Hydroelectric turbine providing power to our off-grid house

[schweizer]

Here's what I worked on with my tractor on Friday afternoon:

1st some backgroundd: We live off-grid -- not connected to utility power at all. In summer there is plenty of power from solar panels. In fall and winter, things are not so nice. Lots of rain and overcast. We have to charge batteries with a Lister diesel generator when the sun's not shining. (Some of the time I burn old waste engine oil in the generator which offsets diesel cost.) There is a steep little seasonal creek around the corner from the house, which just started running again. Last spring in May, just before the creek dried up, I installed a hydroelectric turbine.

Over the past week, we had 10 inches of rain. The culvert at the intake screen got clogged from debris. The whole intake system then got washed out on Wed. night. Luckily the expensive stainless steel coanda screen didn't get washed down the creek because of some strategically placed cables I had installed last year. Time to redesign.



After getting the culvert unplugged, but just a few hours before it washed out:

On Friday afternoon, with a lot of tire spinning in 4wd I finally got my Kioti w/ backhoe up to the intake area. First, I dug a new settling pool to about 3 ft deep and used the spoils to make a new mini-dam. Tried to use as many boulders as possible. Then, instead of placing the coanda intake screen under a culvert, I placed it at the lowest point along the dam. Now, when the water rises hopefully it will just flow deeper over the screen like a normal spillway. The mistake was using a culvert for this application.











Have a great day everyone!

Marcus

 

[schweizer]

Youtube clip of the turbine:

 

[Tractor Seabee]

I am looking into using hydro power at my place. I am on the grid but need to cut power cost as we are all electric. I have a year round creek with good flow. I would put the intake at the upper property line, 75' above where the house is and piping down then discharge back into the creek 15' lower yet for a 90' head. As I have constant flow I am wondering if I can get a 220V alternator and feed direct AC onto the grid w/o messing with DC, battery bank, and inverter. All that extra hay makes the payback a lot less attractive. My rough estimate so far is 5-7.5 KW using a 4" penstock. Idaes any one on that scheme, anyone done it? I will have to bootleg it all in as the permitting process here in WA would probably never get approved.

Ron

 

[schweizer]

Notice I have not said anything about the permitting process. Suffice it to say that the company I bought my turbine system from says almost all the systems they install or sell are NOT permitted because of the onerous nature of permitting. We also have a year round creek flowing through our property, but it is close to a paved BLM road and it is monitored/patrolled regularly. After starting the paperwork and making lots of phone calls, I gave up on the permits for using a year-round fish-bearing stream even for non-consumptive use. What a pain. Note that I was careful to use a high quality coanda screen to keep out debris, fish, etc.

The generally accepted equation for expected watts output is: Watts = vertical head (ft) x flow (gpm) / 10 (assuming 50% efficiency)

Therefore, if you have 90' head and think you'll get 5 kw (5000 watts), you must have >500 gpm flow. That's a LOT of water for a 4" pipe! Not trying to dissuade you, but are your calcs correct?

What you have written is possible, but the problem with the setup you are contemplating is that the rpm of your turbine is going to be limited by the 240 V AC, and it would have to be locked in-phase with the power co. Normally, you use wild variable AC with these turbines. Also, if there is a power failure, you will be back feeding the power grid (!!!!). You'll need an automatic disconnect. Then, if you disconnect the load from the turbine, the turbine will overspeed and tear itself apart. There, are ways of doing what you want to do. Most involve using standard grid-tied inverters, a la grid-tie solar panel system, but without the battery bank. You'll need a diversion load also, which is relatively cheap.

Marcus

 

[Tractor Seabee]

Thanks Schweizer,

I have not gotten as far as you have on this. Luckily I am pretty isolated and there is large forested acreage all around. Even 1 KW would run my greenhouse loads. I have a generator transfer switgh but it is manual. An auto disconnect is simple though using a small contactor with the solenoid normall closed and a normall open valve in the penstock would stop the overspeed problem. Those are fairly cheap compared to a battery bank set up for load dump. I have a lot of research to do yet.

Run

 

[Gale Hawkins]

Marcus that is one heck of a nice project. Thanks for the details and keep us posted.

 

[ultrarunner]

Always like reading about your projects!

I visited a distant cousin in Austria... his family were Blacksmiths going back many generations.

The house they live in is very old and they heat the entire house with electricity from a small 7' water wheel... it doesn't turn fast, but is has a lot of power from the flow and the install was permited about 100 years ago... otherwise it would be a no go also.

All the power goes to heat water for domestic and heating... there are still the old overhead pulleys and belts in the shop that are water powered and no longer used...although he did a demo for me and it all came to life.

 

[schweizer]

there are still the old overhead pulleys and belts in the shop that are water powered and no longer used...although he did a demo for me and it all came to life.

ultrarunner: That kind of stuff is so cool! I'd love to see that.

a normally open valve in the penstock would stop the overspeed problem.

Ron: Yes, but it would have to close slowly because of the waterhammer effect. Even when I shut down the flow with a ball valve I have to do it very slowly. You can clearly watch big spikes in the water pressure on the gauge. I'm always worried about blowing out the black poly-pipe, or one of the joints. 90' vertical would generate about 36 psi, so you would probably be safe.

 

[ultrarunner]

Would it be feasible or necessary to add a captive air tank or hammer arrestor?

 

[schweizer]

Probably --- don't see why not. You'd want it down at the bottom near the turbine. I just put a T in the 2" penstock and installed a regular water heater TPR valve. If the pressure gets above 100 psi it should leak water. I just mentioned stuff like this because it's not as easy as putting in a penstock, turbine, and hooking up to the grid. I'm finding out the hard way that the intake is probably the most crucial and needs to be well designed.

I'm not an professional in this by any means, but I read a few books on it before attempting my own system. We came home tonight after a weekend at my parents house, and the system is producing only 10 watts. Hmm. Hope it's just a pipe joint that blew out somewhere.

Marcus