Generating Electricity from a River

You could probibly use some sort of turbine, maybe similar to a wind turbine. As your flows are pretty gentle, you wouldnt get much velocity in your turbine, but if you had enough surface area you could get a fair bit of torque, enough to turn a big gear maybe, then could have a chain drive to a dynamo or something to generate the power. The amount of power you would get would be dependant on the size differental between the drive gear and the gear on the alternator (assuming the turbine will turn the gear).

You won't have too much problem with iceburgs in the future, unless a whole heap of your country men follow your lead.

This is a poorman's technology in the foot hills of Himalays in North India. People use water flow to power small mechanical wheel and use the power for electricity and grinding the grains. Just visit the zone and you can see for yourself and can learn to build such things for about US$1000-5000 range. Some people also build such devices near river banks. Some how you need to place a water driven mechnism in the river and carry the energy to your backyard.

I love the iceberg comment! For that matter, it will not be long before the requirement for heat is reduced too.

Actually, I think you will find that heating the house would require a very large generator/alternator. Often, people in your situation will use a generator to charge batteries, and then run loads through an inverter, which provides a stable sorce of ac at the right voltage and frequency. There are many alternatives available for generators, as other posters have suggested. At that stream flow rate, a trolling motor would make a pretty good generator, given the right prop. (You'd need several to make a large dent on your electrical bill, though.) If I recall, a small trolling motor is about 400 watts, which would translate to roughly 4 cents worth of electricity per hour... which doesn't sound like a lot. But that's about a dollar a day, $365 per year. Suppose you found a cheap source for a bunch of trolling motors?

Your One Pod may get 300 mpg but can it do wheel standing wheelies!

The simpliest solution for you can be vertical axis turbine created from one 20'' pipe and two circle shimms. Diameter of the pipe must be 0,6 of the rings (shimms) diameter. Cut the pipe axially creating two half-moon cross section elements (lenght should be like your river deepness). Weld the shimms with the two pipe parts - like this " _{( ^{) "} just by this way.}

_{install it using shaft and bearings inside the water (vertically) ,dynamo and all mechanic accesories - bearings, torque converting tools etc should be above the water.}

_{It is very easy turbine but any way need precisious performance (balancig and common axis of all rotary elements)}

_{There is no chipper solution}

Sailors use towed generators behind their boats operating at speeds of 5-7 kn. I would think that a towed generator anchored to the end of your dock in 4-5 mph stream would work as well especially since it would be 24/7. The units are small enough to be easily removed when iceflows challenge.

Check out "Windstream Power Systems." They may have exactly what you need. they can definately point you in the right direction. You'll probably end up having to produce DC power with battery storage, then run it through a power inverter. I doubt you'll want to invest the money it will take to power your entire home (especially the heat.) I'm sure you could probably easily power a few lighting circuts.

What's wrong with an old-fashioned undershot waterwheel? They're cheap to build. Torque is a function of the wheel diameter; speed is a function of the river flow rate, and each has a factor thrown in for wheel (turbine blade) characteristics, and power is a function of torque and speed. Since the flow of the river is more or less constant, the speed can be geared up to run an ordinary AC generator. Most appliances and all incandescent lightbulbs and resistance heaters don't mind if the frequency or voltage fluctuates 5 %.

Take it out in the winter or rebuild it, if needed, each spring.

There were forty thousand waterwheels in Europe from the middle ages through the Renaissance.

There are several ways to harnes the river flow, small above the water turbine spinning a three phase generator, which in turn can be amplified through a transformer that can power a larger system. The larger you wheel, the more energy that can be produced. So, if you set up a flow system with four drive wheels, having three-3phase generators in line, you could have enough usable power to actually be boosted through a transformer to feed your needs.

To gaurantee this output, It would be worthy to set this wheel system up on to a geared driven transfer to give you the correct frequency of ~60hz for your output. The output would need to be run through a rectifier for your AC output.

But beware of the power regulation commission that controls who can set up a power grid in their yard. I know for a fact that out here in the west, private residents are not allowed to setup any type of self relience system on their property. We had an individual set up a wind mill and was generating enough power to feed a 5 mile radius out from this self sufficient system. The local power company had the state pass a regulation law that outlawed privateering of power producing systems as an alternative source of energy. Since then, thay have had to disassemble this windmill after ten years of court battles against the power regulation commission.

Now to beat this problem, you would actually have to go through the legal system and incorporate a non-proffit entity as a research facility in the study of alternative power generation systems. Then you could actually quallify for government grants that are available for minority businesses. So, set up a board of directors of women of verious nationalities to pull off this heist of actually putting our tax dollars to work where it belongs. Back into your community. How about them apples to feed on?

I like the sound of that! My best case scenario would be to have no one from any government agency knowing anything about my little experiment, I just want to try it without all the red tape; not very likely though. The best idea would be far enough under water that it would not be noticed. I really like the idea of making the government pay for it though, then maybe, I would have the DNR and the zoning people on my side.

Your quest for an underwater mill is not really feasable with your available resources.

The current flow only being around 5mph is barely enough to turn a water mill. I am not sure how a turbine would work for your power needs. Even if the current was at constant known value, your turbine would need to have a diameter greater then 30". The turbine would require to be set up as a 3-phase out put, ( that would be nine sets of magnetic pick-ups) and would require a rotation speed of ~60Hz constant. Only way to actually achieve this rotational speed, is to design a geared tranfer box that would be capable of using your 5 mph of water flow. Not enough flow rate.

I would like to know which state that was. The trend has actually been the other way around, starting in the 1970's, during the so-called "energy crisis" with states passing laws to enable homeowners and small businesses which generated their own electric power to sell excess power back to the grid, albeit at discounted "wholesale" rates rather than the normal "retail" rate which they would have to pay for any power the drew from the grid when their own needs exceeded their capacity. Also, the "Quality" of the power would have to meet grid standards, as it would be for any commercial plant supplying power, i.e. the voltage and frequency would have to remain fairly constant. Frequency (60 Hz) is particularly crucial, since many devices (clocks in particular) rely on its accuracy. It is so important that even the power companies have equipment to regulate the frequency, including increasing or decreasing the frequency temporarily so that the accumulated average will be exactly 60 Hz.

