    Gerard Dean

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    1. David Jones

      Engineer

      In reply to Gerard Dean

      Modern pumped hydro systems have round trip efficiencies of better than 80%; comparable with lead acid batteries and better than such things as compressed air storage.
      For a system that is cycled daily, evaporation and leakage are virtually irrelevant.
      They also have almost unlimited lifetimes. The snowy mountains scheme (including Australia's biggest pumped hydro installation) has just had its first major overhaul after 50 years of operation.

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    2. Greg North

      Retired Engineer

      In reply to Gerard Dean

      The idea of using coastal systems and seawater removes the evaporation and seepage losses issue though it would mean that designs would need to use materials to cope with greater corrosion issues.

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    3. Jonathan Maddox
      Jonathan Maddox is a Friend of The Conversation.

      Software Engineer

      In reply to Gerard Dean

      Generating electricity from chemically stored energy in the form of coal and oxygen loses over 60% of the potential energy up the cooling towers. Even the most efficient combined-cycle gas generation loses as much as 35% of the energy consumed in waste heat.

      No energy conversion, transportation or storage technique can be or is expected to be 100% efficient. Oil refining loses 15% of the energy in crude oil. Shipping coal by rail or ship consumes more costly liquid fuels. Pumped hydro routinely achieves better than 70% round-trip efficiency. This is the technology to beat :-)

      When we're talking about using storage to mitigate losses from excess intermittent generation, remember that the alternative is curtailment. Losing some of the input power, when *all* of it is otherwise surplus to instantaneous requirements anyway, is no loss at all.

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    4. In reply to Gerard Dean

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  3. Guy Dixon

    Founder, Inventor, CEO at N.I.N.A Pty Ltd

    Moving water for urban consumption is one of the largest consumers of electricity, in some places California for example 5% of the states electricity goes to moving water. We at NINA have invented the NINA Access Pathway to harvest rainwater before it becomes contaminated through contact with road water. We then store it, in local tanks, for redistribution back to houses via the low cost NINA Access Pathway piping. This has the advantage of making urban environments far less demanding on natural…

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  4. Gary Murphy

    Independent Thinker

    The AEMO 100% renewables study investigated potential sites for pumped hydro in the NEM region. It found several sites with energy storage costs of less than $200/kWh. Unfortunately by arbitrarily limiting the generating capacity to 500MW per site it made them appear too expensive on a power storage basis.

    http://climatechange.gov.au/sites/climatechange/files/files/reducing-carbon/APPENDIX4-ROAM-report-on-pumped-storage.pdf

    My favourites are site 713 (SW of Sydney) and site 2124 (NW Tas) if Basslink was upgraded and more wind generation sited in Tasmania.

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    1. David Jones

      Engineer

      In reply to Gary Murphy

      The AEMO study was deeply flawed, mainly because it had an arbitrary limit on the size of reservoir allowed. These systems become more cost effective as the reservoir size grows, so the AEMO analysis was virtually doomed to failure.
      As an example; one of their best sites was #2878 but if a similar dam was built 10 km downstream, the stored energy would be 50 times as great for much the same cost.

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  5. Mark Lawson

    senior journalist at Australian Financial Review

    At least this article acknowledges some of the problems with wind but as the other posters have noted pumped hydro is a very expensive and not very efficient battery. Tellingly, the article does not explore costs - in fact, barely mentions them - except to say that a study on reselling gave a result which "provided optimum financial benefits". So what does that mean? Profit? Small loss? No point in even paying attention until more details are provided.

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    1. David Jones

      Engineer

      In reply to Mark Lawson

      If it was cost effective to build an installation like Wivenhoe in the 1970s to balance coal fired generation with demand; why would it not be cost effective to build the same scheme now to balance wind and solar generation with demand?
      The technology has improved quite a bit since the 1970s and pumped hydro can now be a little cheaper and much more flexible than Wivenhoe.

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    2. Mark Lawson

      senior journalist at Australian Financial Review

      In reply to David Jones

      David - if that is so, why doesn't the article say so and give some estimate of costs? But you're leaving out important considerations. Its my understanding that Wivenhoe was built in response to the 1974 Brisbane floods. Its use as as a pumped hydro facility is incidental. In fact, what pumped hydro capacity there is in Aus is from dams that are dams first and batteries second.

