Author Topic: The bare basics of home energy production  (Read 903 times)

Sjalabais

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The bare basics of home energy production
« on: November 09, 2021, 07:34:42 AM »
I wonder if I could heat a tiny building with this one, and bring some LED lights to another building with this item connected to a tiny but steady water source next to it. I've been thinking about this forever, but I am slow on the uptake, have few occasions to sit down for longer periods and learn on my own, and forget easily. Basically a 40 yo with the attention span of a 5 yo, sometimes at least. My hope is that someone brighter than me could elaborate on how to:

1. connect lights and heat to a DC current power generator
2. protect a wind turbine with maximum speeds of 50 m/s from breaking at higher winds (will I need to physically take it down?)
3. can a system like that work with no power saving/feeding unit (battery or grid) - direct production, direct use? Can it produce too much energy/more than used and break?
4. possibly convert it to 220-250V AC/DC to connect ordinary appliances (I am in Norway, my household runs on 254V IT nett)?

There's so much that I just don't know, I am sure there are a lot of possible problems I am not even aware of. If anyone can recommend a good channel/website for learning the very basics, I am all ears.

secondcor521

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Re: The bare basics of home energy production
« Reply #1 on: November 09, 2021, 07:56:21 AM »
Paging @Syonyk.

Sjalabais

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Re: The bare basics of home energy production
« Reply #2 on: November 09, 2021, 08:05:56 AM »
Appreciated! If I could plug the wind turbine directly into an inverter, or even just a "sine wave converter" (whatever that is) and run a heater and lights off it, would be great. Alternatively, connecting a 24 or 48V DC heater with a fan directly to the wind turbine, ideally one that is tolerant to shifting power output...? I don't understand what could wrong and would rather not burn down my boat house or hidden-cabin-in-the-woods.

gaja

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Re: The bare basics of home energy production
« Reply #3 on: November 09, 2021, 08:39:30 AM »
You don't ask for regulations, but I'm going to describe them anyway: These small wind mills fall under the "flag pole" rule, and you are free to set them up anywhere. But for the hidden cabin in the woods some people might react negatively. For the water, the rules date back to the old Viking laws, that basically say that "all water shall flow, as it has from ancient times". So even a tiny power system in a tiny creek might be subject for regulations. This page has a lot of useful information: http://www.fossingkraft.no/Mikrokraftverk-Minikraftverk.htm

I know one old farmer on the west coast who built both a windmill and a tiny hydro power plant. The windmill fell under the flagpole rule, so he had no problems, except that the investment costs never paid back. For the water power plant, it was a bit larger than the one you are looking at, but he got around the rules because it was under the threshold value, and because he used the foundations and water roads for an ancient mill. That way, his hydro power plant wasn't a new intervention, but rather renovation of an existing structure.

Why would you use electricity for heat, and not solar heat or wood?

You don't need a large or expensive battery array, but a small one will solve a lot of what you are thinking about (fluctuations, conversion to 220 V, etc). The cheapest solution are old fashioned boat batteries.

Sjalabais

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Re: The bare basics of home energy production
« Reply #4 on: November 09, 2021, 09:46:57 AM »
Thanks a lot for insight into local rules! I even have a flagpole at the house which I was considering to convert to windmill use, as it is placed perfectly. This idea here would just be a test run.

At the cabin, I am only thinking about the tiny water turbine, mostly for light, and it would basically be invisible.

The boat house windmill could produce electric heat where I would normally not spend a dime on heating. There's a wood stove for smoking fish and meat, but the heat gets lost quickly. I swim in the fjord all year round and with the wind and cold now, just the tiniest extra heat, already available without preparation, would be welcome there.

The investment of about 3k NOK would be quite substantial given that it reflects about three months worth of our electricity bill, but I figure for a fun project, and bonus heat, I'd be in the black after 3-4 years, maybe? Expecting up to 20 years of free-ish electricity from this product with proper maintenance. The water turbine will probably only last a few seasons.

