Ivan's Creek: Low-head hydro-electric power

[Integral]

Got a call from Ivan yesterday, seems the creek was flowing full. Here are some pics.

Here is the foot bridge he as spoken (writen?) of:
http://home.comcast.net/~integral50/scenery/bridge.JPG

Last summer the deer were bedding down under this tree:
http://home.comcast.net/~integral50/scenery/deer.JPG

Another shot of the creek:

http://home.comcast.net/~integral50/scenery/creek.JPG

[Astronuc]

Ivan, have you thought of a hydroelectric plant up stream? :biggrin:

[Ivan Seeking]

Ivan, have you thought of a hydroelectric plant up stream? :biggrin:
Avg min flows [8 months] : 30 CFS
Max flow : 300 CFS
Max Head possible : 5 Ft
Expected avg power production: 5KW
Dam :$3500
Gen and electrical :$2500
Turbine :Banki Crossflow < $1000
Pay back <3 Years?
Nope, never thought about it. :biggrin:
For perspective, that bridge is 4.5 feet above the creek bed, it has about a 20 foot span, and the water is moving at about eight to ten feet per second [surface, center of stream]. When we bought this place we thought that it was just a nice little creek. :surprised

If I ever do it I plan to use the power for heat with a variable load to ensure max eff of the turbine. The remaining heating coils could run off of line power as needed. Any excess power would be directed to a pre-heater tank installed ahead of the regular water heater. This way I can avoid all of the complications of having to produce clean, 60 Hz power. I could even go DC.

[Ivan Seeking]

Integral didn't want to cross the bridge. :confused:

[Evo]

Geeze, you guys have been getting a lot of rain lately, haven't you?

[Ivan Seeking]

I had to drive through two 'lakes' on the road on the way to work yesterday. :biggrin:

[Tsu]

Dang. That's ^ MY post. :grumpy:

i sure wish ivan would remember to log off my computer when he's done.... :rolleyes:

[Evo]

Dang. That's ^ MY post. :grumpy:
i sure wish ivan would remember to log off my computer when he's done.... :rolleyes:You know you could destroy his reputation, right? :biggrin:

[Tsu]

Oh, yes. :devil: It's my ace in the hole. How do you think I get my way as much as I do? :biggrin: And that's not even taking into account what I could do to him in the MENTORS forum!! :devil: :rofl: :rofl:

[hypatia]

Why thats a beautiful creek! I guess even creeks want to be a river, every now and then.

[Gale]

.......

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i thought this was a pitch for a new pf show about a teenage ivan and his exploits in a small town with all his hot friends who all sleep with each other at some point.

[Math Is Hard]

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i thought this was a pitch for a new pf show about a teenage ivan and his exploits in a small town with all his hot friends who all sleep with each other at some point.
LOL :rofl: That's the first thing I thought, too. That stupid theme song is stuck in my head now!

[chroot]

Wouldn't the installation of a dam end up producing a (potentially very large) lake behind it? Wouldn't this need considerable environmental study and collaboration with downstream residents and so on? I'm actually curious about the feasability.

- Warren

[Ivan Seeking]

Wouldn't the installation of a dam end up producing a (potentially very large) lake behind it? Wouldn't this need considerable environmental study and collaboration with downstream residents and so on? I'm actually curious about the feasability.

- Warren

If the dam were located near the foot bridge, the maximum head might be obtained by doing some dozing work down stream. At that point I have enough storage up-stream to accomodate the water level without backing up water on the adjacent property.

Since it is a seasonal creek and is known not to contain anadromous fish populations, and since I have water rights as it crosses the property, in principle I can do this with almost no regulation. I would need a good number of permits to start but most of those are really just a formality. However, a couple could be sticky, esp mainly when it comes to approval from the neighbors. The next property on either side [up-stream and down-stream] would have to agree to the installation.

Oregon really was encouraging low-head hydro for a while, and part of the economic feasibility was based on the 30% tax credit that was once available. This is not available any longer but I believe that there are still federal tax credits available.

Even though oxygenation of the water is problem with any turbine, apparently low-head systems escape most environmental regulation; presumably since the benefits are believed to outweigh the costs. Note also that by design, the electrical would be isolated from the grid, thus reducing the number of regulations and avoiding the famous $10K safety switch.

