# Small Scale Hydro-power



## Ken Scharabok (May 11, 2002)

Yesterday I had the honor of being invited to visit a under-shot waterwheel being used to grind grain in the Amish/Mennonite community south of her. Really cleaverly done. The ingenuitity of these folks continues fo amaze me.

Look for a future article in_ Countryside and Small Stock Journal_. However, at the moment I'm not quite sure how to approach the story.


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## MNBobcat (Feb 4, 2011)

Ken,

I'm a journalist as well. I live near a river. I've never measured the rate-of-flow but I'm estimating perhaps 6 mph. There is no way to get any kind of drop for a hydro system. Its pretty flat here.

So in my case, I'm interested in what the site requirements are for various kinds of hydro systems. I suspect most people who would read your story would be looking for information on how they implemented their system and what site requirements/conditions make it practical.


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## Ken Scharabok (May 11, 2002)

They have virtually no drop. Water is a spring which comes out under a limestone bluff to left of road. Goes under road to a small retention pound. Then water is diverted to an undershot waterwheel not in continuous use.

I'll post a notice if the article appears.


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## SolarGary (Sep 8, 2005)

MNBobcat said:


> Ken,
> 
> I'm a journalist as well. I live near a river. I've never measured the rate-of-flow but I'm estimating perhaps 6 mph. There is no way to get any kind of drop for a hydro system. Its pretty flat here.
> 
> So in my case, I'm interested in what the site requirements are for various kinds of hydro systems. I suspect most people who would read your story would be looking for information on how they implemented their system and what site requirements/conditions make it practical.


Have a look at this page:
http://www.builditsolar.com/Projects/Hydro/FlowOfRiver/FlowOfRiver.htm
Its on hydro for no drop streams.

If you guys find any other good projects/stories on this, or, when you get your articles published, please let me know so I can add them to the collection. Its not that easy to find good material on Flow of River Hydro.

Gary


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## springvalley (Jun 23, 2009)

I have been working on ( blueprints in my head ) overshot hydro water wheel for producing electric energy. I also have a spring fed stream that is nonstop, I have thought about damming it and making my overshot water wheel and running the shaft from it to a speed jack and then running a tractor pwered generator. I figure with the speed jack I should be able to get to the 540 rpm needed by the generator. now I know this system probably will not create enough energy for our farm , but anything is better than nothing. My prblem will be diverting a dry creek above my spring around it, so I don`t get brush and garbage that washes down it in heavy rain. I have no idea if this will work, I`m a farmer not and engineer, my wifes the electric engineer. I do believe I will have to use all ball bearings in the shafts so everything will run as fluidly as possible, so it doesn`t have anymore pull on the water wheel than needs be. Anyone that has some feed back on what they think, please tell me what your thinking and be nice, as I said I`m not an engineer. > Thanks Marc


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## machinist (Aug 3, 2010)

Hope I can help here. I am an engineer, although my life's work was machine design in the auto industry. I was recently involved in a water mill restoration here. Link: http://en.wikipedia.org/wiki/Beck's_Mill

This enlargement of the photo shows the old overshot wheel and also a turbine lower left side of the building: http://en.wikipedia.org/wiki/File:Beck's_Mill_2008.JPG Right under the "outhouse" on the corner of the building, which is the control shed for that turbine. 

The overshot wheel produces about 3 to 5 HP, from full flow out of that vertcal 8" pipe. The turbine (far left at water level) makes about 20HP, with only slightly more flow. The efficiencies are vastly different, with the overshot wheel being grossly inefficient. Forget the nostalgia of the traditional type wheel, which was based on the abilities of the early builders, and go for the modern turbine. 

I don't have flow rates of this site now, but may be able to get them. That pipe from the dam is over 20" diameter, IIRC, so judge from that. The spring that feeds it from a cave, is the drainage from about 20,000 acres. This mill ground grain for the original inhabitants here, and also did wool processing. There is a flour bolter, corn burr mills, and much more equipment inside, but most of it could only be run during the Spring rains. They also had a DC generator that provided lights for the building in later years. 

To determine your site's capability, you need data for the amount of fall available, and the flow rate. From that, it is possible to calculate tha amount of power available. It is not much for the amount of water involved. 

Example: My old homestead had a creek that drained 220 acres, and we get about 42" of rain per year. Assuming zero losses of water to evaporation and soil absorption, and 100% efficiency of all equipment (actual is far less), that site would provide about 1/4 HP for a couple weeks per year, given a dam that provided 20 feet of fall. It would have cost megabucks to build that dam, and any dam over a certain minimum is by law under control of some government agency, I was told at the time. 

The key to a good site for home water power is lots of natural fall. and continuous flow. Then, a small Pelton turbine can be used more economically. http://en.wikipedia.org/wiki/Pelton_wheel The reason being, Head (amount of fall) X Flow Rate = HP. It is usually impossible to increase the flow rate, but sometimes the Head can be increased by locating the turbine at a much lower position. The Pelton wheels are popular in mountainous territories where a comparatively small pipe, say 2" diameter, can be run downhill for a long way to gain greatly increased Head Pressure. 

I would need a lot more info to go any deeper into this.


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## Darren (May 10, 2002)

You're stuck with an undershot wheel when you don't have any drop. There was a mill here that used an undershot wheel. It could only be operated when the water was high enough. I suspect when the water was either too high or too low, the mill didn't operate. When it did, I was told they worked as long as they had water or until they were done sawing or grinding. Sometime in the early 1900s they converted the mill to run off a steam engine to eliminate the undershot wheel and it's limited usefulness in this part of the country. When the boiler blew up, as I know that was the end of the mill. Part of the boiler is still half buried along the creek bank.