Cadman

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Re: The bare basics of home energy production
« Reply #5 on: November 09, 2021, 10:47:58 AM »
After a quick glance at the links you've provided, I'm afraid you'll ultimately be disappointed. These low voltage generators are fine for LED lighting, and even running some electronics in an off-grid situation, but you will need a battery bank regardless. This could be as simple as a single 12V deep cycle or an array of golf cart batteries. The amount of power you intend to draw would be dictated by the size of the batt bank, and the wind generator you chose would be a function of how quickly you need to recover that power.

Keep in mind batteries do eventually wear out, and you never want to draw a batt down below some minimum (dictated by the battery tech) so that should figure into your calculation.

At least one of the photos shows a controller with automatic braking current to protect the generator if voltage exceeds a certain threshold. If the controller fails, then all bets are off.

Trying to get electric heat out of such a setup isn't really feasible without long recovery times and killing your batts.

Sjalabais

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Re: The bare basics of home energy production
« Reply #6 on: November 09, 2021, 10:58:41 AM »
Thanks for the insight, Cadman! So a direct setup with, say, a 12/24V heater and a light bulb or two, just using the amount of power that is supplied directly, cabled to the windmill, would not work? So the stuff on this tiny network would just use the amount of power that is available, assuming e.g. the heater doesn't stop working at too low power levels. I mean, this is about cost, but also about simplicity and ecology. Deep cycle batteries are expensive here, and I just delivered what I had of 12V car batteries to the recycling center...getting a used EV battery would be nice for the house later (our Leaf is a candidate for that which is already parked outside). It's cost prohibitive for a project like this though, and these batteries are 400V, which would open a whole new can of worms if I even understand the consequences of that somewhat.

Syonyk

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Re: The bare basics of home energy production
« Reply #7 on: November 09, 2021, 11:14:09 AM »
I wonder if I could heat a tiny building with this one, and bring some LED lights to another building with this item connected to a tiny but steady water source next to it.

You could, but it's unlikely to work very well, won't generate much power, definitely won't be worth the cost.

The wind turbine suffers from the usual problems of small wind turbines, which are "They don't produce much power until they're about to blow down, at which point they shut down from protection."  I think the Chinglish talks about the controller being able to brake the turbine to prevent it coming apart from overspeed, but I'm not sure how that works.  The older stuff needs diversion loads that can soak the full power from it, I'm not sure if the tiny Chinese junk will self brake effectively or not.  I've no interest in them, because:



What's an honest wind profile of your place look like?  15mph is a decent breeze, and they make 50W.  By the time they're making rated power, 30+mph winds, you've got some serious wind going on.  And at some point above that, it needs to shut down for protection or it'll come apart.

The "20 year service life" for something like that is heavily based on "We won't be around to complain to when it does fail."  I would be stunned to see one of those last 20 years without failure.

The little hydro generator also won't last very long, and doesn't produce much power.  Plus regulations about waterways.  I'd expect it to last a week or two in free water, maybe more, but probably not much more.  Micro-hydro is a thing, and there are plenty of little off grid places with small hydro plants.  They don't look like that, they look like a proper turbine with (again...) diversion load controllers to soak the output so they don't overspeed if the batteries are full.

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I've been thinking about this forever, but I am slow on the uptake, have few occasions to sit down for longer periods and learn on my own, and forget easily. Basically a 40 yo with the attention span of a 5 yo, sometimes at least.

Then energy projects aren't the projects for you.  There are a lot of things you have to understand, keep in flight, and take into account.  The good news is that none of the stuff you've linked is likely to fail catastrophically in a way that would damage other stuff, it just won't last very long and won't do what you want.

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1. connect lights and heat to a DC current power generator

Depending on the nature of the output from the turbines, just hook them up, or you may need current regulation - the windmill lacking anything resembling a datasheet means I've no idea what it will do in various conditions, but "It will be unreliable at est unless you want to use a 600W turbine to run 5W of lights" would be my guess.