Of course the real key here in the backwoods is that you do what you want as long as you don't bother anyone. To tell you the truth, the county officials would probably have a heart attack if I walked in the office with the engineering plans. But for me the other key point is that my experience in the real world tells me that there are too many variables involved here to be certain of how it would work out, and I have never done this because in spite of the numbers, my gut tells me that I won't come out ahead on this one. I keep waiting for a change of heart.

Edit: If we had a five foot water fall I wouldn't hesitate [except perhaps due to cosmetics], but I suspect that maintenance of the creek bed would kill it. I need four feet of effective head or the whole thing falls apart. At that point the turbine's eff curve drops like a rock as it starts to function improperly, and getting those four feet is not only the hardest part of the job, the maintenance requirements afterwards are some of the greatest unknowns. It can be a very dynamic creek; as you can see.

[Gale]

LOL :rofl: That's the first thing I thought, too. That stupid theme song is stuck in my head now!

YAY for MIH!! i always feel silly when i go to a thread for the entirely wrong reason. but soon as i first saw the thread title, i went and downloaded the song...

"i don't wanna wait for our lives to be over!
i wanna know right now what will it be.
i don't wanna wait for our lives to be over!
oh will it be, yes oh will it be.... something... "

gosh that dawson was a cute guy..

[Ivan Seeking]

Btw, the really nice things about the Banki turbine are that it is easy to design and build, it can be made with inexpensive pipe and steel, and the flow is mainly laminar, so the oxygenation should be kept to a minimum.

[Integral]

http://home.comcast.net/~integral50/scenery/streamlr.JPG

The state of the stream today... Not nearly as exciting.

[Moonbear]

Wow, what a difference from yesterday! It looks all sweet and innocent today.

[tribdog]

I wish I could get invited to visit a nice place like that

[Ivan Seeking]

Here is a pic of the '96 flood - a 500 year flood! You can see the foot bridge just to the right. We had tree stumps that weighed at least 500 pounds, out in the pasture afterwards. Edit: All of the water that you see actually entered our property as a confined flow in the creek bed, then over-flowed and spread out from there. It was a sight to behold. S.W.A.G.: 2000 CFS

Then a similar shot to Integral's, in the snow.

The creek is really cool and it has entertained the hydraulic engineer in me for many hours. Having a place like this is no small challenge, especially for a Los Angeles city-boy like me, and there are many negatives as well as positives, but the creek is a big plus for sure. We do love it.


http://img13.imageshack.us/img13/3487/floodsandsnow3fi.jpg

[Mk]

I have a creek down in Florida (or used to), it was very nice to sit on the deck and watch the water. But you know what, that winter picture of the creek blows mine away. Its so beautiful. :)

[zoobyshoe]

Btw, the really nice things about the Banki turbine are that it is easy to design and build, it can be made with inexpensive pipe and steel, and the flow is mainly laminar, so the oxygenation should be kept to a minimum.
I did a little googling on this, and it does look easy to make. Do you know how to weld? That's one thing I never managed to pick up that you would probably need to make this kind of turbine.

[Ivan Seeking]

I did a little googling on this, and it does look easy to make. Do you know how to weld? That's one thing I never managed to pick up that you would probably need to make this kind of turbine.

Since it wouldn't matter if it was a big ugly mess, I could weld it. :biggrin: I was pretty good on arc and acetylene welding at age 18, but now it would take some practice.

Due to the fact that they are a double impulse turbine, the Banki turbines can be surprisingly efficient. I found an old Master's thesis at OSU that goes through the entire design process, and their unit tested as I think almost 70% efficient.

[tribdog]

I remember you talking about some guy who was building a paddlewheel to power his home and you didn't have the heart to tell him he just flushed his bank account into the stream.
Do you know this stuff because:
a. it's part of your job
b. you have a stream in your backyard so did research
c. you know everything

[Ivan Seeking]

I took a minor in hydraulic engineering and then continued to study this because of the interest in generating power.

I know nothing, but at least I know that I know nothing, and that's something. :biggrin:

[tribdog]

false modesty makes me sick

[Ivan Seeking]

false modesty makes me sick

Obviously not a Socrates fan...

[tribdog]

You know I'm only a fan of you.

[Ivan Seeking]

How much money did you want?

[zoobyshoe]

Since it wouldn't matter if it was a big ugly mess, I could weld it. :biggrin: I was pretty good on arc and acetylene welding at age 18, but now it would take some practice.
Due to the fact that they are a double impulse turbine, the Banki turbines can be surprisingly efficient. I found an old Master's thesis at OSU that goes through the entire design process, and their unit tested as I think almost 70% efficient.
Here's a guy who made a small one out of junk, and also made his own generator to go with it:

http://www.otherpower.com/scotthydro1.html

Sounds like he gets alot of power out of the little thing.