The problem was/is in most states, purchase and operating costs of small alternative energy systems was so high as to make their operation unfeasible in economic terms solely as a replacement for commercial power. The initial high investment with long-term payback makes other investment opportunities more lucrative.

If you can build something yourself at low cost and use it solely for your own usage, i.e. keep it isolated from the grid, it may be more cost effective. But you may find the results disappointing, particularly if you want to use it as the major source of heating energy. Is the location rural, urban, or suburban? If rural, and you have the ability to cut and stack firewood freely, a wood-burning furnace may be your best alternative for primary heat, supplemented by a buried heat-exchanger based electric heat-pump system, not in-efficient "resistive heating" systems like portable electric heaters and base-board heaters. Heat pumps actually produce more energy than they use because they remove heat with a heat exchanger from colder areas (like underground, below the frost line) and literally "pump" it into your house, rather than creating heat directly from electricity as resistive systems do.

As for your "River Energy" system, be careful of the comments regarding "water wheels". Sure, they were prevalent for hundreds of years, in both Europe and North America, and still work in some parts of the world. When you have no alternative, low-tech water power can supply some of the needs. In most cases these were/are only effective where there is sufficient velocity in the stream itself, or the water can be restrained in a "mill-pond" with a dam, then allowed to flow-out via a narrow "mill-race" which concentrates the stream to a fast-flowing channel to turn the wheel with sufficient force and speed. Bear in mind also, that most of the energy needs which these mills supplied was strictly mechanical, powering "millstones" to grind grains into flour, or belt-driven machinery used in textile "mills". Conversion of mechanical energy to electrical energy can be very in-efficient, particularly if storage is necessary for peaks in demand that outstrip production. You may also find that the size of such a system to meet your power demand is extremely large, which may itself be problematic.

Removable turbo-generators may be a solution, but beware of high acquisition and installation costs. Like many gasoline/diesel driven generators, they will have significant maintenance costs if used for more than emergency backup. Be sure to complete a very thorough cost/benefits analysis and ask the equipment suppliers for references from other customers in your locality. They should be able to provide real data to use in your analysis. Surely, you are not the first ones to think of using River Energy in your area!

An alternative, especially for heating, might be to use the river water as a heat source for your heat pump system. Heat pumps are more efficient if the heat exchangers are constantly in contact with a conductive material which is at a higher temperature than the outside air. That is why they are often buried below the frost-line, which stays around 50-60 degrees year round despite colder air temperatures. However shallow-buried heat exchangers can be made more efficient if they have a replenishing source of moderate temperature heat, like well-water. River water may provide an even warmer source of heat, especially since it is an effective solar collector! You may not want to swim in the river in winter, but it may be warm enough (way below the ice anyway) to help your heat pump be more efficient.

Not to discourage you from investigating the exploitation of your natural resources, but be careful not to wind up with a boondogle that costs more than it produces.

"The trend has actually been the other way around, starting in the 1970's, during the so-called "energy crisis" with states passing laws to enable homeowners and small businesses which generated their own electric power to sell excess power back to the grid, albeit at discounted "wholesale" rates rather than the normal "retail" rate which they would have to pay for any power the drew from the grid when their own needs exceeded their capacity."

Yep. The power companies got their way by requiring that anyone wanting to connect to their grid had to purchase connection/regulation equipment from the power company and had to pay maintenance fees to them.

"As for your "River Energy" system, be careful of the comments regarding "water wheels"."

You didn't mention why to be careful . . . It's pretty doggone inexpensive to build and operate compared to more elegant systems. If speed regulation is a concern (because stream velocity changes more than a little), manually or automatically controlled variable pulleys are reltively inexpensive also. It's not required that you synchronize to the power coming into the house: It's only necessary to isolate circuits which aren't critical to life from those which are to take advantage of "river power."

Remember, "There's No Such Thing As a Free Lunch!" But that doesn't mean you can't get a cheap one! It's very easy to spend more to utilize river power than you will ever recover from it.

Bill said, "You didn't mention why to be careful . . . "

Well, yes, I did, if you read the rest of the paragraph, but, let's see. Maybe you have provided some of the answers to that question yourself.....

"Take it [undershot waterwheel] out in the winter or rebuild it, if necessary, each spring". Hmmm, for as large as some of these mills are, you better have a whole crew of free labor, or access to free power equipment, or both! Rebuilding can be expensive, also, unless you have the necessary skills personally to handle the job! I also found this at www.whitemill.org:

"In areas with no slope of any kind to speak of, such as we find at Whitemill, the only choice is the undershot waterwheel. Compared with the other types this is horribly inefficient. Here the wheel relies on huge quantities of water, moving at considerable speed, to drive the mill. Such mills are usually built on substantial rivers - streams just don't have enough water. Typically, a percentage of the water in the river is diverted along a leat to the mill. Undershot wheels are normally quite narrow and have to fit very accurately within their channel to prevent the water from escaping round the sides."

Bill also said, "If speed regulation is a concern (because stream velocity changes more than a little), manually or automatically controlled variable pulleys are reltively inexpensive also."

Perhaps to buy, as components, initially, but to install, unless one can do that kind of work oneself, it might be very costly.

"It's not required that you synchronize to the power coming into the house: It's only necessary to isolate circuits which aren't critical to life from those which are to take advantage of "river power.""

If one was building a new house, I might, partially, agree. But retrofitting an older house for dual power, unless you are an electrician yourself, or you ignore codes, could be very costly. Then you have to say, well, what do I do if the secondary (river energy) system fails? Remember, the original question was to generate power for heating, which, to my mind, would be "critical to life". I guess you would have to re-design your power system for redundancy and quick switch over with equal capacity, which could be even more costly.