      However, the author is talking about building a pure pumped hydro facility, which is new to Australia, while giving only the briefest of financial details. For anything large enough to be effective the cost would be in the billions. A very first step would be ball park costs..

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    3. David Jones

      Engineer

      In reply to Mark Lawson

      Mark, Wivenhoe Dam was built as both a flood protection and water supply scheme for Brisbane but the pumped hydro scheme know as "Wivenhoe" actually pumps water between Wivenhoe and a much smaller reservoir called Splityard Creek. The smaller dam is very close to Wivenhoe and was built explicitly for pumped hydro use. Splityard Creek is a closed reservoir and has essentially no catchment. The powerhouse is built into the shoreline of Wivenhoe reservoir.

      Most of the world's pumped hydro schemes are of this type. They sensibly add a smaller reservoir in association with an existing larger reservoir which has some other main purpose. Thus the cost of one dam is eliminated.

      Australia has numerous existing hydro, irrigation and town water supply reservoirs which could be used in this way.

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    4. David Jones

      Engineer

      In reply to Mark Lawson

      Mark, the published cost of Wivenhoe pumped storage scheme when opened in 1984 was $275 Million; which should be about $700 Million in current dollars, CPI adjusted. That equates to about $1400 per kW and about $140 per kWh.

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    5. Mark Lawson

      senior journalist at Australian Financial Review

      In reply to David Jones

      David - for heaven sake go back and look at what you're written and the original article.. $275 million for the pumped hydro side of it, right... so how much did Wivenhoe itself cost? You're quoting the pumped hydro side of it in isolation in the hope that adds up to a reasonable cost. No it doesn't work that way.. You have to have the dam as well and that's the sticking point Contrary to what you say there isn't the space in dams in Aus for anything like the volumes required which is why the authors were proposing a separate, sea water facility - a point that should have been clear, and has been discussed before. For anything like enough capacity to make a dent in the requirements for wind you need serious dam space.. so it sort of works in place like Norway and Sweden storing Denmark's wind energy output but for most other places, forget it. There have been discussions about pumped storage in England where they estimate the capacity required.. not good for your argument..

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    6. David Jones

      Engineer

      In reply to Mark Lawson

      Mark, the large dams already exist. The Wivenhoe pumped storage scheme transfers water between Wivenhoe dam and Splityard Creek Dam. Splityard Creek holds only 2.5% of the volume of Wivenhoe Dam (actually about 1% if you include the flood control volume). This makes no difference to the operation of the main dam which would exist with or without the pumped hydro scheme. You could add another similar scheme to Wivenhoe if you wanted or to the nearby Somerset dam or to various other large reservoirs all over the country. The amount of water involved in the type of overnight storage envisioned by the authors is not very great.

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    7. Michael Shand

      Software Tester

      In reply to Mark Lawson

      Ahhh Mark, it doesn't matter what the plan is, unless it is coal, gas or oil he will oppose it

      Lot's of critique for renerwables, not a lot of answers, I wonder if your association with a known propaghandist outfit influences your comments?

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    8. David Jones

      Engineer

      In reply to Mark Lawson

      The UK already has at least four pumped storage schemes including one of the world's largest, Dinorwig, which was uses an old slate quarry as one of the reservoirs.
      Because of Australia's highly variable rainfall, we tend to have very large water storages which are perfect for double use in pumped storage. The UK does not have highly variable rainfall so it does not have large storages to form the basis of such schemes.

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    9. Jeremy Moon

      Engineer

      In reply to Mark Lawson

      Hi Mark, PSH's fast response puts it more in competition with OCGT which has energy generation costs of between around $150-$2000/MWh for between 50% and 1% utilisation (note that Oakey OCGT utilisation is at around 0.9% or around 3 days a year), effectively hedging against excursions up to the $13,100/MWh price cap. PSH's cost structure is similar to this depending on site selection and trading strategy, but without the fuel cost variability.

