For economic reasons, not every lake with a dam can support a hydroelectric power plant. Some rivers or creeks are dammed for flood control or simply for recreation, and don’t have the flow rate or aren’t deep enough to make the investment of a grid-scale generation facility worthwhile. But for those of us with a few spare parts around and access to a small lake, sometimes it’s possible to generate a usable amount of energy with just a bit of effort.
[Beyond the Tint] is building this mostly as a proof-of-concept, starting with a 1,000W hub motor from an e-bike that’s been removed from its wheel. A 3D-printed waterwheel attachment is installed in its place, and the fixed shaft is attached to a homemade ladder-looking mechanism that allows the entire generator to be lowered into the flow of a moving body of water, in this case, a small stream. A bridge rectifier converts the AC from the hub motor (now a generator) into DC, and after a few measurements and trials, [Beyond the Tint] produced over 30W with the first prototype.
A second prototype was made with feedback from the first video he produced, this time with an enclosed paddlewheel. This didn’t appear to make much difference at first, but a more refined impeller may make a difference in future prototypes. Small-scale hydropower is a fairly popular challenge to tackle, especially in the off-grid community. With access to even a small flowing stream and enough elevation change, it’s possible to build something like this generator out of parts from an old washing machine.
Great project but cant help wondering how long before water gets into the hub?
Agree. Few weeks. But hey, we all have to learn some somehow and mother nature is a good teacher.
It will run flooded because its a brushless motor.
However the bearings might not like the water.
More importantly how long until the local department of ecology fines idiots for daming streams trying to be “green”.
Nobody is even going to notice the amount of water diverted to run a tiny wheel like this, nor the tiny dam you’d perhaps need/want – great you created a duckpond…
A dam really isn’t going to harm the local ecology when done on these sort of scales, you flood or maybe just make boggy a small patch of ground and make practically no change to the path, volume of flow etc of the river – any difference you have made is going to be lost in the noise of natural variation. If anything that tiny patch of permanently wetter probably helps the local ecology as far to many of our rivers are highly engineered and flow too darn fast keeping the local area drained rather more than nature intended.
Numerous small dams have tremendous effects on river ecosystems. They change everything from how fish migrate to how much silt is carried downstream, what types of algae or insects live in the river etc. Fish may get up one dam, but when there’s 20-30 more up the stream, the proportion that gets through to the breeding grounds becomes smaller and smaller, and the variety of fish and other organisms that live in the river becomes less. Biodiversity suffers.
The flooded areas behind the dams also cause troubles because river flows change, so these areas become not permanently bogged but areas where the water levels change from year to year, causing sedimentation of biological matter that starts to rot, which deprives the water of oxygen and releases methane and nutrients downstream, leading to algae blooms and fish die-offs etc.
Lately there’s been more and more focus on tearing down all the unused old mill dams that dot all the small river branches across different countries. They’re restoring the rapids and seeing an marked improvement in water quality and the number of fish species that travel further up the river etc. It has a human impact as well: with cleaner river waters, cities can start picking up drinking water off the rivers and lakes with less filtration and purification, reducing the drain on dwindling deep ground water resources.
Well if he got it out of an actual E-Bike maybe he could use the chain to keep the hub out of the water?
yes, but the chain doesn’t like water and the water doesn’t like chain oil
The motor can do about 2kW at 800 rpm. He is doing about 100-150 rpm. A faster spinning turbine can improve his results a lot. I estimate that his stream has about 700 W of energy. Extracting about 50% of that should be possible.
“can do about 2 kW” means it produces 2 kW of mechanical power, or actually requires 2 kW of electrical power? Because at peak power an electric motor is not very efficient: you can expect half the input electrical power to end up on the output shaft.
And I’m pretty sure you meant to say “700 W of power“, because saying “700 W of energy” is nonsense.
Its a brushless motor so about 95% efficient both as a motor and alternator.
Not even wrong.
A vortex turbine might be a good choice here due to the low height difference.
Might need a different generator due to the lower speed.
But…its fish friendly, and very resilient against floating debris.
Good luck, like this!