"Remember, "There's No Such Thing As a Free Lunch!" But that doesn't mean you can't get a cheap one! It's very easy to spend more to utilize river power than you will ever recover from it."

TANSTAAFL! Exactly, that was one of my main caveats. I did not say DON'T DO IT. I just said "Be careful". And a modern turbo-generator, while perhaps having an initial high cost, is likely to be much more efficient, smaller and easier to handle, lower lifetime ownership costs for periodic maintenance and unscheduled down-time, than the so-called, "low cost, low-tech" approach, which depends on the owner to be very skilled in many disciplines and crafts to build and maintain it, otherwise he WILL be paying others, if he doesn't abandon it out of frustration! Talk about "Sunk costs"! (grin)

I think heat pump is the way to go. If you have a lot of area available a pretty neat way of artificially heating an area that you can in turn use the power is with a green house. Even in the middle if winter, there is energy produced by sun light especially under glass.

"... spinning a three phase generator, which in turn can be amplified through a transformer that can power a larger system."

"... you could have enough usable power to actually be boosted through a transformer to feed your needs."

Please explain how a transformer will amplify power in the application you describe.

"To gaurantee this output, It would be worthy to set this wheel system up on to a geared driven transfer to give you the correct frequency of ~60hz for your output. The output would need to be run through a rectifier for your AC output."

I'm afraid you lost me again.

It all sounds technically wrong, and somewhat bizarre. What area and state "out here in the west" are you talking about, and what law?

Greg

Thanks for all the input. So far the water wheel with a mill pond and mill race sounds like the best idea. Could I start with a small one, around 36" diameter, somewhat of a small prototype model that will power some lights? It will be a fun project and a great conversation topic. How many 60 watt light bulbs could I power with this small unit? Does anyone have a generator with a blown motor to sell cheap? Does anyone have an old gearbox laying around that may help? I am willing to build the prototype around old parts that I can aquire as cheap as possible. I have access to any type of angle iron and welders and such that I may need. Hardware odds and ends are not hard for me to come by. Let me know if anyone can help with parts.

For an home-built lashup, you are probably best off with off the shelf
proven components.
* A belt driven automotive alternator, (with regulator),
* A couple of automotive batteries in parallel,
* A comercially available inverter power unit, (available up to 3 KW. rating).
These units will automatically work together to generate, store, and deliver
power on demand. The difficult engineering is already done for you.
Just plug in and Bobs your uncle.
I would suggest a larger prototype wheel though.
A light frame 6 Ft. or so in dia., should be easy enough to handle, and give
a more useable torque.
You might even let the shaft run in vertical slots instead of fixed bearings,
allowing the wheel to ride up over any floating ice in winter.
Best of luck. I would be interested to hear how you make out.

Yeah, well, I am not sure how pragmatic you are Pragmatist! And what does my Uncle Bobby have to do with anything?

You did not say what type of wheel to use, but let us assume that either an undershot wheel is used, as Bill proposed, or a vertical shaft "scoop" design is used, as proposed by "Guest". Assuming 100% efficiency, with the wheel not able to turn any faster at its circumference than the current is pushing it there, 5 MPH current becomes 23.34 RPM with a 6 ft. wheel.

Here is the math: 5 miles/hour x 5,280 ft. / mile = 26,400 ft. /hr. = 440 ft./min , then

Circumference = Pi x Diameter = 3.14159 x 6 ft. = 18.85 ft. , so

Angular velocity = Circumferential speed / Circumference = 440 fpm / 18.85 fpr = 23.34 rpm

How many amps can you get out of an automotive alternator at only 23 RPM? OK, let's assume your belt-driven alternator uses a pulley with a 5X ratio and still has enough torque to drive the alternator under full load @117 RPM. Ok, make it a 10 ratio and 234 RPM. Do you want a 15X pulley system? Well, with a 4 inch shaft, you would need a pulley wheel almost as big as your water wheel! OK, so you built your huge pulley and now have 350 RPM. When my car engine idles (300-400 RPM), with plenty of torque, the 13.4V alternator still pulls down to just over 11 volts (with a fully charged battery in the system) when I transmit with my ham radio set at 20 watts output (about 3-4 amp current drain @ 12 VDC = 36-48 watts load). And I do not transmit nearly 100% of the time. I get to talk maybe 20-50% when talking with others, my receiver only draws about 1 amp. How many 60 watt light bulbs are you going to light with your set-up 100% of the time? One, if you are lucky.

Might be fun to light up the dock that way at night, but hardly enough juice to keep the old cabin warm at night during a cold Michigan winter!

How about this: Suppose the wheel is overshot instead of undershot. The torque could come from 300 pounds of H2O on a 3' arm: lets say 900 lb ft. That would enable you to get a generator turning pretty fast through a double or triple reduction.

Or... Something on the order of a ship's propeller, (but lighter gauge for the lower horsepower required) could also provide a lot of torque at low speed.

As someone mentioned above, tow-behind alternators work quite well and are tiny. The crudest of these produce about one amp (at 14 volts) per knot. So in your case, lets say 4 amps at 14 volts = 56 watts. Put ten of those in the water and you'd be generating meaningful amounts of electricity. You might want to make your own from used car alternators. Prop and shaft underwater, rope to alternators on dock.

I wonder if you could get a really large used prop from Michigan Wheel (that maybe couldn't be balanced, or which was cosmetically too far gone, etc) Something from a 400 hp inboard, for instance. (At the slow speeds and low hp you'd be using, problems that would make it unusable on a boat would be of little concern.) In four knots of flow, that might give you about ten shaft horsepower, or about 7.5 kilowatts. (I'm working backwards from an estimate of the hp required to turn it for that boat speed, so it's rough, but in the ballpark.) (You'd need gearing, and probably a rewound alternator)

A river that deep flowing at 5 mph represents a tremendous amount of horsepower. All you need to do is extract a little. Think of Henry Ford and his river.

