Snake River, High flow rate, low velocity

Hi, I'm a contractor in Northern Idaho. I have a potential job. My client has a solar powered cabin on the snake river and wants a water generated back up. He wants the generator to be attached to his dock in some way. For those of you who aren't familar with the snake river it is a large river I've attached a photo so you have some idea with what I'm dealing with, their house has the green roof and is on the right of the photograph with a dock in front of it. Are their any systems that run efficiently off of a slow moving river? or perhaps channel down a large amount of water into fast moving water.

Thanks for your consideration

I know romans would channel the water to make a higher drop (over a water wheel instead of under) as a much more efficient energy source. I would think " they are romans and just liked to channel water" but when examining the difference in power output (although they used directly for work of turning millstones, it makes sense. I hope you get much more knowledgeable replies but off the top of my head i think making larger drop off makes sense.

In my book, Microhydro: Clean Power from Water (available from New Society Publishers at newsociety.com), I list the kinds of water sources that are more likely to be developed as microhydro sites. "Streams, creeks, springs, brooks" are small and easily controlled. Many systems use so little water that even a modest stream is plenty.

Rivers, not so much, in that they present lots of problems with flood waters and debris.

In the anthology, Serious Microhydro: Water Power Solutions from the Experts", I reprinted my favourite method of estimating water flow, which is to compare the flow of your stream with some photos I have taken over the years of the outflows of microhydro systems. The volume of these outflows is quite accurately determined by the nozzle size, and so these pictures show me in a quite precisely known volume of water. Even 500 US gallons per minute is a little stream you can step across easily, that barely goes over the toes of my gumboots, a few inches deep at most.

That said, one of our ingenious neighbours made an undershot waterwheel out of a wheel move sprinkler part. It was mightily geared up to run a truck alternator. It gave a few amps. Efficient lighting makes a few amps go a long ways.

These kind of systems work because in an off grid environment, the benefits you get from your electrical system show diminishing returns. After you have lighted the place up and charged up your phones and laptops and whatnot from a few dozen watts, it takes quite a bit more power to run electric refrigerators and freezers, like a few hundred watts. It's amazing how much can be done with so little when power is saved up in batteries and put through a modern inverter. The battery inverter subsystem makes much from little, indeed!

Anyways, I do know the Snake River and my gut feeling would be that there are probably better opportunities than that. It's not that there are potential watts there, its just that getting them out and dealing with big changes in water level will be difficult (which also means expensive).

You might need to examine just how much more power would be worth. Maybe gains can be made from more efficient appliances or design that would be the equivalent of more power.

Every site has many unique elements that need to work together to make a successful site. Wind power is quite effective at the right site. Maybe just more solar panels or a general system upgrade would meet your needs.

Really, that's what its all about is meeting needs, not generating a certain number of watts..


Cheers,

Scotty