Noob to micro-hydro

Hi All,

 First post in the forum.  Can any one direct me to some good resources on micro-hydro generation?  I've found that solar info and design is pretty well covered, but, hydro on a small scale seems to be all over the place and I'm just not familiar enough to figure out how to approach my own system.  It seems all over the place because everyone's setup and needs are a bit different!
 

  In our case we've got a pond with an overflow which goes underground via a large pipe (~2' diameter) and then into a secondary area.  The previous owners (who I would have liked to meet!) had put in a 4" pipe higher up to what appears to be a homebrew waterwheel.  The son said his dad tried and tried to get the WW to work, but never got it going like he wanted.  I'm thinking maybe with the newer stuff, I may have another options!

Thanks!

J

Maybe there is not enough water flow to the waterwheel or not enough speed.

The problem might also be the size of the waterwheel, maybe too small or too big?

I feel you are right that everyone's situation is different.

Maybe some help:

https://permies.com/t/151598/Waterwheel-Power-expectations

https://permies.com/t/151776/Water-wheel-Lots-questions

Joe Hetrick wrote:Hi All,

 First post in the forum.

J

Welcome to the forum! So glad you are here and hope you find lots of great answers to your questions!

Hi Joe;  Big Welcome to Permies!
I have lived with Micro Hydro since 1996 and low voltage solar since 1983. We are 100% off the power grid.
You are correct that every system has different needs.
My system is high head and low flow (300' vertical drop in 2200' of 1.5" line using only 3-5 GPM) I make 80-130 watts @12vt 24 -7.
I use a permanent magnet Pelton wheel with a single nozzle, I have 125 psi water pressure at the house/ hydro.
Your system would be high flow with a low head if your intent is making power.
You would use the same Pelton wheel with four nozzles.
Some folks would want the water wheel simply for aesthetic looks rather than power generation.


My first question is, are you hoping to make usable power from this water?
Do you have grid power at the site now?
Are you off the grid already? (Solar)?
What and where is the "secondary" area that your 2' pipe goes to?
If you know, how much water flows through the 4" pipe and or the 2' pipe?

I have to tell you that unless you can make bunches of power, hydro is expensive to set up and noisy while running (you do get very used to the noise).
If you need or just want to be off-grid, then in my opinion high voltage solar is by far the easiest and lowest cost (also silent) way to create your own power.

Thanks folks; I guess I should have stated what my goals were .  i didn't go into too many details about the current situation because I didn't want things to get overly long!

- The current waterwheel is probably 6' in diameter and probably 18" wide.  I didn't count the number of paddles on it.  The entire situation looks like it was intended to be fully homebrewed, with probably some sort of salvaged motor being driven by a pulley.  It seems to me like it's probably not worth pursuing  that path.  The water flow was intended to go via a 4" pipe buried under the spillway, but, which sits at what I would think is a relatively high point with little drop.

- i don't know what you actually call it; there isn't an open spillway/water tumbling over a dam, there is basically an 18" or larger drain that goes down some number of feet (Lets say..5), exits out a similarly sized pipe and goes into a lower swamp area that eventually drains off the property into a nearby stream.  We had a drought last year and the level of the pond/lake dropped below the drain for about 6 weeks.  I missed a good opportunity to do some measuring and planning, but, I expect there will be another opportunity.

Goals:
- The location does not have grid power.  It's basically a cottage in the middle of our farm.  I have a small solar setup there now with enough capacity to do reasonable things: Lights, in the hot summer when lots of light I can run a small fridge to keep items cool.  Can run modest appliances when needed.
- I'd like to supplement this with something that may be more "always on".  The winters can be pretty dim here, so my battery + solar installation can't currently keep up with even modest use.  The spill doesn't seem to freeze until the coldest parts of winter, but that's not a huge deal, we're not back there.
- I have a 25ac pasture behind this with no access to power or water.  I'd like to be able to run a pump from the pond to provide livestock water w/o having to haul it.  Pond is at nearly the lowest point in the property, so, I can't use gravity to move water!
- I would like to learn a bit more about microhydro, and, it appears I have a pretty good opportunity to do that.