Wind turbines blades move slow but that is done away using gear arrangement when it reaches the generator. 440 RPM or other similar generators may be just fine. If exact 5-/60Hz power is required then one need to convert this to DC and back again to desired frequency AC using inverters. DC will also allow storing power on batteries such that Generator can be easily services for few hours without causing power failure. I get 4-hours 1kW rate or total 4kW power from two truck lead acid batteries. This back up is working for me for the last 5 years.

Ken,

I think your used propeller idea has the most merit, since the original poster was looking for a low cost system, however it would probably need something much larger than an automotive alternator for any significant amount of power. See my comparative RPM scenario. Do Semi-tractor engines have higher output alternators than standard automotive?

For casual emergency power (limited lighting and to keep a furnace electronics and fan going during a blackout), the tow-behind generator might be adequate, but buying ten of them could be very expensive, and you would still have only about 1/2 kilowatt. Electric heating, especially if it was resistive, would take a lot more than that!

Also, the overshot water wheel is a great idea if you have water flowing down a hillside, say from a mountain brook, artesian well, or spring creek, however near a larger river you don't have much drop, the valley area being mostly level. With a 3 ft. arm, the wheel diameter would be 6 ft, which would be the amount of drop you would need to get the most power out of the water weight. Where is all that water going to go, unless you have a storm sewer at or below that depth nearby that can handle that continuously? Plus, you are going to have to dig a trough deep enough and wide enough to handle your wheel, and hope that pressure from ground water so close to a river does not flood your works continuously!

Hopefully, their dock can handle the extra strain of your propeller along with the normal current pushing against it. If so, you may just have a winner of an idea there! Put the mechanical apparatus on a hoist on a swing-arm and set it on the bank during the ice flows, unless it is so cheap it could be easily replaced if the dock was lost due to "icebergs". Have to do a cost/benefit analysis on replacement cost versus down-time (value of the lost power).

I am wondering what kind of docks are used in this river. Are they mounted on piers sunk into the riverbed or are they floating docks, secured by shore-anchored cables up-river?

The docks are very solid, 8" diameter steel pilings sunk 15' in to the mud. At this point I think the water wheel is the easiest way but I don't know if I can get away with making a wheel for every boat and neighbor going by to see. Since I have access to all the sheet metal and structural iron that I could aver need, if I made a steel box 4' x 4' x 8' long and mounted a turbine in it, maybe I could seal the gear box and the alternator inside and have the whole unit sit on the bottom, the current is also much stronger there. Then I could have the cables come and connect to a battery and inverter storage box under the dock. How big of a turbine would I need to turn a semi tractor alternator, with the correct gearbox, assuming we have a 7 m.p.h.+ current? I could also set up fins to catch more water than the 4' x 4' opening. How feasible would this be?

One problem I see is the idea of putting the electrical equipment at the bottom of the river. Sealing electrical equipment under pressure from water is difficult enough if you have to run a cable outside the box (to transmit the electrical power), but to also have a dynamic seal, which would be necessary for the propeller shaft or gearbox (if it could be sealed independently) output to be run in through the wall of your enclosure and coupled to the alternator input shaft, would be extremely problematic and fairly costly. Maintenance would be a problem also. How would you ever know if the seal developed a leak?

More likely, you could keep all your mechanical components underwater (perhaps even the gear box if it is sealed well enough) and bring the output up as a rotating shaft. Once outside the water, the shaft could be coupled to a weather resistant enclosure housing the alternator, preferably on or under your dock if there is room. I would suggest bringing the current to shore as DC if it is a short run. Use as much of your power as DC if possible, because the conversion to AC through inverters is fairly inefficient, especially for high power applications.

Conversely, if you can find a used AC generator, perhaps one which has a blown engine but is otherwise in good condition, you could have a good source of AC current and would not need any inverters.

STL:

Yeah, the overshot wheel is wishful thinking. He didn't, after all, mention and old dam any where near.

And yes, electric heat would be pretty well out of the question with an array of tow behind generators. For them to be even remotely economical for powering the other things, they'd have to be home made, with used alternators, scrounged props, etc. Some of this description are found on sailboats. The type that are actually manufactured for sailboats appear to be made from gold, judging by price.

With a big enough prop and the right gearing, it might be possible to generate enough to run all the usual stuff (through inverters) and maybe even run a small water source heat pump. The water for which might better come from a deep well, at 50 degrees f, rather than from the river.

Wouldn't it be great to be energy independent? While looking for other stuff, I've stumbled across a couple of sites where they discuss this kind of thing all the time. Can't think of any names, but googling water generator etc. would probably turn up something.

While I am impressed with the amount of feedback this discussion has received by now, I must say that it is risky to use river shore water power. You need to have very stable platform that will hang on for the entire water flow period of one year. All those equipments used in fast boats will not work as river flow rate must be very slow. You need large blades in the wheel to get some force generated and then translate this into high speed motion of about 3600 RPM to get 60 Hz AC through generator. Wooden rafts and wodden wheel may be fun and if made from wood of trees that can take on water for many years, then it will do job much better. Some wood actually work better under water and was used to make small water crossing bridges. Use the same wood.

You have to go some 10m in side the river to get into flow. This will need some structure. Make something that is used for watching tiger in the river using poles, firmly attached to each other and create minimum friction with water. When you place a wheel, it will extert huge force on the fixture as it is not a true torque and only one side applied force. It will try to make the platform move.

If you had scientific knowledge in ancient time them this is the way you may be planning aand only thing missing at that time may be the generator which wasn't discovered by then. Have fun. I like this idea as you can make an automatic river flow and river water level warning system using river power. This is something mat help those living near river. Have a small wireless system that tell you of danger and do some data logging also. You can sell the data to EPA and perhaps get some good fund from them. Don't call it ower generator, call it river ecology research station and ask for some funds from national Research Council www.epa.gov and I am sure they will funds 100,000 US$ for exchange of data and also you can run an expedition program for others for US$2000 per week for your project. It can be more than fun. You can make me a joint project research scientist if you like. My life is mostly in the environmental research projects. I feel you have great potential to experiment and learn from real life experiment. Collect all data - success and failures and publish a book.

