In-pipe energy: The hydro power nobody is talking about

Around 4% of global electricity is used for providing tap water. That number is only going to increase and its carbon emissions rival that of aviation. But a surprisingly simple idea can make our water supply more sustainable: In-pipe energy.

Credits:
Reporter: Serdar Vardar 
Camera: Killian Bayer 
Video Editor: David Jacobi 
Supervising Editor: Joanna Gottschalk, Michael Trobridge, Kiyo Dörrer

Special thanks to: Scott DeNeale

We're destroying our environment at an alarming rate. But it doesn't need to be this way. Our new channel Planet A explores the shift towards an eco-friendly world — and challenges our ideas about what dealing with climate change means. We look at the big and the small: What we can do and how the system needs to change. Every Friday we'll take a truly global look at how to get us out of this mess.

#PlanetA, #MicroHydroPower #InPipeEnergy

Read more:

"Pumped Storage and Potential Hydropower from Conduits" by U.S. Department of Energy:

On U.S. conduit hydropower capacity potential by Oak Ridge National Library:

"In-Conduit Hydropower Project" by ALDEN:

Chapters:  
0:00 Intro
1:05 Energy intensive tap water
3:27 Harvesting the excess pressure
4:22 How much energy can we get? 
7:22 Potential in the Global South
8:40 Outro

[DWPlanetA]

How could you make a use of in-pipe turbines?

[LouSchonder]

I'm stuck on the issue that if the flow is tapped, it will require more pressure to maintain the original flow rate. It seems apparent that there must be a lot of wasted energy generating the water pressure to make this viable. Tapping anything other than that will reduce system performance.

[heliobarcelos]

I'm a student and technician in renewable energy, and a similar idea had already occurred to me, I researched it and went to calculate it on paper (on a different scale than the video). Among the results, I came to the conclusion that a high pressure generates little energy, the yield would be low, and would demand more energy in the pressure pump that sends the water. For few people to generate energy to charge their cell phone at the beginning of the distribution line is feasible, but scaling it is complicated. There are several factors that influence performance, the water flow has to be very large for generation if relevant (among others), that's why hydroelectrics are good, but when water is pumped by electricity and you put an electric generator at the end, the gain is low, if it were so simple there would be infinite generators, but the laws of physics do not allow it. In my calculations, for example, approximately 5000 liters at an average height of 5 meters, would be able to generate the equivalent of 15 minutes of energy that a gasoline generator can, and with a submerged pump and that same generator it took me 1 hour and a half to fill that container. Notice how low the gain is. I love the videos on this channel, I loved the space for reflection on this, because I also thought, researched and calculated about this idea, on a different scale from the way it was presented. The idea does not seem to me to be efficient. However, this does not mean that the idea is not good, we should think more and develop ways to make ideas like this workable.

[xfiles]

I submitted this concept to Popular Mechanics in the 1990s and all I got was a T-shirt.

[ascienceguy-]

My city, near Denver, receives its water from high in the Rocky Mountains and all water is moved by gravity. Pressure in the large raw water pipes is dissipated at treatment plants by hydroelectric turbines, which earn about 2 million USD per year sold at wholesale prices to the regional power provider-- so the concept is proven. However pressure in the treated water pipelines is dissipated with small turbines and those barely pay for installation costs and maintenance. I can not imagine tiny turbines in the pipes of my home would be worth the effort.

[makemineapint]

Rather than complicating the infrastructure further, isn't the solution to manage the pressures more effectively so you use less energy? It strikes me as a solution for a problem that shouldn't exist. Sure if you've got a high head source, extract the energy, but if you have pressure reducers working overtime, reduce the power input at the pumping source, far more efficient. Ok, Water utilities need to invest in decent telemetry to monitor pressure and flow rates but the benefits in energy saving and the ability to spot leakage issues and reduce waste would be every bit as useful.

[kepplergaus]

This video has multiple issues in my opinion. We need to talk about the amount of energy that can be harvested from pipes.

For all cities that need pumps to distribute water, you cannot harvest more energy than the pumps have put in - otherwise you would create a perpetuum mobile. Sure, we can harvest some of the excess energy during reduction of pressure. But when you say we can power a city from the pressure in its water pipes, that is just wrong, as we can never harvest more than the roughly 4% of total energy consumption that we put into the water system, as you claim.

