« Back to Basics: Direct Hydropower | Main | Burning the Bones of the Earth: Lime Kilns »


Feed You can follow this conversation by subscribing to the comment feed for this post.



This is fascinating.

My first question was on the cost of municipal water versus electricity. But before I even had time to crunch a number, I realized that though I live in a rainforest, we have four-month droughts in the summer that result in water restrictions. Too many people using too little resource...

And then I realized that using the highly-filtered and chlorinated municipal water to run motors would be a travesty--maybe even worse than using it flush toilets.

So, it seems, in our current reality, that the best use of this technology you covered in your article on direct drive water power a little while ago. Of course, should our current reality change...

I am looking forward to the next article.



There's a typo in one of the highlighted quotes.

In the highlighted quote that says "At the end of the nineteenth century, water motors were also used to power electrical devices, especially radio's and light bulbs", there is an incorrectly applied apostrophe in "radio's".

Kris De Decker


Thanks, corrected.

Lisa Will


Interesting article. I live in a tropical location too. Even so, we don't have that much water to "waste" especially in urban areas where we start to face insufficient clean water.

Having said that, your earlier article piqued my interest but again, only in areas where there is large water head. Many of these are waterfalls, already where hydro electric is harvested or tourist spots. So again, little potential.

Kris De Decker


Lisa & Ruben,

Just to make this clear: the interest of this article is purely historical. I do not make a case for re-introducing water motors running on tap water, because it would be a unacceptable waste of potable water. In a forthcoming article I will investigate the future potential of the technology.



This seems to have been more of a power distribution method rather than a power generation method. The question not covered, is how does the water get pumped into the water tower in the first place? Surely some energy must have been used to put it there.

So, if this was the case, then the public use of water motors merely took the energy from the public water utility, which presumably they paid for with their taxes - but I can see the value if the public water arrived before public electric was available.

And as a practical matter today, this is still possible if you are near a water source or you can redirect a water source, Rather than have the pelton drive (or other appropriate water generator) an electrical generator, the power may be used directly instead.

The Hancock Shaker village in Hancock, MA, USA has such an example. The power was (is still) used to drive overhead shafts and power woodworking and metal working machines.



As SteveR noted, using electric pumps to raise water, only to run things with that water's potential energy is a net loss.

However, I think the small homestead or ecovillage could make use if this technology as a side-effect of their potable water use. What sort of mechanical power use is synchronous with potable water use? The very simplest might be a LED light over the kitchen sink that automagically comes on whenever you run water.

On a larger scale, how do they power all those automatic fixtures in public washrooms? I always assumed someone had to go change batteries in those things, but perhaps they're using rechargeables and water turbines.



@ StevenR

There are many ways to pump the water but steam power was widely used. Small steam engines are inefficient and a source of danger. They need a long time to heat up until they can deliver power. In a workshop or household most machines run only a few minutes every day. So steam power was not an option. Using water for power transmission allowed to have a few high power steam powerplants which where more efficient run continuously.

One point we should forget is that water is still the only efficient and economical way to store a large amount off electrical energy. Most electricity is produced by steam turbines (coal or nuclear). They run continuously but demand is not, the surplus energy during low demand time is used to pump water to a higher reservoir. With renewable energy this even becomes more important. And since there is not enough height difference in many places pressure pipes and hydraulic accumulators could become important again.

Kris De Decker


@ Jan: running water motors on water from the town mains has no future as a sustainable energy option. You can produce energy as a side-effect of potable water use, but this potential is very, very limited.

Again, this article is mainly of historical interest. Water motors were popular because electricity was not yet in use. However, the same principle could be used very advantageously in combination with renewable energy, as Matthias notes. This will be dealt with in the next articles.

Mark McClure


Hi, very interesting article.

Not to nitpick, but just to make an excellent article just a tiny bit better, there's another typo - "insure" should be "ensure."

Really appreciate your thought and hard work on this website.

Ed Smith


Given a fairly rural plot of land with a reasonable sized hill one could easily store solar or wind power by pumping water, potable or not, from a high storage tank to a low storage tank. Pumped hydro generation is done somewhere in North America on an industrial scale but what I described is strictly single home use.
Without large storage ponds I don't imagine that you could store more than an average day worth of average electrical consumption.