      A curious question is AEMO/ROAM's study assuming a CAPEX range for PSH of between $2000-$7000/kW installed whereas benchmarks cited (NREL & EPRI) span $1600-$4300 which obviously inflates the generation costs. Guidance I've received for our project with a net hydraulic head of around 600m is the circa $2000/kW is more appropriate.

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    10. David Jones

      Engineer

      In reply to Jeremy Moon

      Jeremy,
      if you look at Snowy Hydro's annual report for last year; you can determine that they earned $232 /MWh on average for their peaking power, via hedging contracts etc. The purchase cost of energy for storage should be only 10% of this. This should be a good guide to the economics of PSH.

      On the ROAM data: as an exercise I estimated the cost of Wivenhoe using the Norwegian Water Resources and Energy Directorate guidelines and got a cost of about $800 M against an actual CPI adjusted cost of $700 M and a cost using the ROAM technique of $5300 M.

      Good luck with your project.

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    11. Jeremy Moon

      Engineer

      In reply to David Jones

      Thanks David.

      I'm glad I'm not the only one thinking the ROAM numbers are overly inflated.

      Interesing stats on Snowy. First blush would suggest a very healthy margin if revenue is $232/MWh and generation cost is $140/MWh (I'm assuming you meant MWh and not kWh).

      AEMO data show Snowy run their TUMUT3 very differently to how CS Energy run Wivenhoe. TUMUT3 generates at near full capacity (22% c.f. 25% for 6hrs per day) while Wivenhoe runs at just 0.4%. I'm guessing Snowy is managing water and CS Energy is managing Callide.

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    12. Jonathan Maddox
      Jonathan Maddox is a Friend of The Conversation.

      Software Engineer

      In reply to Jeremy Moon

      Pumped storage made sense in the good old days (pre-2007?) when coal was so cheap to burn that it cost less to run a power station at full power overnight than to reduce its output for a few hours. This article anticipates the time that it will make sense again when solar and wind generate so much power that we can shut down the coal power stations altogether. In the meantime, storage doesn't have much of a market except on the few days of the year when other generation capacity isn't up to the…

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    13. David Jones

      Engineer

      In reply to Jonathan Maddox

      Johnathan,
      I more or less agree with your last two paragraphs and I think the advent of open cycle gas turbines using natural gas has also had a lot to do with it but your description of Tumut 3 operation is not quite right.
      Talbingo (which feeds Tumut3) is a very large reservoir but only the top few metres of water are accessible for generation. It is just an impoundment to lift the water and create a better head for generation. Jounama (below Tumut3) is actually a very small reservoir and roughly…

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  6. Andrew Gelbart

    Chemical Engineer

    This might be worth considering - a 600MWhr closed water pumping system
    http://www.youtube.com/watch?v=CujxJFXwOns from a US company called gravity power.
    http://www.gravitypower.net/
    LCOE @ $80 - 115 / MWhr which if true would compete with peaking natural gas plants. Efficiency of 75-85%
    If we were putting that price premium on say 10-15% of the energy gernerated by wind or solar, that could be viable.
    Their solution is modular so hopefully costs could come down.
    The technology is proven - They have smaller commercial scale units.
    Australia doesn't seem to be on their radar as yet. Is this an opportunity?

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    1. Fred Smith

      Electrical Engineer

      In reply to Andrew Gelbart

      Andrew, cheers for the links! That is a brilliant concept, and using the rock piston to provide the force instead of gravity sorts out a lot of the location issues. Not sure how cost effective such a system would be unless there are already existing holes from another purpose that can be modified.

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    2. Fred Smith

      Electrical Engineer

      In reply to Fred Smith

      *instead of gravity acting on water at height.
      I knew what I meant, just not clear in what I said. :)

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    3. Greg North

      Retired Engineer

      In reply to Andrew Gelbart

      They are basically applying the compressed air storage principle to water or if you wanted to use another fluid, creating a hydraulics circuit of sorts.
      " The technology is proven - They have smaller commercial scale units. "
      Don't know what the size of smaller commercial size operating units are Andrew as I could not see a reference to that on their site but anytime you start talking hydraulics, sealing becomes an issue and the bigger a cylinder and piston the more difficult it is likely to be re maintaining seals and thus reliability.
      Their system is also more for just peak loads whereas a normal pumped hydro system can and should be designed to provide for power over a longer period to cover other power fluctuations if you are to have it as part of a reliable system.

