Since childhood I have always enjoyed playing in streams, and am fascinated by flowing water. Flowing water has power. Falling water has even more power.
Where I live, there is a relatively small seasonal stream, with a tremendous elevation drop — 500 ft from summit to base. Even just a few gallons of water falling this distance will generate meaningful power, enough to run a house! (Albeit an energy efficient one).
My system started with the insulation of 1,000 ft of PVC pipe. This involved dragging 20 ft sections through the woods using a bungee cord harness (and the company of some good podcasts).
I then glued all the sections together and created a primitive inlet. Once I validated my system head (initially 35, later upgraded to 55) I installed an electric motor and Pelton Wheel from www.HiPowerHydro.com.
The next step is to move the power somewhere useful.
Having built a power generator, I had to transmit the juice a distance of about 3,000 ft. I choose to use what is considered “high voltage” direct current, about 100 V, which is produced by rectifying wild three phase alternating current at the hydro source; this allowed me to minimize wire usage, but over a distance of several thousand feet I still ended up needing 6 gauge to minimize loss. (My goal was to realize at least 95% efficiency in both piping and transmission wire, which is not the most economical choice, but the most aesthetically pleasing from an engineer’s point of view).
The spool weighed something like 400 or 500 lbs, and once I got it to the site I realized I didn’t have the appropriate equipment to unroll it. Since I was staring at the top of the hill, my most efficient option was to just roll it down the hill (I can be somewhat impatient). I pointed it in the right direction, and let go. This worked surpassingly well, though I did unfortunately destroy a number of sweet saplings. The wire also did not follow the most direct path, but it worked well enough for my purposes. Once up and running, my initial install produced between 50 and 400 watts of clean renewable power. At the high end, it produces enough to run a mid-sized energy efficient home.
Hydro power is great, because it's on “all the time”, meaning you can greatly reduce the battery bank size for an off-grid project. This also makes it very competitive with solar; running 150 watts continuously doesn’t sound like a lot, but it consistently outperforms a 1 KW solar array in the same area; and requires only a small battery system.
The stream I’m using has a very high fluctuation of water flow depending on the monthly and even daily rainfall (from 3 to 100 gallons per minute!). To compensate for this, I decided to give the system the ability to actively respond to changing water conditions. (I thought this would reduce the time I spent hiking up and down the hill to turn valves on and off or switch nozzles, but in the end, I suspect it stayed the same, or even increased, because the ability for things to break increases geometrically with your system complexity). Fortunately, I like hiking.
The first thing I did was add some aquarium float sensors in the stream to determine the water level and turn an electrical ball valve at the bottom of the hill on or off. This worked out okay, until the system was struck by lightning. It was also somewhat susceptible to debris and frogs.
I then moved to a very sensitive pressure sensor I found on ebay and used that to measure the height difference in the stream; but this turned out to be difficult as the resolution needed at the base of a 50 PSI system to detect a 1” or 2” of water level change is very high. Through the use of a custom op-amp I was able to accurately gauge these changes, but temperature fluctuations would throw off my calibration leading to stupid system behavior (and more hiking).
Most recently, I settled upon what I think is the most elegant solution, using the hydro motor itself as the sensor. The power output varies directly with water pressure which is a function of stream height (which relates to flow rate in a constricted section). I’m able to measure the amperage on the electric motor output accurately enough such that I can predict when water flow is dropping or rising and open or close 1 or more valves.
The brains for this system is an ArduinoUNO; I use a European wall wart to convert 1 of the wild AC phases put out by the motor into 13.5 V DC, which powers the UNO and also trickle charges a DC battery.
I also use the UNO to switch valves on and off if the water flow rate is in between the various nozzle sizes available on the hydro. This enables me to capture 100% of the water flow at the highest efficiency possible. (Different nozzle sizes have different efficiencies, so the one that is calibrated to your stream's flow, may not be the most efficient.)
Most recently I’ve added SMS capability to my project, so I can manually actuate the valves, increment the duty cycle, and also query the sensors. This has proven to be very helpful, but is embarrassing when I accidentally text folks things like Valve 1 ON!
I’ve included the code for this project below:
You are welcome to use or modify as you see fit; it's good starter code for anything you might want to actuate remotely using your mobile phone. Please note, the original file is .ino rather than .txt. This is called a “CrayFish Error''.
Later on I had a “Frog Error” which was very sad. Since then I’ve installed a much better screen on the inlet to protect curious frogs (though I suspect the first 4.5 minutes of the ride down the pipe must have been a lot of fun for the frog!)