Gidon Gerber


Whereas "it took 7,440 litres of water to produce 1 kWh of mechanical energy", it takes 1 kWh of energy input to deliver 700 litres of tap water. So, 10.6 kWh of energy input would be needed for an output of 1 kWh.
Source: Water UK sustainability report, cited in European Parliament Library infographic libraryeuroparl.wordpress.com/2012/11/14/visualising-energy-in-everyday-items/



I think this is fascinating, and workable as a PART of a localized energy system.
I think the key to making this idea feasible is multiple reservoirs within the home, plus an external reservoir that could be pressurized, thus massively improving efficiency. For example;

1. local water supply fills a converted propane tank.
2. tank is highly pressurized by a small compressor running off solar power, accumulating pressure over time.
3. Pressurized water runs through pelton wheel connected to a generator IN THE ATTIC.
4. water accumulates in a second reservoir in the attic (or at attic height) as it leaves the pelton wheel. This reservoir has a float that engages the pelton wheel when the reservoir gets low.
5. within the house, each water using device has its own reservoir that feeds from the attic reservoir. the size of these reservoirs makes up for the slower speed of water entering the house through the pelton wheel as opposed to the standard way.

SO, when water is used, the decrease in water in the attic reservoir triggers the system, which produces electricity while refilling the reservoir. excess electricity goes to batteries, for use when the system isn't running. while the system is at rest, the solar pressure pump is still running on the exterior tank pressurizing the system for maximum efficiency.

as a part of a larger system using batteries, solar, etc., I think this could be helpful and cost effective as it could be built and maintained out of basically available local parts.

i would think one difficulty would be creating a broad but shallow attic reservoir that could be supported without major home modifications.

Mike Nomad


While it would indeed be inappropriate to use tap/potable water, there are various steps along the back side of the loop: Reclamation/Moving of Grey Water. Hard to tell if there would be a net gain even there, but, since processing is going to happen any way...



Funny that this is coming up.

I remember that some 30 years ago, a colleague working in a large IT project with a utility company in Switzerland informed me that a clause in the standard service contract expressly prohibited this usage of tap water.

I presume the small print of most service agreements with utility companies throughout Europe must have similar provisions.



@jan, there are showerheads and faucets that harness electricity to power a digital thermometer and either a red or blue LED depending on the temperature of the water.

@Matthias, hydrolic ram pumps are a technology that was used then and still is used today.... they don't produce any rotational movement, only recipicating, so they wouldn't be suited for use as a motor themselves.



LOL fun stuff,but... I'm not connected to a water grid, so it would be more efficient to use electrical power directly. The cost of any devices used to recover the flea power available from the normal household use of water would be better put towards PV & both methods would require the home be set up to use alternate electrical power. I'm in a position where I could recycle grey water, but that would entail additional plumbing and would use electrical power to to provide pressure. I have devised how I could use a water tower in freezing wether, but when all things are consider it makes more sense to keep it all below the frost line and use the electrical power todirectly to pressurize the gray water plumbing that fill the toilet tanks or operate devices as these. Respectfully this is an example how the false sense of abundance in the past got us into the shortages we have today. And we are still at giving what may be a false sense of abundance.



In reference to an earlier comment, Dominion power operates a pumped storage facility in southern Virginia (USA).




I can't find the third part of this article that's about hydraulic accumulators.

Kris De Decker


@ Ben

That's still in the making. Should be published before summer starts.



Wonderful. It's eagerly anticipated I can tell you.



Using windpumps to fill a water tower and then using water motors to provide the power when we wish to use it is certainly cleaner than using electrical batteries.



I cant still find the second part.

kris de decker


@ Mauricio: it will be published later this month.



I've been trying to find a small hydro motor that I can power with running water. I live on a hill. It would not be a problem to set up catchment at the top of the hill, use gravity feed to power the motor, and use solar to pump the water back up to the catchment. Then I would use solar power in the daytime, and Hydro power at night.



As mentioned by a previous poster, using mains water pressure to power a device is prohibited in the UK, as far as I know.



Surely it could be feasible to use a water-powered pumping device such as a hydraulic ram or a spiral water wheel pump continuously to pump water into a header tank, which could then be used to run a turbine? This would obviously necessitate a water course with a certain flow nearby, but would obviate the need for a naturally occurring header pressure.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.


Post a comment

Comments are moderated, and will not appear until the author has approved them.

Your Information

(Name is required. Email address will not be displayed with the comment.)