Here is a decent site for checking out small stream hydro generator systems.

http://www.green-trust.org/hydro.htm

Hello JRAEF,

Excellent link, good picture and clear idea.

I think this can also be used on an anchored boat in the mid of the river to generate power while you are fishing out there. If you can firmly hold the boat on water then this small thing can be pushed into water to get some force to rotate the water wheel. Putting on the river bank, with stable platform is an excellent idea. I think who so ever can have fun with such power is just great thing to do.

I highly appreciate this idea.

Guys,

I stumbled upon this website on a Google search asking about how to convert an old water mill to generating electricity. Just a bit of background. I live in Lancashire, England, not unfamiliar with water power for cotton mills. However, my background is in the telecommunications industry with BT as a maintenance / planning engineer for large PABX phone systems. I hope you will therefore forgive my ignorance on the nuances of mechanical and electrical power generation. I was fascinated to read the exchange of "e" mails and all the participants have good knowledge and their own take on how things may be achieved (like all engineers should!).

How I got interested in this, is that I may have an opportunity to purchase an old water mill in France and therefore the chance to generate my own electricity.

My question to you boffins is this. I would have thought that the power needed to turn a millstone( sufficient to make all the village flour ) would be sufficient to generate enough electricity for a domestic house i.e. a converted Mill.

I appreciate that the question is a lot simpler than the answer, but have any of you got any practical experience of the logistics involved for the equipment needed and the expected power generated.

Sorry chaps, but this is better than watching television !!

Regards, Gerard.

Gerard,

There are a lot of knowledgable people here who might be able to help you, but first you need to provide more information.

First of all, your question is just too nebulous, is the power needed to turn a millstone ( sufficient to make all the village flour ) sufficient to generate enough electricity for a domestic house i.e. a converted Mill.? Your answer would be just as nebulous: Maybe. The unknowns are way to many.

How many people in the village when it depended on the mill? How much bread did they eat daily (flour usage). Did it provide all their needs, or was some flour imported, or even exported? How efficiently did the mill crush the wheat? How big was the wheel? How fast did it turn. How long did the mill stand idle each day? Even if you knew all these, there are probably no known equations or relationships between some of the unknowns to calculate available river power.

A better way to go about this is to gather more scientific data about the power source. How fast is the river at the mill site (current speed)? How wide and how deep (cross-section)? Is there currently any improvements, i.e. mill pond dam, mill race, etc. and what are the parameters, e.g. height water behind the dam to river below the dam, area and length of mill race. etc., speed of water in the race. Also, what are yearly average, high, and low figures for all of the above? Is there navigation (boats, barges, etc.) on the river and must the mill site accomodate such river traffic? Does the mill site have clear title to the whole river (both banks), and just what water rights come with the property? You might find you are legally constrained from doing ANYTHING in the river! Now, with those questions answered, we might have some handle on the potential power.

Next, let's look at consumption. What are your energy needs? Is the electricity just for lighting at night, or do you need it for hot water heating? For winter heating and/or summer air conditioning? How many BTU's will be required for heating/cooling (average and maximum daily)? How much money do you have available to purchase generating equipment? Will you have electrical storage capability (batteries and inverters), Will grid power (public utility) be available for peak demand or not? What other special power requirements will you have (charge batteries on electric vehicle daily, for example)?

If you can answer some of these, or get answers to them you can create an energy budget, and then.... you may have a fighting chance of getting a rough answer to your question!

You may then want to start your own thread, just as the fellow did who started this one!

STL,

I do appreciate that I will need to gather all the technical information I can in order to arrive at something technically achievable. This knowledge is not available to me at the moment. However, I will be visiting the site next week and be able to get much better feel for the potential.

I must admit that having researched the way old water mills work, I am revising my opinion on what I thought were high friction, high energy machines. Naively (possibly?), I thought that modern, small scale turbines / generators / alternators would be lower frictional devices and therefore input power would be less of an issue than I imagined.

As regards system design, my first thoughts would be a trickle charged UPS / Invertor system.

I would be looking to power lighting, fridge / freezer, TV & PC equipment. I guess the fridge / freezer would consume the most power, as the others are ad hoc. No cooking or heating.

The Law question has not escaped my notice either. I suspect that solving the mechanical / power problems will be simpler than satisfying French Law!

As I asked originally, it would be nice to talk to someone who has actually done this manoeuvre. Any advice would be gratefully received, even if it was don't bother!

If I do purchase this property and make some headway into producing my own electricity. I will be more than willing to share my experience with you.

Thanks STL for your feedback.

To be continued.....................

Regards, Gerard.

Forget power generation for what you are suggesting. All those heating and cooling demands are power hungry. I would wager you'll never be able to generate more than enough to power a few light bulbs during periods of power outages. As you even mentioned a trickle charge or a little better to power an inverter. If you rip out the whole thing and put in a hydroelectric generator maybe something worthwhile but probably not at all worth the investment unless you are a survivalist and willing to pay extra for power. It's a nice dream but hardly practical.

I suggest restore the mill, make your own flour and open a bakery for the fun of it. Charge admission to tourists to see a restored flour mill and buy your home made bread on a hopefully scenic French stream and use the money to buy electricity.

You have grossly underestimated the power of water. Depth of few meters of river even with small flow has very high power. You forgot that Tsunami wave. It is hardly more than that high. It can through a loaded truck 10km inside the land.

People in India tap only small water flow and drive grind wheet in water powered drinders, which is a heavy grinding mill of capacity running to tons of processed wheet per day. River can cut earth and make its path up to sea is full of power all the way. If you use too much power then the entire platform will be pushed by water into the river.

As you say yourself,

"People in India tap only small water flow and drive grind wheet in water powered drinders, which is a heavy grinding mill of capacity running to tons of processed wheet per day."

Isn't that what I suggested the gentleman do with his French mill?

