Free Electricity From Water Pipes (News item).

[MarkE]

Portland gets its water from a water shed about 30 miles east of the city.  East Portland water is gravity fed.  West Portland is served by pumps.  Whatever pressure drop is imposed between the water shed and the pumps feeding West Portland is energy that must be made up by pumping against a commensurately greater pressure differential.  Where it would potentially be neutral is if it is installed in distribution branches that tie from a common point towards lower elevations on the east side.  Then it would tend to create back pressure which could actually raise pressure at the branch point and on to the west side.

[Paul-R]

Yes, some people haven't a clue. If everyone did that, then the pumping station would have to increase the pressure to keep the water flowing.

What would be clever would be to put their little turbines actually in the final tap. This would slow down and make more ordered the water as it falls to the sink or bath, this energy being wasted by ending up as noise, splashing etc.

What intrigues me is to recreate the water hammer from bad plumbing and use this for energy. I think one of John Worrel Keely's devices was effectively doing this.

[memoryman]

http://phys.org/news/2015-02-oregon-pipeline-electricity.html#ajTabs

[MarkE]

"Discussing the process, Ben Coxworth in Gizmag said, "As the water flows through, it spins four 42-inch (107-cm) turbines, each one of which is hooked up to a generator on the outside of the pipe. The presence of the turbines reportedly doesn't slow the water's flow rate significantly, so there's virtually no impact on pipeline efficiency." "

IOW, the system only converts a small percentage of the fluid power to electricity.  Most likely that makes the cost per Watt very high.

[memoryman]

I would like to see the calculations that makes it attractive financially.