You should post this in the Hot Topics forum.

All you will recover is a fraction of the energy used to pump the water into the storage tanks to supply pressure to the system.

It better be really low cost (and rugged) or it will have a payback period so long the equipment will fail before the period is over.

Brickeyee,

You got it right in the first sentence... this is stupid. It is recovering only a fraction of the energy used to pump the water.

I think what several people here are missing is the fact you are recovering energy. Recovering on something you must spend anyways, this isn't a full solution but it's a step.
chris

Enough power to keep the self flushing urinal valves charged though.

So a faucet can light up a single LED, great!

Dang! Still no free lunch.

"I think what several people here are missing is the fact you are recovering energy. Recovering on something you must spend anyways, this isn't a full solution but it's a step.
chris"

At what cost to make, install, and maintain the equipment?

Okay, if the purpose is to provide very small amounts of power to flush valves, for example - great. But that's a very limit application and that's not what is being presented in the OP.

There is no free lunch - that's not moralizing, that's physics.

If you wanted to take this idea to the next level, you could install a closed hydraulic loop through an area with pumps on the one end and generators at each home - but the amount of energy being inputted at the pump will always be more than the combined output of the generators.

An electrical grid is more efficient and flexible way to distribute electricity.

Jin Woo Han's Faucet Mini Hydro Generator
http://en.my7475.com/483.html

"The device would capture the "free" energy of your tap to spin a little generator. It can be attached to the end of your faucet or between two pipes."

I believe that is what he did say, and the amount is too miniscule to save, manage or cost to recover.

I can't believe that nobody's picked up on the fact it's NOT FREE ENERGY!

Electricity is used to pump water to consumers. Demand is created by a customer opening a tap, and by the resistance of the water flowing. In other words these mine turbines would cause resistance to the water flow (and at consumer's end, lower pressure and/or less flow) so the pumping stations would have to work harder.

It's not FREE energy. You might be regarded as stealing it, if you were, say, running your tap to generate your 'free electricity'

If the water was gravity fed, then that's another thing.

Something that would work, and ought to be considered, is storm water or sewage in hilly communities, if there's gravity-forced flow, you could generate a little power from it, in the case of sewage, you would also accelerate its treatment, as you'd be pre-aerating it.

I think the "It's not really free" part is implied by our responses.

This doesn't really shift the energy burden to the water supplier as you suggested - although you are absolutely correct that is where the energy comes from. A turbine generator on the customer's premises would restrict the flow significantly. If there's enough excess water flow that you can install a turbine and recover anything like a significant amount of energy - while still being satisfied with the water flow - then you are wasting a huge amount of water in the first place and could save far more money by reducing that waste.

"Electricity is used to pump water to consumers. Demand is created by a customer opening a tap, and by the resistance of the water flowing. In other words these mine turbines would cause resistance to the water flow (and at consumer's end, lower pressure and/or less flow) so the pumping stations would have to work harder."

You do not understand how water distribution operates.

Pumps do NOT supply tap pressure.
Tap pressure is supplied by gravity using storage tanks.

The pumps fill the tanks, and then the water level in the tank and gravity supply the operating pressure.

The turbine will decrease flow by a very small amount.
It is possible to recover some energy? Yes.
Some electronic flush valves use water pressure to extend the battery life, but they still have a battery (or use a transformer from the AC line).

The first two articles are reasonable energy recoverying technologies and are not plumbed inline in water distribution systems. They recover energy from pressure reducing vaults and valves in large systems and represent energy that would be lost anyhow. Another place they are recovering energy from is the end of pressurized purification processes. Rentricity only deals with systems with more than 1 million gallons per day and 35 psi. The SAwater article is capturing energy from water as it's moved between two storage tanks (from the purifaction facility to a final holding tank).

The tap generator is a joke and designed to separate a sucker from his money.