Isn't it obvious that if a stream of water was so accomplished an electricity generator everyone would have a power generator in their stream.

Tsunamis travel at 20-100 knots. Of course they have imense power for, Oh My God, 5 minutes. Then what?

Sail4evr,

Yes, tsunami is a bad example. And you have a good point about restoring the mill as a tourist attraction. But if Gerard has no interest in such a venture, the suggestion is pointless. And after hearing a little of what his energy needs would be, it does not seem so outrageous, since the biggest demand would come primarily from his refrigerator and freezer which should be fairly constant. No cooking, no heating, so most peak demands would be small. I will assume that Air conditioning is not necessary in that part of France, although some fans might be used on the warmest summer days.

Really, all Gerard needs to do is review all the suggestions previously given in this thread and see how they might fit his situation. The biggest hurdle, as you touched on, is the acquisition costs versus the annual net benefit in terms of reduced energy bill. Obviously, Gerard is thinking in terms of reducing his reliance on commercial energy resources, and saving money in the long term. Many energy savings projects become "do-able" if you look at it as a long-term investment and compare the rate of return to what you would be able to make with other low-risk investments. Then there is the intangible benefit of having emergency power available.

Even if you are not a die-hard "Survivalist", the thought of remaining comfortable in your own home during an emergency, when others are seeking escape or shelter elsewhere, is very tempting. However, not knowing much about the location, I wonder what emergencies could cause power outages? Surely, there are no dangers from hurricanes, typhoons, mudslides, earthquakes, volcanos, tsunamis, etc. Is there even any danger from tornados/cyclones in that area? Unless he is worried about a terrorist strike on the local power plant or power grid, disease epidemics, or civil unrest leading to violence and anarchy, it would be hard to see what "emergency" he might be preparing for.

STL,

What you may not realise is that their are still some remote locations in France that do not have public utilities to them. This can be expensive to get installed. I will know next week whether this is one of them ( I hope not ! ). Even if there was Mains electricity, I would still look at the economics of supply from the river.

Sail4evr's idea of restoring the Mill is novel, although I can't see my wife getting up at 4 '0' clock in the morning.

Don't worry, I am not a survivalist. The thought of living in a world of Cival servants does not appeal. Give me a quick death. not one slow lingering death by taxation.

Au revoir.

Gerard.

Gerard,

I guess what you meant was that your wife couldn't see you getting up at 4 am

sail4evr,

She certainly wouldn't.

Gerard.

Forget the economics, if you want to produce electricity from your stream, then do it! You can slowly evolve your system and learn along the way as you feel like investing more into it. Do it for the fun of it!!!!!!

Of course if money is no object...restore the mill, downstream build another dam and install a hydroelectric generator built from scratch, engineered to take full advantage of the resource.

I'll second that! There are all sorts of possibilities, and as the system is developed, a backup generator could keep a bank of batteries charged if other things failed. Solar panels, wind generators, passive or active solar heat could all help with energy needs. There are many houses in the US and elsewhere that are entirely free of outside energy sources. If you have the time to experiment, and if you put a backup in place early on, then even if don't achieve total independence, the process alone (the learning and doing) makes the effort worthwhile.

As I've told many people when encouraging them to learn to fly: even if I never made any use of my pilot's license after obtaining it, the process of learning to fly would be reward in itself.

Amazing what can be done when money is no object

If money is no object.....Forget France! Move to, or buy, a tropical island with no volcanic activity, little population, friendly natives, no traffic, no air pollution, fresh water streams, lots of wild game and fish, fair breezes (for cooling and for power generation). Build a magnificent villa, get a Ham Radio license (for fun and emergencies), and install a satellite Earth Station, for TV and Internet. If you must have company, and family is not enough, build a guest house and invite select friends to vacation with you. I guarantee no one would turn down such an offer!

This has gone a bit off track, but Gerard, it really still comes back to the details. A grinding mill using a water wheel could have originally been put in place to aleiviate the work burden (and feed cost) of a single horse or donkey! Think about that in terms of power, that is essentially 1 horsepower, which in theory, relates to be 746 watts. So if that was the original design of your particular mill, you will not be able to extract much more power than that without major modifications, in which case the cost may very well outweigh the benefits.

In spite of that, a water mill ALWAYS represents a water drop, which is refered to as "head". Head of water can always be exploited to produce electricity, but the amount it can produce is also directly tied to "flow", the volume of water moving through the head, and "continuity", the amount of consistant reliable flow over time. So you could have lots and lots of head (think Angel falls), but very little flow (think garden hose) and you would not be able to generate much power. On the other hand, if you have lots of flow at very little head (think Mississippi River) and you could generate lots of power IF you can find a way to harness it. But the third component, consistancy, is equally important. Think of the tsunami example from above; lots of flow, very little head, but only for a breif moment. In your case, if you measured flow in April it may look great, but in December when the stream is partially frozen, or in September before the rains resume, you may not have enough flow to make anything consistant.

So in order for you to assess the viability of your project, you must measure the head by looking at the drop distance, the flow, using a flume measurement device, and also the consistancy over time. If this information doesn't already exist, it would be at least a year before you could accurately begin to determine the power capabilities of your mill.

what a great discussion! I looked in after googling "river generation" cos I live on a houseboat on the Seine in the middle of Paris and thought I could save some money by "harnessing" the current. I'm none the wiser, but perhaps less naive, if that's not too contradictory. Thanks

Hi Gerards!

I think You are right. If there was a water mill, Your needs will be fullfilled also.

Economisc: depends mostly on Head = difference in water level before dam and after.

Proportions of cost: from scratch 70% of costs is what is to be build below water level = dam, channel,... But if this is ready and in good conditions (check in summer time when water has low level! before buying!), and head is more than 2m, than probably You will get what You need. But, what to take into considuration: The smaller river, the bigger variations in water flow. In mountains high water to low water can be as 1000:1. Measure Q= volume of water flow per second. 1m^3/sec with head = 3m will give about 15kW of electrical power, enough for needs You listed, and to have heating of home for free. Or to cover usual needs of five neighbours.