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  7. Fred Smith

    Electrical Engineer

    Thanks for the interesting article (and congratuations on your first article on TC). Feel free to jump into the comments sections as well.
    You confirmed much of what I suspected in that wind power is going to run into some serious issues from a network point of view if installed capacity greatly increases. Pumped hydro seems to be the best solution to this problem in terms of efficiency and availability, as well as giving flexibility to match generation to load curves.
    The main problem I can…

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  8. Martin Nicholson

    Energy researcher and author

    I just can't see the Greens welcoming pumped hydro with open arms - too much environmental damage. They would probably prefer energy demand reduction.

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    1. Zvyozdochka

      logged in via Twitter

      In reply to Martin Nicholson

      Martin, they are considering it. Take a look at the Gravity Power link further up posted by Andrew Gelbart.

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  9. Alex Cannara

    logged in via LinkedIn

    What lovely pictures -- reservoirs with concrete walls, impermeable liners and reversible turbines, all yielding maybe 75% efficiency and all driven by windmills of not only minute-by-minute variability, but inefficient energy extraction from the wind flowing through them and energy transmission/conversion to destinations.

    Pumped-storage systems consume land as do windmills, and worse, their reservoirs' continual draw-down/fill-up patterns exclude wildlife as well as natural shorelines..

    Wind is so inefficient that adding more environmentally-destructive construction to compensate is absurd.

    http://tinyurl.com/b7uboqe
    http://iopscience.iop.org/1748-9326/8/1/015021/ (video -- note graph axes)

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    1. Greg North

      Retired Engineer

      In reply to Alex Cannara

      In the future with limited fossil/nuclear fuels Alex, systems are going to be required or it'll be back to living without power if not in caves which all ought to be interesting if not population reducing.
      It is now and in the generations ahead that decisions will need to be made on just what the best mix of power generation can be created and to do it whilst we still have reasonably abundant fuels and resources with which to create what is best.
      So short of burning coal or running a nuclear plant and then in the absence of being able to do either, what system would you have?
      And for the masses 24/7!

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  10. Dale Bloom

    Analyst

    Instead of pumping water (which can be very inefficient), why not simply lift a large weight using hydraulics.

    For example, excess electricity could be used to power hydraulics to lift up an office tower located on pistons.

    When electricity is needed, the fluid under pressure in the pistons is used to run a turbine and generator.

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    1. Gary Murphy

      Independent Thinker

      In reply to Dale Bloom

      I have heard of schemes elevating solids mounted on rail. Haven't really looked into it though.

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    2. Robert Heal

      Botanist

      In reply to Dale Bloom

      The efficiency of hydraulics is not all that good. If you used an electrically driven hydraulic pump to lift an office building on a hydraulic ram, and then tried to extract the energy and convert it to electricity again, you'd be lucky to get a round-trip recovery of 10% of what you put in.

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    3. Dale Bloom

      Analyst

      In reply to Robert Heal

      I think 10% might be low in efficiency, but pumping water uphill is basically lifting a mass against gravity.

      So lifting a heavy object and pumping water uphill could have about the same overall efficiency.

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    4. Greg North

      Retired Engineer

      In reply to Dale Bloom

      It would certainly make working in the office interesting Dale, especially with hydraulic seal failures!

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    5. Michael Shand

      Software Tester

      In reply to Dale Bloom

      I think the basic idea is the same, other commenters have noted that it is ineffecient to use dead wieghts

      The basic idea seems the same though, water does seem like a great option but there might be other options such as using the energy to break Hydrogen from water and then using a hydrogen engine

      although I read that to get 1 unit of energy from hydrogen you need 2 units to split the hydrogen

      but hey, nothing wrong with thinking outside the box and throwing ideas against a wall to see what sticks

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    6. Dale Bloom

      Analyst

      In reply to Greg North

      It might stop office workers thinking they are too high and mighty.