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## SolarGary (Sep 8, 2005)

springvalley said:


> I have been working on ( blueprints in my head ) overshot hydro water wheel for producing electric energy. I also have a spring fed stream that is nonstop, I have thought about damming it and making my overshot water wheel and running the shaft from it to a speed jack and then running a tractor pwered generator. I figure with the speed jack I should be able to get to the 540 rpm needed by the generator. now I know this system probably will not create enough energy for our farm , but anything is better than nothing. My prblem will be diverting a dry creek above my spring around it, so I don`t get brush and garbage that washes down it in heavy rain. I have no idea if this will work, I`m a farmer not and engineer, my wifes the electric engineer. I do believe I will have to use all ball bearings in the shafts so everything will run as fluidly as possible, so it doesn`t have anymore pull on the water wheel than needs be. Anyone that has some feed back on what they think, please tell me what your thinking and be nice, as I said I`m not an engineer. > Thanks Marc



Hi,
Probably the first thing to do is to estimate how much power you might be able to generate with the flow you have -- easy to do -- all you need is the flow rate of the spring and the vertical drop you can create.

If you can manipulate the spring so that its all flowing over something you can get a bucket under, then just time how long it takes to fill a 5 gallon bucket. For example, if it fills the bucket in 1/4 minute, then you have (5 gal/0.25 min) = 20 gpm. If that method of measuring flow does not work, the link below has other methods. 
Then measure how much vertical drop you can make -- sighting along a level is one easy way to do this.

Then the power you might get with a a good generator is about:

Power in watts = (flow rate in gpm)*(Vertical drop in ft) / 8

So, if you have 50 gpm and a 10 ft drop, you might get (50)(10)/8 = 63 watts. The formula assumes that your generator is about 70% efficient.

This is 63 watts all day long, so (63 watts)(24 hr/day) = 1500 watt-hrs or 1.5 KWH a day.

If you have some drop on the property below where the spring comes out and if its descent flow, then I'd consider a small dam, then a pipe downhill to a small turbine (eg a pelton wheel) -- to me, this seems simpler and more reliable that a water wheel, gearing, ... But, either should work.

The main thing is to work out beforehand how much flow and drop you have to work with to see if its worthwhile doing anything.

This page has a lot of micro hydro how-to: http://www.builditsolar.com/Projects/Hydro/hydro.htm

Gary


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## machinist (Aug 3, 2010)

springvalley, 

You're right about the ball bearings. Plan to make the whole system run as freely as possible to reduce power losses. One of the worst offenders for power loss is the gearing or other speed changing mechanisms required. Since such a setup needs to run pretty well continuously, the mechanism must be durable, too, another plus for ball bearings. The cost of setting up a water power system makes it important to not lose any more of the output than have to. 

Overshot and undershot traditional water wheels run very low RPM's, maybe 3 RPM to 12 RPM, and generators typically want to run 1800 or 3600 RPM, requiring a terrific speed-up to work. Then, the electricity runs a motor at 1800 RPM, and you have to slow THAT down to about 100 to 200 RPM to run a 6" burr mill to grind flour. Lots of friction losses in all that gearing. It's much more efficient to gear it up ONCE from 12 RPM to 100 RPM and save all those losses--and eliminate all the other equipment. 

So, the old mills directly ran the mechanical job they set out to do, like grinding grain, or a sawmill, both of which run at comparatively slow speeds. Lots of gears means lots of power loss, no matter if you are slowing things down, or speeding them up, so match your USE of the power to the nature of your source to keep things efficient. Yeah, I know, that isn't nearly as convenient as flipping on the switch when you feel like it to run an electric motor. But alternative energy sources have these kinds of problems.

Pelton wheels, and other turbines typically run at much faster speeds, which are better suited for operating a generator. But, Pelton's want higher head pressure/lower volume than the overshot/undershot wheels. So, pick what suits your supply of water, and go from there. 

Lots of considerations here that aren't immediately obvious, since most of us are unfamiliar with the nature of water power and its' applications. One of the big ones is the high cost of STORING water power. It either takes a BIG lake, or you get to do something expensive to convert it to electricity and then stuff it in a battery bank. This leads us to consider more strongly, the immediate use of the power as Darren told about. Sort of like the old Native American saying, "Eat when there is food, sleep when there is time". So, we "grind when there is water", in this case. 

Grain grinding was probably one of the first applications of water power, because it is very energy-intensive. Even the ealry Romans had water wheels grinding grain. Today, with cheap electricity, that is no problem, but that could change instantly with a solar EMP surge. Grinding enough flour for the day's bread would immediately become a significant issue. My first crank powered grain mill convinced me of this being a problem in a world of scarce, expensive energy. To me, that makes the effort worthwhile to look at alternatives.


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## springvalley (Jun 23, 2009)

We still have two old mills standing here in our county that were used for ginding grain and flour. Both of these mills used turbine, we don`t have alot of fall here and a small dam was enough to run a turbine. A funny story I heard about the one mill, they had their own electric plant long before electric was available for rural farms. When the rural electric finally came to the farms the mill had no use for them as they already had electric. The co-op said that if they didn`t sign up for electric they would not run lines to any farms near them, well the farmers heard about this and boycoted using the mill till they signed on for electric. The farmers won, because they had no business till the electric was run to the farms, then the farmers came back to have feed ground. < Thanks Marc


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