Heat, forget it.  It won't produce enough to be useful, and getting stuff dumped into a sane set of load resistors... you'd have to understand the output profile of the turbine or charge controllers, which you've got no data on there.  And more trouble than it's worth.  And you don't really want to be leaving 600W of thermal load unattended.

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2. protect a wind turbine with maximum speeds of 50 m/s from breaking at higher winds (will I need to physically take it down?)

50m/s is 112mph.  Is that actually an issue?  And do you trust that it will actually stand 50m/s without coming to pieces?  Again, it depends on how you're regulating it.  There are various ways of doing it, and I don't know what their controllers support, and I sure wouldn't trust a Chinese charge controller to properly handle it.  You can short the windings and gain a good bit of braking, you can offset the pivot point so it automatically cocks away from the wind under high speeds (the Otherpower designs do this), or you can hope it doesn't happen.  Without specs and details, hard to say what would or wouldn't work.  Sorry.

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3. can a system like that work with no power saving/feeding unit (battery or grid) - direct production, direct use? Can it produce too much energy/more than used and break?

It depends on how you design it.  You can make that sort of thing work if you use radically less than the system can produce, but it's quite challenging.  Do you really want the lights flickering on a low wind day?  As for too much energy, again, it depends.  But I wouldn't leave a turbine of any sort fully unloaded, that is a good way to have them come apart.

Rotary machinery for off-grid power generation is an awful lot more complex than solar panels, where you don't have to do anything special.  If you wonder why off grid systems don't seem to be using wind or hydro as much, it's because in almost all cases, with the cost of solar so low, you'll have a far easier time of it with solar than you will with the others.  Some people still build their own wind turbines, but consider that a "useful hobby" as opposed to anything sane at this point.  Back when solar was $10/W, yeah, small scale wind made sense.  At $0.50/W, it doesn't.

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4. possibly convert it to 220-250V AC/DC to connect ordinary appliances (I am in Norway, my household runs on 254V IT nett)?

No.  Now you're dealing with battery storage, inverters, grid tie interconnect agreements, whatever electrical codes are over there, etc.  That makes no sense for 50W of power.

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There's so much that I just don't know, I am sure there are a lot of possible problems I am not even aware of. If anyone can recommend a good channel/website for learning the very basics, I am all ears.

I'm sure you'll find plenty on YouTube.  I won't recommend any because I can't stand video for learning.  Be aware that for most of what you hear on YouTube, 90% is fine, 10% is badly wrong, and unless you're already an expert in the field, you can't tell the difference.

So a direct setup with, say, a 12/24V heater and a light bulb or two, just using the amount of power that is supplied directly, cabled to the windmill, would not work?

It might.  It might not.  What happens when the voltage drops because the turbine isn't producing enough power?  Those things are a fixed resistance coil and fan, and as voltage drops, you'll get less heat... but at some point, the fan will stop turning.  And the heater coils will still be producing heat - not much, but still more than enough to cause problems if they're not cooled.  You could add a battery into the system to hold 12V, and toggle it on/off, but you're adding cost and complexity to do that.  Electric heat from renewables is hard.  I do it in my office, but I've got 5kW of panel hung on my environmental disaster of an off-grid office. :p  It's a third of the house system, for one shed, and right now, in the rain, I have about 150W coming in, 400W going out.  It's an interesting system to play with, and it's nice having standalone power, but I don't pretend it's cheap, or particularly environmentally friendly, beyond "My emissions for incremental kWh as long as I've got good sun are zero, all the emissions are from production of the stuff, and I could stand to replace the batteries in a couple years."

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I mean, this is about cost, but also about simplicity and ecology.

It is an expensive, complex, and environmentally questionable way to accomplish what you're trying to do.

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Deep cycle batteries are expensive here, and I just delivered what I had of 12V car batteries to the recycling center...

