Micro-hydro

I have a spring with a pretty strong flow although not much fall. I'm thinking of putting in a submersible water turbine just before the overflow pipe (18" diameter) empties into the creek. The spring is seldom muddy except when there's a heavy rainfall and it gets surface run-off.

I haven't measured the GPM flow yet... there is a willow tree growing just at the pipe exit. The willow has to come down because it has split up the trunk for about 8 feet and is leaning close to my bridge.

I'm thinking that I would NOT need a bank of deep cycle storage batteries for excess electricity since the spring runs 24/7... although I'm sure in late summer the flow is less. I wouldn't take my house off the grid but it would sure be nice not to pay so much for electricity.

Anyone else contemplating micro-hydro... or doing some?