If You would install heat pump,(see my comment to Stackpole77) 2.5m head and Q = 0.5m^3 will give You 3kW of electrical power and 15kW of heating power, enough for 150m^2 floor house.

Amount of water flowing is usually accessible at local water authorities. Can be also calculated from the area from which rain water goes to this river, above Your mill.

But .. moving to France, may be You will loose more in earnings, than gaining from water! But may be You will live longer then , drinking French wine!

Good luck!

czgut

I understand Your data as follows:(correct me if I am wrong):
River/channel depth = 8 feet = 2.4m, channel width = 10feet = 3.05m, water speed = 4...5mph = 2m/s.
This makes water flow volume Q = 2.4m * 3.05m * 2m/s = 14.64m^3/s.
This amount of water, with speed 2m/s has kinetic energy/sec = mass * speed^2/2/sec = equiwalent to 29kW.
So if You could use 50% of this energy, by wheel , or water turbine, You would get 10kW, at the expense of water speed.
But this would require a wheel slowering all water (as wide as channel, and as deep as water, and axis above water level) Means very big.
If there is a difference of water levels, or is possible to make a dam, making for example head h (difference of water level before and after a dam) equal to 1m, You would get water power = Q * h = 145kW.
Assuming horizontal water turbine efficiency * generator efficiency = 50%, would give roughly 70kW of electrical power.
But probably You cannot make dam, or at least not so high as 1m, because difference between two lakes is only about 2m.
May be You could make 20cm dam, which would allow You to have some 10kW of electrical energy. But so small head makes installation of turbine not efficient economically.
Putting a wheel smaller than from bank to bank of river and from surface to the bottom is playing, because water will omit wheel.
Summary: probably possible head is too small to make installation of water turbine reasonable (from economic point of view).

But what can You do: You can have house heated by heat carried in water.
To heat 150m^2 floor house You need about 10kW of heat energy in winter time (in average).
If You will install 80m 1" pipe at the bottom of the river (below ice in winter), and install heat pump, You can have this 10kW of heat energy from about 3kW of electrical power needed by heat pump.
If You will install heat pump at home, or use heat from pump engine, You will have together about 13kW for heating house.
Now You can calculate if it is reasonable. (I do not know the price of electrical energy, and heat energy now used by You).
I think You can buy easily almost ready heating system based on heat pump.
The only difference is , that pipe is not in ground, but in river.
Putting pipe in river; the higher flow, higher efficiency of heat absorption from water.
And Your heating system would lower temperature in river only about 0.00016deg, so fish will not get cold because of You.

But you should use clean water in Your system so that when in case of damage, You will not pollute water in river.
May be this would require adaptation of heat pump system - may be they add alcohol to prevent from frosing.
And You should check if this (installing pipe in river) is allowed by American law.

This are rough calculations. More data would be needed to calculate more exactly.
Summary: excluding initial cost, You can have 13kW heating at a price of 3kW of electrical energy.

Good luck Mr Stackpole77!

czgut

Addition to my answer. I do not know exactly what dock means. And what has 35feet. Is it a depth of water after waterfall or it is a difference in water levels before and after waterwall? Most important: if as it is now there is a waterfall and difference in water levels is more than 1m. You can install power plant. From each meter of head (difference in water levels before and after waterfall) You can have about 50kW. There are power plants in pipes. Pipe is like big U upside down. One end is in water before waterfall, another in water after waterfall. Turbine is inside pipe. If You will pump off air, then water begans to flow from upper level to lower level, like through ordinary pipe. Flowing water rotates turbine, turbine rotates generator and You can have power. This pipe can be on the bank of channel - easier to install, check, maintain... . Only ends of pipe must be in water. And You must make some kind of rack to prevent floating debris to get into pipe.

If You want to stop - just open air vessel at the top of pipe and allow for air to get in. Water will stop to flow.

If You want more details, write to me.

czgut czgut@vp.pl

Check this company. They manufacture exactly what you want. I read the other replies and found them mostly incorrect. http://www.althydrosolutions.com/

My children and I are putting together an underwater generater for their science class. Our approach is to submerge a container to create an air pocket under water. Inside the air pocket are rods with blades that spin with the current. Each rod is connected to a small homemade generator (science kit type). In our case, the three small science kit generators light up simple light bulbs just fine but, I would think, this should be able to scale. I suppose this would remove the need to a large 30" wheel and it could be placed under the freeze line.

Oh well, I am soooo not an engineer. But I think this is kind of stuff is fun.

- Beach

Then use one of Your units to pump air to this container. Otherwise, after some time all the air will be soluted in water and there will be no air. And may be Your gererators are not water resistant. Moreover, extra air will make water more rich in oxygen - good for fish. But may be better idea is to make all electricity above water level -on some swimming piece of styropore, attached to river bank. Children can see how their machines will be working. And remove all stuff for winter time.

For fun all You said is true. But with bigger money better efficiency is better- and bigger water wheel or more efficient turbine gives more money back.

Have a nice time!

Thanks for the tip. We, heh heh, found out the hard way, that the generators don't work well when they are wet. So we have the container split into three sections. The middle section has the blades with two 'generators' in compartments on each side. A small bulb (from a flashlight) is connect to each generator. There is a plexiglass (actually, the container is all plexiglass) barrier with rubber washers to help keep water from coming in via the rods. This was tricky at first because the rubber was too tight and was keeping the rods from spinning. There is still a little leak but for a science experiment its ok.

By the way, the container is in a larger plexiglass tube. I have a small water pump attached to it to simulate water flow (intake on one end - outtake on the other). I need to add a drain.

Interesting point about the air. We haven't observed something like that yet because we only run it for an hour at a time. The plexiglass does get a little foggy tho.