Car batteries don't work for stuff like this.  They're not deep cycle.  They're SLI, designed to be discharged 1-2% starting the car, and then charged back up.  Deep cycle them, they have a lifespan measured on your fingers.  I typically consider a car battery good for about one deep discharge and recharge, the second deep discharge is time to replace it, it won't start a car anymore.  It matters a bit less for LED lighting, but they don't have a good lifespan when reasonably cycled, because they're not designed for it.

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...getting a used EV battery would be nice for the house later (our Leaf is a candidate for that which is already parked outside). It's cost prohibitive for a project like this though, and these batteries are 400V, which would open a whole new can of worms if I even understand the consequences of that somewhat.

400V and potentially thousands of amps short circuit current, yes.  Don't screw with them if you don't know what you're doing.

============

Sorry, not trying to be a jerk, but standalone energy systems are somewhat complex, and have interesting failure modes you have to reason about.  You can get cheap kits that claim to do stuff, which they mostly wont, or you can design it properly, but that's neither simple nor (usually) cheap.

Sjalabais

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Re: The bare basics of home energy production
« Reply #8 on: November 09, 2021, 11:46:50 AM »
@Syonyk, thanks for taking the time to shoot me down, thoroughly, I probably needed that. 🤪 My short reply would be: Now the same setup with solar, then?

I live along a headland in a fjord with tall mountains, acting as an accelerator of wind flow - like in a tunnel. We always have wind. Sun though, we don't have it at all between oct-feb, blocked out by those mountains. In short, this is much of my reasoning for the wind turbine idea. The water turbine was more a thought of invisibility and little need for power in that particular place. I did not consider it particularly invasive if it could provide for lighting (mostly) and maybe occasional heat. The same conditions also mean we can get wind speeds of 120 mph, typically around Christmas. It's rare, but it happens.

My expertise is in an entirely different field than engineering and electronics, but I'd love to be able to set up a somewhat self-sufficient system with solar, wind, discarded EV batteries etc. Even if it takes me years to achieve just a basic understanding of these topics, I believe it is worth it starting somewhere. What I find on YouTube though is hard to assess, as you say, and there's a lot of search results that do not even cover what they claim in their description. It's a good way to learn how to fix your car, but it's probably not applicable as much to this topic.

Syonyk

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Re: The bare basics of home energy production
« Reply #9 on: November 09, 2021, 12:04:27 PM »
My short reply would be: Now the same setup with solar, then?

Solar is easier, mostly because you don't have to worry about unloaded panels, and they're a lot better behaved if you're drawing a fraction of their rated power out.  You can stick voltage-compatible LEDs on a panel and have light when the sun is shining... which does seem a bit pointless when you could just have a window.  They don't have the same failure modes as an unloaded turbine, though.  Stick them in the sun unplugged, they're fine.  Short them, unplugged, they're fine (shorting the windings will slow a turbine substantially, but now you're dumping whatever energy it makes into the windings, which can overheat - diversions loads don't have that same problem because they're external).  They're just a lot easier to deal with.

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I live along a headland in a fjord with tall mountains, acting as an accelerator of wind flow - like in a tunnel. We always have wind. Sun though, we don't have it at all between oct-feb, blocked out by those mountains. In short, this is much of my reasoning for the wind turbine idea. The water turbine was more a thought of invisibility and little need for power in that particular place. I did not consider it particularly invasive if it could provide for lighting (mostly) and maybe occasional heat. The same conditions also mean we can get wind speeds of 120 mph, typically around Christmas. It's rare, but it happens.

https://www.otherpower.com/otherpower_wind.html

Spider off that, because they know what they're talking about with off-grid wind, and won't BS you with nonsense claims.

https://otherpower.com/bottom_line.html is a good starting point from them.  That's the reality of wind power, written by people who have more experience in small scale off grid wind power than anyone else.  They've literally written many books on it.

