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.


9 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.

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