I'm slowly gathering the parts to generate some of my own power. Have a small wind generator & plan on getting some solar panels. Plenty of sun here in the Okanagan in the summer, wind is unreliable, so hoping a hybrid wind/solar system will at least provide enough juice to run some of my tank related gear. With LED technology now to the point where we can use them to replace power hungry MH & Fluorescent lights, it's going to make it a little easier to cut down on the total power consumed by our tanks. What's been holding me up is the up front cost of solar panels, batteries, charge controllers, wiring etc to get such a system up & running. The fact that power in BC is mostly generated by hydro dams & still relatively cheap, makes it more difficult to get a return on investment on the equipment needed to get off the grid. I'm sure that will change as they inevitably continue to crank up rates.
One good thing on the horizon IMO is the switch to smart meters. It's a controversial subject at the moment with a good deal of opposition from folks who believe the signal produced by the meters is harmful and that big brother is trying to monitor what we do in our homes. It's not a concern for me. With all the other technology out there today transmitting radio signals, smart meters are a drop in the bucket in that regard. The smart meter will however, make it much easier for those who produce their own power through wind/solar/micro hydro to feed the excess back to the grid, thereby saving money. Small grid tie inverters have come down in price significantly and the technology has matured to the point where you don't need to hire an electrician & pull a permit to install the wiring to feed the grid. They're now pretty much plug & play. Take the input from your charge controller or battery bank - feed it to the inverter - the inverter plugs directly into any wall receptacle in your house - done. The inverter automatically synchronizes the power produced by your home to match grid phase & frequency. It will also shut down automatically if there's a grid outage, preventing power produced by your home system from feeding into the grid while repairs are carried out to restore power.
As far as trying to recoup a few watts from tiny turbines running off your return plumbing, not really feasible or cost effective at all. Delphinus has already hit on some of the issues & pitfalls with that approach. I've done a bit of work helping out the owner of Boulder Hut with is micro hydro generator the past two years. We just installed a new generator which has the potential of more than tripling the current provided by the original one. But we're talking a system with a significant amount of head pressure and a 2 inch supply pipe fed by a creek not far from the hut. I think the water source is about 90 feet above the generator shack, providing around 35 psi of head pressure to spin the generator pelton wheel. If you start comparing the Boulder Hut scenario to an 11 or 12 foot elevation difference for someone with a basement sump, you don't even need to do the math to realize you're not about to get much in the way of hydro power out of that. You'll be better off designing your return to feed a skimmer directly instead of using extra pumps. This way you're at least recouping some of the work your return pump is doing.
On a slightly different tangent, while researching hydro power etc, I stumbled upon something that may actually be feasible in recouping some energy from a tank return, especially a noisy one that draws some air. Do a search on the net for 'trompe' and you'll see what I'm getting at. A trompe is a way of capturing/accumulating the air drawn down with a column of water in a chamber & then using that air pressure to run air powered equipment. One of the largest versions of this is/was used at a mine in Ontario somewhere. Again, not sure whether a marine tank return could produce sufficient pressure for anything, but I'm going to do a little more research into this. Might be able to at least run an air stone for my skimmer.
FYI, here's a photo of the hydro generator at the Boulder Hut. We were unable to run it at full power since the discharge water was overfilling the storm drain box the generator is mounted on, interfering/stalling out the pelton wheel. You can see the feed valve is only about half open. At this setting we were able to get 10 amps charge current to the battery bank. The best Mark could get out of the old generator was about 3 - 4 amps. Once he gets a large enough drain pipe to handle the discharge water volume, this baby is really going to hum.
