Engineering360: "Harnessing Hydropower"

Seriously? A water turbine installed inside the water main to extract power from excess pressure? Really?

Wouldn't simply reducing the pressure to which the water main was pumped initially have sufficed....and saved more power and money?

If I'm wrong here and they are actually getting more out than they are pumping in, then this program needs to be scaled up and expanded until those maintaining the laws of physics realize what is going on.

From what I understand, the head that they are using to drive the turbines is not pump produced head but hydrostatic (elevation induced) head. Picture a water source up on a hill feeding a town down in the valley. The flow of water by gravity to the town is what produces the energy that is either killed by pressure reducing valves or extracted by these turbines.

That seems like a hyperspecific condition for viability. How many towns are at the base of a waterfall source their water at the top of the waterfall...or similar conditions?

Try asking any experienced Renewable Energy engineer what he/she looks for first when evaluating a site for its energy generation potential and they will all give you the same answer; "evidence of a permanent water resource with a reliable historic record, of sufficient flow characteristics to exploit its kinetic energy potential using a turbine generator of some description".

In-pipe hydroelectric systems are a 'secondary use' design concept, rather than an attempt to optimize and maximise the efficiency of the 'primary use' design. It exploits the inherent inefficiencies of the 'primary use' design, and does not of course challenge any immutable laws of physics.

The combination of being able to successfully exploit gravity (free) and a water resource (free) as the main drivers for hydro generation, are the key attributes that elevate hydro power above all other forms of generation technology known today. In-pipe hydroelectric systems are an independent 'secondary use' exploitation of the 'over capacity' hydraulic component inherent (or inefficiencies) in the existing infrastructure, at no detriment to the design performance of the 'primary' system, with a resultant net gain in this overall ‘dual use’ concept.

Lawrence Coomber