[tribdog]

How much money did you want?
5 dollars and 67 cents. Double quarter pounder meal. I'm hungry

[Ivan Seeking]

At three feet of head the first guy is probably off the power curve - the water falls too fast wrt to its forward velocity so the second impulse is out of time [I should say that the angles of the blades are wrong], which causes turbulent flow - but even then the efficiency can be as high as 50%.

[Ivan Seeking]

I moved this to engineering as a low-head hydro-power thread. There are times that this seems to be worth doing; esp here in the Pacific Northwest. In my case, the creek is probably too dynamic to tame for a 5KW, 8 month per year installation.

[Ivan Seeking]

Maybe this is being done now, but the idea of a variable load to match the source seem to be key with LHH. Consider electric space heat run in constant duty mode - say for example if we run 5KW at a 90% duty cycle, with a low speed fan mode [on the space heater], at opposed to the typical 20KW over a 23% duty cycle. This should allow space heat to run almost exclusively on hydro-power. Also, by adding the water pre-heater in front of the water heater, I calculated that we could utilize the average 5KW most of the winter with no other energy storage. IIRC, space and water heat are about 80% of a typical home's energy usage.

If you look at the average power usage in any home, it is surprising how little power is really needed if one could avoid the large, low duty cycle loads. Smart loads are I think a key concept needed to make this type of alternative supply practical.

[Ivan Seeking]

Okay, here is a nice page for the Banki turbine.
http://home.carolina.rr.com/unclejoe/

According to this, the paper that I read must have been the translated paper - Bulletin #25 - and someone at OSU built and tested it.

[Bystander]

http://home.comcast.net/~integral50/scenery/streamlr.JPG
The state of the stream today... Not nearly as exciting.

Have you considered the "rustic" approach? Can't tell a whole lot about the topography, just picturing an undershot wheel 'tween the trees and bridge, 'bout even w' the bar.

How much cutting goes on during the high water?

[Ivan Seeking]

Anything but a crossflow turbine is too inefficient to be worth doing. It just wouldn't be enough power to be useful in a practical way that would offset the cost. Undershot wheels can run as low as 20% efficient...in fact I think that's more like a best case.

And it does move an amazing amount of rock during heavy flows. The little island seen in the one shot was formed in about one day. I have seen it dig straight down through six feet of rocky clay in a week.

[Ivan Seeking]

I didn't even notice that the original paper is linked at the end.
http://home.carolina.rr.com/unclejoe/banki_scan.pdf

Also, ignore all of the whining about the paper. I had no trouble reading it and then designing my own turbine. [Yes, unfortunately I got that far].

[Ivan Seeking]

One more thought here: I think a major trap for the alternative energy crowd is the idea of selling power back to the power company. At $10K for the safety switch that is legally required in order to prevent back-feeding the lines during an outage and possibly killing a lineman, I don't think it's worth trying to sell the power back unless we are talking about a very large installation. But in many more cases it does make sense to isolate the system from line power and design the loads to follow the supply power available - to keep the system operating at max efficiency. The plan was to design one of the four heater modules [~5KW each] so that by using triacs, a 1, 2, 3, 4, or 5 KW load could be selected so as to maintain a nearly constant turbine speed. This seemed a best option as opposed to trying to PWM a highly inductive load or trying to vary the load linearly. In both cases the potential complications seemed best to avoid altogether. But this was a judgement call and unique to my situation. Linearly variable loads would probably work fine in most cases. The additional water heater element would be a fixed load in this plan, which would cause some additional losses, but it calculated out that those losses would be relatively small, and acceptable.

If the creek was more stable with an easily had four feet of effective head, and assuming a typical Oregon winter, this installation calculates out as being worth about $250 per month, eight months of the year. And keep in mind that a typical flow is about 16% of that seen here. Integral came by because of the unusually large flow due to a month of heavy rain.

Late edit [sorry]: for those who don't know this, one of greatest sources of energy loss and expense for alternative energy systems is the need for energy storage. This design seeks to avoid this problem. Also, the final parameters were for a variable 1- 10 KW load as the flows in the creek vary over the season. The max efficiency of the system occurs at a constant turbine speed and is otherwise independent of the load or the power being generated.