Université Libre de Bruxelles School of Engineering researchers are investigating whether energy storage via pumped hydro systems is possible on a very small scale, particularly in buildings. The team used the Goudemand apartment building in Arras in France as their case study for Pumped Hydro Energy Storage (PHES).

So far pumped-storage hydroelectricity systems are to be found throughout the world, but always on a large scale.

Pumped Storage diagram at TVA's Racoon Mountain,s a US government organization. Image Credit: Wikipedia Commons. Click image for the largest view.

Pumped Storage diagram at TVA’s Racoon Mountain, a US government organization. Image Credit: Wikipedia Commons. Click image for the largest view.

They took advantage of the Goudemand apartment building in Arras, France that has one surprising feature. There is an open-air water tank on the roof, connected to cisterns in the building’s basement.

Using the principle of pumped hydroelectricity, these water tanks constitute a form of energy storage, unprecedented in buildings but not necessarily advantageous vis-à-vis other storage technologies.

This finding sums up the conclusion of the study conducted by Guilherme Silva and Patrick Hendrick from the ULB Brussels School of Engineering and recently published in the journal Applied Energy.

Pumping water up to a reservoir located on higher ground with a view to later releasing it to drive a turbine and produce electricity is the principle behind pumped-storage hydroelectricity production. It’s a form of energy storage to be found throughout the world.

In Belgium, for example, the Coo-Trois-Ponts power plant runs on the principle of pumped-storage hydroelectricity, and plays an important role in ensuring the nation’s energy balance and is able to reactivate the power grid in the case of a black-out. The principle of pumped-storage hydroelectricity is however little used on a small scale, as in this example, in buildings.

With this in mind, the two researchers set out to examine the feasibility and cost effectiveness of such systems. The smallest pumped-storage hydroelectricity system they found was in Greece, but it turned out to be too large to apply to a building. The two then got wind of the Goudemand apartment building in Arras, France. Managed by the regional social company “Pas-de-Calais Habitat,” the building had been recently refurbished, with solar panels and wind turbines installed on the roof. But it is its pumped-storage hydroelectricity system which makes the building unique.

After having found this rare jewel, the researchers set about studying this enormous battery: they conducted a full analysis of the building and then built a model allowing them to extrapolate the results for other similar buildings. Thanks to these simulations, the researchers realized that the economies of scale which make large pumped-storage hydroelectricity systems economically viable are not present in such small systems. Moreover, large amounts of water are necessary, requiring large and heavy facilities which are difficult to install in an urban context. Integrating such a system in a building’s water supply system is also a challenge for water quality.

As other storage options (for instance lithium-ion batteries) seem to be more cost-effective, pumped-storage hydroelectricity does not seem to be an interesting option for use in buildings. However, the researchers point to the case of buildings located for instance close to a canal, a factor which could reduce the cost of such a system. Furthermore, the full impact of such pumped-storage hydroelectricity systems (for instance on CO2 emissions) has not yet been calculated and compared to other technologies. Until then, installations such as the Goudemand residence help to pump up knowledge on the subject.

It may come as a surprise, but PHES is for now most of the world’s installed grid scale energy storage capacity. Its simple and mature technology, especially as it relies on already built reservoirs with hydro power systems installed and grid connections in place. Its works, works well and is cheap. All a facility needs is pumps and a means to keep the lower level water close by.

The ULB teams hints both in the press release and the study abstract that cutting tank requirements might get the small scale technology cost effective. A river or canal right up close would provide both the water and the low level storage. Coming up with the upper level storage and a pump and generation set also be needed.

The technology probably isn’t going to be a building option anytime soon. But the team asks a very intriguing question with hints on developing more hydro power. One doesn’t really need a dam, just a steady flow of water and enough nearby altitude for building a tank. One wonders where that idea gets economic viability. Somebody is going to be figuring that one out.


18 Comments so far

  1. Jagdish Dhall on October 27, 2016 5:23 AM

    Compressed air in an underwater balloon is the most feasible energy storage idea and should be adopted generally for wind energy. Compressed air has additional advantages in being useful for more economical pneumatic systems. Modification of wind towers for compressed air also needs consideration.