      However, nothing is better than not using energy in the first place, and electricity conservation is much more efficient than generating more electricity.

      For office workers in high energy consuming glass towers, using more energy efficient materials such as “Smart Glass” seem a better proposition than generating more electricity.

      http://www.smartglass.com.au/

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  11. Greg North

    Retired Engineer

    One of the issues that will always need to be addressed with making any renewable generation into a 24/7 proposition will be the storage capacity and be it for wind or solar, having storage for a reasonably lengthy period to cover likely non generating times of the renewables.
    It will also mean that you will need a pumping and renewables generating capacity X times that of the 24/7 load to be designed for and the factor multiplication will create some enormous logistics.
    For instance with wind…

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    1. Zvyozdochka

      logged in via Twitter

      In reply to Greg North

      I'm not sure if it was your intention, but you essentially repeat the biggest myth about renewables there. "When the wind isn't blowing" etc ....

      Firstly, our electrical system is one in transition so there are (and will be) assets that can cover the gaps when the wind doesn't blown for days on end.

      Secondly, if one understands the ultimate goal-state of such a system it is possible to model and design-in a necessary mix of tech. Solar thermal w/storage and hydro storage like the Gravity Power…

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    2. Greg North

      Retired Engineer

      In reply to Zvyozdochka

      " assets that can cover the gaps when the wind doesn't blown for days on end. "
      So are you disagreeing about what you claim about myths!
      For sure, there are always going to be some places that are windier and more constantly so than others but that is not to say that every place constantly has winds or that they do not vary in strength.
      Though our electrical system is in transition, it is marginally so and in some places also marginally coping with renewables, there still being a great reliance…

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    3. Michael Shand

      Software Tester

      In reply to Zvyozdochka

      Greg did it intentionally, he is of the same ilk as Mark Lawson

      throwing up seemingly innocent comments but full well knowing their arguments don't hold any wieght

      it is about distraction and confusion

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    4. Zvyozdochka

      logged in via Twitter

      In reply to Greg North

      Sarcasim fail on my part. My use of "days on end" should have been in quotes.

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  12. Dave McRae

    logged in via Twitter

    Most informative, thanks.

    Ignore the pollutionists and science deniers as I note you have done so far. Probably because all posts like these are polluted with the same spammers with the same whinging

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  13. Bruce Miller

    Principal Consultant

    Thankyou for an interesting article - brief though it is when compared to the broadness of the topic.
    I was gratified to see that energy storage was seriously discussed at the ALL-ENERGY Exhibition and conference currently being held in Melbourne at the Exhibition centre.
    I was further pleased to see that a publicly available report "Energy Storage Options in South Australia" and can be found at http://www.renewablessa.sa.gov.au/about-us/publications-and-reports was briefly discussed in the conference…

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  14. Jonathan Maddox
    Jonathan Maddox is a Friend of The Conversation.

    Software Engineer

    Just for consideration, here are some nascent alternative techniques for storage of excess intermittent renewable energy with more modest, or different, geographical requirements, should it turn out that sufficient expansion of pumped storage is unfeasible for land-use or water management reasons.

    Adiabatic compressed air storage:

    http://www.rwe.com/web/cms/en/365478/rwe/innovation/projects-technologies/energy-storage/project-adele-adele-ing/

    Thermal heat-pump storage:

    http://www.isentropic.co.uk/our-phes-technology

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  15. Comment removed by moderator.

  16. Tim Forcey

    Energy Advisor, Melbourne Energy Institute at University of Melbourne

    Thanks to all of you that have commented on this article.

    The University of Melbourne Energy Institute (MEI) is looking at various ways to publish this research. A launch and discussion on energy storage is one possibility, similar to past public events hosted by MEI: http://www.energy.unimelb.edu.au/events

    Publication of aspects of the work via peer-reviewed journal articles is of course another option.

    MEI is interested in then taking this research "to the next stage" and is interested in discussing that with potential partners.

    Thanks again to readers of The Conversation!

    Tim Forcey, article author

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    1. In reply to Tim Forcey

      Comment removed by moderator.