My thoughts about about using smaller units instead of a big one. As an IT professional by trade, there has been a big push (and acceptance of) using a bunch of smaller servers instead of a big one. I wonder if the same would be true here. If there were a bunch of smaller generators lined up to equal the distance of a circumference a 30" wheel then could enough electricity be generated to power something meaningful? I expect that the smaller generators would not be as efficient so another x number of feet of smaller generators may need to be added to make up the difference. Hmmm, how many generators that are used for wind would be needed to get meaningful electricity from water? I wonder if you could use something like this in the Detroit River. I remember watching a news report about sunken ships at the bottem of the river. The report noted that he had to anchor himself because the current was so strong. What is strong though? 1 mile per hour? 5 miles per hour? 10? 15?

Heh heh, I'll have to play with this even after the science fare.

- Beach

I thought that Your air pocket was like open box upside down, put in real river,(english is not my native) with half of the wheel in water, and upper half in Your pocket air. And turns , because of water flow pushing lower part of the wheel, upper half being in this air pocket. If it is hermetically closed from all sides, than no problem (if no leakage).

In general about power from river: Difference in water level is like voltage at electricity side. Flow of water resembles flow of current. Bigger difference in water level (bigger slope: difference in height/100m of distance) quicker water flow - more powerful river.

Main idea: If You will put obstacle (dam) , the difference between uppper and lower (after dam) water level will grow up until water will flow above dam. If You allow this water to go through Your turbine, or water wheel, You can use its energy. One cubic meter of water at the height difference 3m has 30kW of energy. Water wheel has efficiency of about 40% ... 60%, (the bigger diameter, the bigger efficiency). Turbine effficiency is about 40%...80%. Gear + generator efficiency is about 80%..95%. So finally You can have some 30%..70% of this 30kW, which makes 12..21kW.

But if the water will have possibility to omit Your wheel, it will do it. So it is not enough just to put wheel to the river. Water will omit Your wheel and may be You will get 500W instead of 15kW.

In general: all home made wheels and turbines have low efficiency. So for fun every wheel is OK. But if You would like to have real energy from river then:

Most expensive is building of a dam , some 70% of alll cost. If You have natural waterfall bigger then 3m and amount of water is more then 1m^3 - You are lucky and You can save much from this 70% and have profitable power plant. Otherwise investment probably will not pay for it. Key parameters: amount of water/second, and possible difference in water levels befiore dum and after. You will need also to build stairs for fish, to climb and jump above dam. And You will need permition to build dam. And You cannot stop all the water. Minimum amount have to flow all the time (to conserve biological life in river).... Long story...

Coming back to generators. Usually one bigger 3kW can have higher efficiency then three smaller 1kW. But quite often in water power stations there are more generators. The reason is this, that amount of water flowing in spring time can be 10 times more then in summer time. So summer water having 5kW, turning 25kW turbine and generator would give may be 0.5kW, while 5kW turbine and generator would give 3kW. And another 20kW turbine and generator set, working when more water flows.

With water and generators is not like with servers. Water just want to go down by easiest way, omitting any obstacles (work). Server cannot omit work -is preprogrammed. Water is preprogrammed to go from higher level to lover. If You will stop all other ways and leave the only way through tyrbine - then it will work.

But I think Your idea is very nice - this plexiglas, so everything can be visible for children. May be another idea would be to put different wheels - with water flowing above wheel, with water flowing below wheel, flowing through turbine, ...each having generator, with power indicator, so efficiencies coud be compared..

Nice fun..

"But I think Your idea is very nice - this plexiglas, so everything can be visible for children. May be another idea would be to put different wheels - with water flowing above wheel, with water flowing below wheel, flowing through turbine, ...each having generator, with power indicator, so efficiencies coud be compared.."

Ooooo, I like that idea. I'll have to get some more materials but it would be worth it. I still have to carry this into the science fair so I will have to limit this to 3 wheels. Maybe 18', 12', and 6' wheels. Instead of attaching a lightbulb to the generator, can I use (again, I am so not an engineer) a voltmeter? I would mount the voltmeters on the side so the kids can compare the power output of all three wheels. If not a voltmeter then do you think I can pick up something inexpensive from maybe Radio Shack?

Thanks for your input.

- Beach

I think it is more didactical to compare two wheels:wheel with water going above with wheel with water going below, and using the same head (difference of water levels). And using the same diameter, and using the same generators - so efficiency could be clearly seen and comparable - that everything is the same, only output power differs.

1. you can leave bulbs You have already, if their light is OK.

Measure the voltages generated now with voltmeter. Then for this range of voltage I would buy in ebay.com simple analog voltmeters - they are very cheap. May be rectifiers would be needed if voltmeters are for direct current. If your generators give DC current, then not needed. And connect each voltmeter in parallel with each bulb.

If we have much time I can send drawings to You by letter.

czgut czgut@vp.pl

May be most teaching would be to make regulated head (mechanically) , to add voltmeter to this what You allready have, and demonstrate dependence of Power as a function of head (difference in water levels before and after wheel/turbine)

Havew a nice time

czgut

Thank you so much for your feedback.

:( The teacher wants us to simplify the science experiment. Something about the science fair being for kindergarteners and not for dads - lol. Ok ok - maybe I was having a little too much fun with this. We are now doing some sort of rotting banana in a glove thingy instead. I have to read the directions for it.

Still we will keep doing the project. My son and I went to home depot this weekend to pick up a few parts for the under water wheel. Now that the weather is nicer we are moving this to outside to the garage and we are turning this into something interesting to do with the neighborhood kids.

I was wondering also if we are not going too deep.. ==> my last simplifications.

..yes, We should start from the age of viewers, choose what we want to show, and then design the project...

Anyway, I think, small model of water wheel, made to the scale, resembling real wheel would be good. After seeing this children could easily recognise real water wheels (if they still exist in USA). And they would know what for they are (they were).

But Your son for sure will benefit from this project. And also his neighborhoods.

check out classichydropower.com should work well for you as the weight can be added to the counterbalance and the whole unit slides in out of the river on the mounting pole.