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My expertise is in an entirely different field than engineering and electronics, but I'd love to be able to set up a somewhat self-sufficient system with solar, wind, discarded EV batteries etc. Even if it takes me years to achieve just a basic understanding of these topics, I believe it is worth it starting somewhere. What I find on YouTube though is hard to assess, as you say, and there's a lot of search results that do not even cover what they claim in their description. It's a good way to learn how to fix your car, but it's probably not applicable as much to this topic.

You can do it, but it will either be cheap and a toy, or capable and expensive.  I've got... oh, probably US$10k in my office system?  I haven't summed it up lately.  It's an entirely capable year round off grid system, with generator backup (or power trailer, I can use that too now), and I make my living on it, but it's not built around cheap Chinese parts either.

yachi

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Re: The bare basics of home energy production
« Reply #10 on: November 09, 2021, 01:08:26 PM »
That Hydro Generator is made for sitting in a tap water line, not free-flowing in a stream.  It's hard to figure out what the different pressures in their spec mean, but it looks like it takes a minimum of 0.05Mpa to make it spin.  So you would need a column of water 5 meters high to get that kind of pressure.

If you want to use something like a natural stream to get the water, you need to go far enough upstream that the land is 5 meters above where you're discharging the water.  This Hydro Generator would be barely spinning where you're using the water.

EDIT to add: to get to 80 Volts, it appears to need 1.2 MPa, this would require your water source be 122 meters above where you're discharging the water.
« Last Edit: November 09, 2021, 01:19:15 PM by yachi »

Cadman

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Re: The bare basics of home energy production
« Reply #11 on: November 10, 2021, 06:35:00 AM »
Thanks for the insight, Cadman! So a direct setup with, say, a 12/24V heater and a light bulb or two, just using the amount of power that is supplied directly, cabled to the windmill, would not work? So the stuff on this tiny network would just use the amount of power that is available, assuming e.g. the heater doesn't stop working at too low power levels. I mean, this is about cost, but also about simplicity and ecology. Deep cycle batteries are expensive here, and I just delivered what I had of 12V car batteries to the recycling center...getting a used EV battery would be nice for the house later (our Leaf is a candidate for that which is already parked outside). It's cost prohibitive for a project like this though, and these batteries are 400V, which would open a whole new can of worms if I even understand the consequences of that somewhat.

Syonyk has pretty much covered the finer points, but to your question about connecting your loads directly, the reason that won't work is that you need the battery for both regulation and to satisfy the controller. The charge controller provides a PWM square wave as its output- a resistive heating element wouldn't mind, but most DC electronics would, and if it's anything like a solar charge controller, the PWM frequency is quite low. However, the controller also samples the battery voltage to determine the amount of charge to provide and adjusts the PWM output accordingly. Without that feedback, it likely wouldn't function at all. I also see there is a quiescent current draw in the specs, so the controller is relying on the battery even when power is not being generated.

I also see 3 leads going into the controller, so it's safe to assume this is AC power being generated by the turbine. Ignoring the fact you lose braking without a controller, without rectification and regulation, this wouldn't do you much good, either.

One thing about solar and wind generation at 12V is that copper losses become significant as soon as current levels rise; to keep the voltage in a useful window (which is quite narrow at 12V), you need to step up your conductor size which can get costly. 24V and 48V would be better options, but then you also need series batteries to take advantage of that.


Sjalabais

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Re: The bare basics of home energy production
« Reply #12 on: November 10, 2021, 07:22:00 AM »
@Syonyk, again, highly appreciated input, thank you! I will check out those links.
@yachi, thanks to you, too, for clearing that up! 122m fall is a lot, so much so that it doesn't make much sense for this product. From what I see in similar offers and a few who show the inner workings of eerily similar designs, the "turbine" wheel itself may be made from some kind of plastic - not metal. That amount of pressure does not suggest it will last any amount of reasonable time.
@Cadman, that's a clarification that raises more questions, again. I just assumed the three leads would be +, - and grounding? Anyway, I see there are many "finer points" of electricity production that I just don't grasp right now.

This was a very helpful thread to me, thanks for everyone's time!