Engineering design makes all kinds of tradeoffs. Power trades off with torque, strength trades off with weight, and cost can trade off with quality. For designing a hydroelectric turbine, one of the main tradeoffs is hydraulic head with flow rate. Many large dams meant for bulk power generation will go with high head (or medium) designs, and for small dams with low head it’s usually not cost effective to build any generation. But if you’re really determined, you’ll want to build a low head water turbine like this one.
The build aims to use easy-to-find materials and simple tools. It uses 110mm and 160mm PVC pipe to not only siphon water up and over a dam, but to house the turbine as well. The turbine is built from a computer fan and sits inside the pipe with a shaft running through a Y-type fitting to the generator. The generator is built from a scavenged hoverboard wheel, and outputs a reported 3.3A DC at 60V for around 200 watts of power with only around 3m of head. The design allows the turbine to be placed at the point in the pipe that best suits the environment.
[OpenSourceLowTech], the creators of this project, make a compelling case that this build is cheaper than a 150W solar panel and it might even be able to produce more energy as well over certain timeframes, provided there’s a reliable source of water available and the owners of the dam don’t mind someone siphoning water over it continuously. The build video is worth a watch as well if for nothing else than the animation, which documents the build in excellent detail. Generating usable energy from hydropower doesn’t even need this big of a dam; if all you need is to charge your phone this tiny waterwheel will get the job done.
Thanks to [Keith] for the tip!
“for small dams with low head it’s usually not cost effective to build any generation.”
Turbulent disagrees. their turbines generate reliable electricity, typically ranging from 15 kW to 70 kW per unit—requiring a height difference of only 1.5 meters
15-70kw is enough to power 9-60 average american homes given the 24/7 potential of hydropower.
Their 15kw system costs $60-80k installed and has an expected lifespan of 30 years. That works out to around $25/mo per household in the worst case scenario.
At 70kw the cost rises to $300-350K installed. Thats good for 40-60 average american homes.Thats $14-25/mo per household.
They can even chain multiple turbines in series if there is enough drop across the property the water flows through.
Don’t forget to check out Farm Craft 101’s channel where he built his own turbine from 3D printed parts, a rewired alternator, and lots of heavy farm equipment to handle the excavation – including jack hammering gneiss bedrock.
Without mentioning the amount of water going through this, nothing can be said about efficiency.
But 3 meters is enough to get some real usable power. For example the link below squeezes 28kW out of a head of just 2.5 meter.
https://nl.wikipedia.org/wiki/Apeldoorns_Kanaal
This one gets 2kW out of a head of 2m It’s also an 150 year old museum piece (apparently there were water wheels in that location for over 700 years now).
https://nl.wikipedia.org/wiki/Spoordonkse_Watermolen
And of course, here in the Netherlands, (nearly) all hydro power is “low head”, as the whole country is pretty flat. There is a list of over thirty hydro power installations in the Netherlands in:
https://nl.wikipedia.org/wiki/Lijst_van_waterkrachtcentrales_in_Nederland
“Generates Plenty Of Power” Uh, I don’t see how 192W is plenty of anything