  2. Bill Pellow on May 17, 2019 1:15 PM

    I own 40 acres of forested land with a fair elevation difference of about 300 feet. I have wondered about the feasibility of digging two ponds of about 40X50 feet and about 20 feet deep, one at the top and one at the bottom with a pump and an enclosed Pelton wheel for energy storage. I have to work out the winter logistics because my outdoor temperature can reach -15 degrees F. I would like to use this for an off-grid energy storage system for my PV panels (I have about 5880 watts), but I would need a lot of advice and help. Any ideas?

  3. Mark E on June 12, 2019 4:16 AM

    Bill: The numbers on your dam I think stack up. Your 40x50x20 foot dam would hold about 1100 cubic meters of water. The elevation of that water is about 90 meters. The energy stored as gravitational potential energy is mass*height*gravity. So 1100 cubic meters is 1100,000kg x 90m x 9.81m/s2.
    This gives 971MJ (MegaJoules) of energy. This converts to kWh by dividing my 3,600,000 to give about 270 kWh. That is a lot of storage. Like the same as 27 Tesla 10kWh power walls!
    Practically you might get 70% of this but it is still huge storage. THat would give you weeks of off-grid capacity if required. Include your email if want more help mate.

  4. Mark E on June 12, 2019 4:18 AM

    Bill: contact me through my site if you want. wholehousefans.com.au

  5. Brian on June 25, 2019 7:09 PM

    I am interested in using pumped hydro storage in a suburban context . I am not a physicist or technical in anyway really, but have done some research on the tesla hydro turbine and other related things . Has anyone cracked the nut? My non technical brain says if you combine PH, with a small battery for continuity and solar for the main fill pump it might work 🙂 or is this still a dream? enjoyed the thread though guys

  6. Mark E on June 27, 2019 11:44 PM

    Hey Brian, the issue in a suburban context is that you can’t store enough water to make it worthwhile. I looked at doing this at my place with 10,000 litre water tanks. It only works if you have a large store of water like Bill Pellow above with his dam. And you also need at least 10m (30ft) of elevation from the high storage to the low storage for it to be effective. Happy to talk further. I’d love to see a small scale version of this working somewhere too mate.

  7. Matthew Y on August 19, 2019 10:04 PM

    Hi Mark,
    I have a rural property where Ive been wanting to set up a small scale pumped hydro, or at least consider it.
    I have a large river at the bottom of the property with a large supply. I have 30,000 gallons solar pumped and stored in water tanks at the top of the property which has about 50m head pressure and is about 1000ft from the river.
    Id like to created a pipeline back down towards the river and setup a pelton type micro turbine to produce some on demand power for overnight etc.
    Is it feasible? I would only really aim to run it for 3-4 hours per night.

  8. Mark E on August 20, 2019 1:59 AM

    Hi Matthew,
    You have about 55 megajoules of energy stored in those tanks. That is about 15kWh.
    TO calculate this it is just mass in kg of water (30,000*3.78) times gravity (9.81) times head height in meters (50).
    You would lose some of that energy running down the slope but assuming you got 67% efficiency that is 10kWh you would have before your tanks ran out.
    That is enough to run your power requirements at night without electric heating or airconditioning.
    Assuming you wanted to run for about 10 hours at 1.5kW you would need to size your turbine for about 3000 gallons per hour or a little over 3 litres per second.
    If you do it or want more help let me know.

  9. Mark E on August 20, 2019 2:01 AM

    Sorry Matthew for the last bit on sizing your turbine, you would get 1kW for 10 hours not 1.5kW.

  10. Phil A on December 3, 2019 5:31 AM

    I have just discovered your site and this article and thought you might be interested to know that pumped hydro can and does work on a small scale. I have about 500,000 litres of water in storage 23 metres above a micro hydro pelton wheel. The run off from the turbine runs into another reservoir where it is used to drive a water powered pump to pump it back up to the storage. A second pump is driven by a small creek all winter and when it flows after rainfall at other times. The 500k litres is used as a buffer to cope with yearly cycles, and to be used to irrigate pasture for a few sheep and 100 chickens. In the winter we get more water than necessary from the pumping and run off. The reservoir is a the key point (P A Yeomans) in a valley above our house. In a good autum and spring we about break even and in the summer we need to draw down from the reservoir which also has seepage from surroundind elevated land enough to about cover evaporation. We get approx 1 metre of rainfall yearly. Our turbine is jetted to roughly match our evening power requirements. We run it for approx 2-3hrs until we retire which tops up our sonnenschein A602/1700 series vrla (gel)cells, so that we dont get the cycling from evening activities after the sun has set. This maximizes battery life. Our first set of second hand telecom cells lasted about 15 years. Our current cells are about 8 years old. 2.2 kw of solar panels harvests the sun during the day and cloudy days are covered by running the turbine. Obviously most cloudy days are during the winter when we have plenty of water.
    Hope this is of interest.
    Phil A.