So, at the moment, this isn't trying to create a fully off-grid permanent living space, more of a seasonal one; using what resources I think I have.  Depending on what I learn and what the future brings, that may change.

Thanks folks; I'll finish reading up responses and ping back with questions!

Joe

Thank you so much; this is really helpful perspective.  I had been wondering if the..easier route may be to invest more in solar.  Your experience is really helpful.  I've just not been around hydro power at all to even have a feeling for the shortcomings/benefits over other.  Solar may be the win, unless I want to just play with very small scale microhydro for fun/limited use.

thomas rubino wrote:Hi Joe;  Big Welcome to Permies!
I have lived with Micro Hydro since 1996 and low voltage solar since 1983. We are 100% off the power grid.
You are correct that every system has different needs.
My system is high head and low flow (300' vertical drop in 2200' of 1.5" line using only 3-5 GPM) I make 80-130 watts @12vt 24 -7.
I use a permanent magnet Pelton wheel with a single nozzle, I have 125 psi water pressure at the house/ hydro.
Your system would be high flow with a low head if your intent is making power.
You would use the same Pelton wheel with four nozzles.
Some folks would want the water wheel simply for aesthetic looks rather than power generation.


My first question is, are you hoping to make usable power from this water?
Do you have grid power at the site now?
Are you off the grid already? (Solar)?
What and where is the "secondary" area that your 2' pipe goes to?
If you know, how much water flows through the 4" pipe and or the 2' pipe?

I have to tell you that unless you can make bunches of power, hydro is expensive to set up and noisy while running (you do get very used to the noise).
If you need or just want to be off-grid, then in my opinion high voltage solar is by far the easiest and lowest cost (also silent) way to create your own power.

Basically power is vertical drop times mass flow rate.

Using the system above for an example calculation:

300 ft head * 4 GPM / (60 s/minute) * 8.3 lbs/gal = 166 ft-lb/s


166 ft-lb/s / (550 ft-lb/s /hp )
= 0.3 hp

0.3 hp * 746 W/hp = 225 W.

Assuming 50% overall system efficiency (as a product of small losses in multiple stages)

112 W output.

Hydro Power follows the follows a formula so if you can give us your flow rate and the elevation drop we can see if there is enough power to extra from the system.

Net Power =  50% effficency *1/5 * Head * Flow
Net Power = 1/10 * Head * Flow
Net Power = 1/10  * 25ft * 4gpm
Net Power = 10W
(barely enough to keep a LED light bulb going, and the home-made waterwheel will most likely not give you those effiecency values)

Solar is mostly your best solution, hey could just be some panels on some lumber that you roll out when your are onsite and stow away when you leave. You can also install some panels by the well and use them to irrigate the land, when possible. It's possible that you could build a pond at the top of the land, and pump water up to it from the bottom swale and then use gracity to irrigate the property.

Maybe installing some earthworks will mean that your plans will needs less watering.

So.. maybe a stupid question; how are people measuring GPM?  Quite honestly, *actually* measuring it would be a bit tough because the outlet is quite large and this time of year, there is a lot of water coming out.  I'd imagine it's a bit of guesswork given that we can capture the head, and the diameter of the outlet pipe and just guestimate how "full" the outlet is?

Overall, tho, even some of the sample numbers folks have thrown out, the wattage is fairly low, but, it's consistent day/night.

Agree on the temp solar panels; really pumping water out to a stock tank from the pond isn't going to be that power-hungry because it's relatively intermittent.  My stock rates aren't so high that we're going to be dumping more than a few gal/hour.

It sounds like your flow rate is very high and you can fill a 5gallon bucket in less than one second is this true?


The way to measure the flow rate out the outlet would be to put a container underneath it and see how long it takes to fill it. If you can fill a 5gallon bucket in half a second, you would then be able to fill 600gpm (2 * 5gal/sec * 60sec/min).

Due to the seasonal variability of solar/wind/hydro can you give the average for the specific season/month when you would visit.

Also, if you don’t mind using the metric system then the unit conversions are simpler.  

Power in Watts = Liters of water per second * meters of vertical drop * 10 * efficiency(between 0 and 1)