For a typical household that we can assume uses 500 liters of water a day (some 180 m³ per year), and "wastes" 3 bar of water pressure, which are rather high assumptions to me, that means a potential energy of 500 kg * 30 m * g = 150 kJ per day. That is 41 Wh per day. Yes, you can charge a few phones with that, but that's not even 1% of a typical households energy consumption.

Regarding the second report at 4:55, you got the units wrong. The report is much less optimistic than the one before. The report says we can harvest an energy of 43 GWh/a (Gigawatt hours per year), not a continuous power of 43 Gigawatt. Converting to power, this is only 5 MW (Megawatt) of continuous power. Enough to power 5000 households, but not 43 million of them.

So sure, build some turbines in places where pressure regulation valves reduce pressure strongly. But this is not the solution for making lots of clean energy.

[iuliuscaesar]

So since you propose to fine-tune the entire system by adding turbines instead of valves (assuming I understood the theory right), why not just make the whole system more efficient at delivering the exact pressure required, since it really seems the cheapest solution. Adding turbines instead of valves will surely add maintenance costs on top of longer or shorter periods of time when the turbines are useless. Adding them will likely also motivate to adjust pressure before them (perhaps) just to reduce their uselessness. Better fix the system while this actions is still cheap and less complicated.

[jasont]

This would only be useful in places where the water is traveling by gravity alone. Otherwise, you are just generating power by removing flow rate created by other electric pumps.

[lil----lil]

Any mechanical resistant met will cost energy no matter how small. PERIOD. This is indeed, a pipe dream.

[mojtabaeisakhani]

Thank you, it seems that this type of energy production is ideal for areas that water moves in the pipes freely because of a gradient, for example from high hills to low hills. Extracting energy from water that is pushed in the pipes by a pump is waste of energy.

[stevemann]

I’m a plumber, and that is a great idea. Every house should have one right after the water meter

[anguscampbell]

Recycling grey water from domestic showers, clothes washing and dishwashing into toilets for flushing would reduce water usage by about 1/3 along with the energy required to treat, pump and dispose of that water.
This is something than needs to be done.

[ktktktktktktkt]

4:30 1.41 jigawatts? That's more than enough to travel back to the future.

[samuxan]

Almost ten years ago I wrote a paper on energy generation with microturbines in certain sewage systems. The thing with drinking water is that the sanitary conditions needed make it harder, but with sewage or irrigation systems regulation is lighter and implementation becomes easeir

[rocketman]

Yes, this is exactly how I generate my own electricity.
With an in pipe generator that provides the electricity to pump the water through a pipe in a circular layout.
That then in turn drives the in pipe generator in the circular pipe layout to make even more electricity.
I just have to be careful to avoid runaway energy building up in the system or it bursts the pipe.
So I have had to install an over pressure relief valve and a safety trip switch to prevent excess electric current from burning out the pump motor.
Hehe...
:^ )


There's a reason why nobody's talking about it.

[oneordinarycitizen]

A pressure reducing valve (pressure regulator) does not "waste energy" as stated at 2:35. If it did, heat would be generated because the energy must go somewhere. Large water systems have excess capacity to ensure good performance even when there is maximum demand. Adding turbines to a water system will remove energy and cause the pumps to work harder to maintain water pressure and flow rate.

[Petch]

I would have liked a better explanation on how and how much energy we waste when changing the pressure. To me the looks to be two problems. 1 you need to make sure that you are not just adding more resistance in the system so that you increase the energy needed to pump the water. 2. It looks to me that it is not that much energy you can recoup and it might be cheaper to just build solar or wind.
In general I prefer minimizing energy losses over recouping energy, cause you just add one more step where you also lose energy.

[mikerothmusic]

Your videos are great! One thing though - you consistently use the terms for power and energy incorrectly. When you are talking about power the units are in W, MW, GW, etc. This is used for a the installed capacity of power plants or the amount electricity a lightbulb uses (1 watt = 1 joule per second...the rate at which work is done). Over time, like the course of a year, energy should be used. Energy is the "ability to do work" or how much work has been done...it is measured in kWh, kWh, GWh, TWh, etc... At 5:00 you don't say 43 GW of energy per year could be harvested...it is incorrect. The paper uses energy terms here not power.

[karlomoharic]

2:42 Not a pressure valve, just regular valve

Also there is this thing called second law of thermodynamics, which basically tells you that most of realworld enery processes are not reversible, therefore you are justgoing to end up wasting more electrical enery with this system . If you wish to consereve energy in regards to water distribution, just use water towers.