As a kid I had a tree fort waaay out in the woods on my grampa’s land. There was a fairly large creek that ran nearby with a small waterfall. My dad and I built a hydro generator and battery storage system, and that was enough to operate the electric elevator we also built to get into the tree fort and of course some lights. The hardest part actually was treking tools and materials that far into the woods. And if we had to cut or drill something that required serious power, we had to trek it back to the house then back to the fort. Lithium batteries and cordless tools weren’t a thing back then, nor were cheap gasoline powered generators.
It always baffled me that these weren’t on every waterway.
Economics, plus it’s hard to make them fish friendly. Making a water turbine that is low maintenance is the really hard part. If you’re having to send someone out every few months to fix it, that rapidly makes these things not worthwhile. That’s why solar is so popular for small scale power generation – you can’t beat solid state for reliability.
You don’t need much flow to make it work. Small diameter pipe makes it fish friendly, then your problem becomes keeping the intake debris free…trade offs….
It’s a good thing they aren’t. Dams destroy river ecosystems.
Tell that to beavers 🦫
Beavers destroy plenty of habitat I assure you.
Beavers create plenty of habitats
Don’t bother, they won’t give a dam.
Yet you like to use the power they produce
Not much point crying over spilled milk if you can’t do anything about it.
Hydropower isn’t really the sustainable option it was sold as, and on the larger scale they are actually quite hazardous, especially the huge dams starting to reach a hundred years of age, getting neglected by governments who don’t want to allocate any funds to maintain them.
Hoover Dam – couldn’t get the environmental or human risk approval if you were to build it today.
That’s only true for really big dams. Small weirs for around 1 .. 10kW are ok for most fishes, and sometimes they limit the big, hungry fishes to the lower side, protecting the smaller water habitants on the upper side. Additionally the weirs can provide survival water pools during droughts. (Sorry for the language, my vocabulary lacks some special words here.)
Big dams have fish ladders and have the ecosystem taken in mind when designed. Joe idiot who just want to boast about charging a lithium ion battery won’t consider it
Dams ALTER the ecosystems.
They do not DESTROY the ecosystems.
I live 60 miles west of Asheville, NC.
My area got the same wind and rain from Hurricane Helene.
We have dams for hydro power, recreation, ag irrigation and flood control.
Their environmentalists blocked a 1966 proposal.
They flooded, we came out unscathed.
Same as how a huge monoculture industrial farm doesn’t technically destroy an ecosystem it replaces – it merely changes it, often irreversibly.
These can be added to navigable rivers in place of weirs that accompany locks with minimal changes to the ecosystem. Archimedes screw turbines allow fish to migrate up and down stream. Often the drop and water-flow are too small to generate enough power to recoup the original investment, better renewable energy sources are often available.
Have you seen the way Turbulent does their micro hydropower systems?
Rather than dams they run a diversion channel to send a portion of the waterways flow through their whirlpool genset then dump the water back in down stream. They have systems from 5-100kw which might not be huge, but their small size allows multiple units to be installed along a waterway for higher output requirements. https://www.renexusgroup.com/wp-content/uploads/2022/01/energy-banner3.jpeg
So, like Niagara Falls. They divert only some of the water during the day to run it through the turbines. When the tourists go to sleep they turn off the lights illuminating the falls, and divert much more, basically turning off the falls at night. Much of that water gets pumped into storage reservoirs to use during the following day.
Not really these arent a throttled drain capable of stealing the entirety of the flow. Theyre much simpler. Smaller scale. Micro Hydro. They say fish can just swim through them, though I imagine thats only true to a certain size. In any case, they are closer to what Garreth implied, systems capable of running on almost any waterway with minimal impact.
https://youtu.be/XiefORPamLU?si=iZhzx0dt2Scbc2QC&t=25
Very cool! Kreosan-esque.
Wasting the energy from the fall with the wheel at the top, the turbines in a dam are at the bottom for a reason. Even that foot or so height is potential energy.
Yea the commenter’s were stupid. It needs to be a tube going down into a impeller. Not a water wheel at the top. Water wheels are just for water moving sideways. Water falling has much more energy.
May be a good idea for keeping this rather fragile small wheel intact, and making darn sure the water only ever hits on the correct side – lower the wheel and at greater flow rate the water can be hitting both sides or even only the wrong the side of the wheel if it is dropped down…
Also no point in dumping more energy onto the wheel if it can’t actually use it. So yes you are correct extracting as much of the energy from drop distance would in theory produce more, but in practice…