  11. Phil A on December 3, 2019 6:02 AM

    I have just discovered your site and this article and thought you might be interested to know that pumped hydro on a small scale can and does work. We have 500,000 litres of water in storage 23 metres above a micro hydro pelton wheel. The run off from the turbine goes into a second reservoir and is used to drive a pump to pump the water back up to the top reservoir. A very small seasonal creek is used to drive a second pump to also pump up to the storage. Water wise we have plenty of water in the winter, about break even in a good spring and autum and draw down the reservoir to some degree during summer.
    We run the turbine to supply the evening power requirements to minimize the battery cycling during the “peak” period. So roughly we pump up up 24 hrs to run our turbine for about 3-4 hrs. We also run the turbine on cloudy days as required, mostly in winter when water is more plentiful. Our last set of x telecom cells lasted about 15 years. We now have 24volts dc of sonnenschein A600/1700 VRLA gell cells. They are about 8 years old.
    2.2kw of solar cells harvests the sun during the day.
    The reservoir also supplies water to irrigate pasture for half a dozen sheep and 100 chickens all year round so this would be about the same amount of water that the turbine uses. I have had to set up the pump and reservoir sizes based on a yearly cycle to get it all to work satisfactorily all year round. It has been working now for several years.
    Hope this is of interest.
    Phil A

  12. Mark E on December 8, 2019 1:07 AM

    Phil, thanks so much for the info on your setup. You obviously have a lot of practical knowledge on these systems.
    What flow rate do you put through your pelton wheel?
    Mate that is just super impressive. I’d love to see some pictures of your setup.

  13. Phil A on December 12, 2019 3:08 AM

    Sorry for the double post above. Please feel free to delete one of them.
    The pelton water flow is approx 2.5 litres/second.
    The top reservoir is approx 600m metres away and 23metres above the pelton wheel. The lower reservoir is approx 100metres away and about 3metres below the pelton.
    The turbine is mostly from powerspout in new zealand.
    The pump was designed by Ralph Glockemann who has built ram type pumps in the past. This new design is not based on the ram pump principle but one of a large diaphram in the form of a tyre driving a smaller piston.They are built and marketed by Brett Porter in Qld.
    I have modified it to pump about 100% more than its rated capacity.
    About the only things I could photograph that you couldnt find on the webb is two water reservoirs in the bush and a 90mm penstock connecting them.

  14. Mark E on December 14, 2019 12:45 AM

    Hi Phil,
    I am in Brisbane – Chapel Hill. Are you in QLD?
    The Powerspout website is the spot to check if your site will work for pumped hydro.
    Thanks Phil for the reference.
    I would suggest to anyone considering this go to their website and use the calculator. It will tell you everything you need to know.

  15. Phil A on December 14, 2019 4:40 AM

    Hi Mark,
    I am in Tassy.
    I wish I had Qld rainfall here!
    Yes, the powerspout calculators are second to none. They now can wind the stators to suit your particular set up and are cheaper than you can do them yourself so are very efficient in time and money. All the information you need for the whole set up is on the site, even the manuals for all of the turbine models and the different aux equipment eg regulators etc to get everything working.

  16. Bernard on September 5, 2022 9:45 AM

    Hi Mark,
    Maybe you won’t see this. But I was wondering about the feasibility of storing say 6MW of energy in hydro systems. What’s you opinion?

  17. Beston China on November 7, 2022 8:35 PM

    It is so helpful for me.

  18. Nick on January 21, 2023 7:23 AM

    I am also interested to hear anyones idea regarding that feasibility.
    I read upping the flowrate exponatualy increases efficiency. Im looking into the option of digging or finding a big pit to create such an installation.

Name (required)

Email (required)


Speak your mind