Syngas fueled generators have erratic performance problems and cant be directly connected to the grid. You have to charge batteries and then send that electricy to the grid via inverter iust like solar panels. Gasify away.
1 Like
I’m not sure if you’re asking something, or making a statement, but I’ll take a chance. I’ve done it, very small scale, with an induction (asynchronous) motor, but only with gasoline, not syngas. But there are others way ahead of me:
4 Likes
Are you asking ChatGPT those questions? If so, there may still be some hope for humanity. If it says it cant be done, there is a couple of proofs of opposite just on this site.
6 Likes
Kristjan, I’m with you. The operation of an ASYNCHRONOUS generator powered by a wood gas engine is the simplest thing that allows operation with the network. The wood gas engine should be connected to the generator with a one-way clutch, so you can easily start the asynchronous motor (generator) with the mains and it can idle smoothly, when the wood gas engine reaches these revolutions, the one-way clutch will engage and it will spin asynchronous motor via mains frequency, which starts working as a generator,…
9 Likes
This is how. I get paid by Nordpool electricity spot price.
Using woodchips with an epic Chinese heavyweight (306 kg) JXQ-10A gasifier with Ducar off-the shelf 7.5kW generator + simple carburetor inlet mod: 1-phase 220v AC electricity is rectified into 250+v DC, fed into Growatt inverter 2nd input (1st for my 4kW solar), converted to 3-phase 400v AC, utilized for my household, and the surplus sold to the grid.
12 Likes
So In case it was a question and not a statement. I believe the consensus is the easiest was to feed gasifier power to the grid is to use a battery based Hybrid inverter that can send back to the grid as your go between. Charge your batteries up and once they reach the “sell” voltage it will ship out to the grid. I like the rectifying and feeding into the pv input that looks slick. When I was pondering all that out I tried it using a second obsolete off grid inverter for its battery charger and fed it into the same battery bank as the grid connected inverter. I know an asynchronus induction motor would also work but that is before my time. iBy the time I started playing with all this It was all digital. If you are operating in any of the areas with digital power meters they will throw fits if you just start feeding them power without a signed and approved agreement with your utility. You could get away with it in the analog meter days and maybe some people still have them but here and most jurisdictions that I know about it is much more controlled then that. Signed agreement, approved gear, inspected installation replacement 2 way meter. I don’t think its worth it myself better to create a dedicated system that feeds from the grid but runs mostly on its own energy.
Cheers,
David
13 Likes
My solar system was installed over 10 years ago when panels and inverters cost the earth , at the time i could only afford to have a 1kw system fitted , i have never seen anything near that from my old panels and wondered about converting ac gen to dc input on the spare lnput of my inverter , trouble is i just worry about messing with dc voltage of around 240 volts , but i guess its more or less going to be like ac current you wouldn’t wanna be playing with that anyways .
If Teemu could show me his rectifier or the component needed for me to build one i might have a go at doing mine as i am allowed 1kw an hour i may as well take advantage of that as i get almost 20% extra now on feed in .
Dave
4 Likes
Here is the setup of my rectifier box:
Pic 1: Core components: Reatifier and capacitator
Pic 2: The label of a heavy duty rectifier
Pic 3: Lighter rectifier, also works fine
Pic 4: The case
Pic 5: Digital display (and multimeter)
Some of my components are heavy duty, and my operational box has those; only wires need an upgrade if I go way up with the load.
The capacitor is that heavy because I found 4 of those for 5$ at surplus junk store. Much smaller will do. Also, the setup works without a capacitor; my picky inverter just needs 250+ volts DC, and because of the peaks coming from the generator the capacitor keeps the current above that level. Also, I guess that also improves the quality of incoming current.
The beauty of the setup is that everything touching the grid is professionally installed; I am just mimicking the input of solar panels and the inverter works as supposed. I even can monitor the power generation using inverter’s default app on my iPhone, and electricity sales from the online service provided by the grid operator.
You will get all the components from eBay, Amazon, or AliExpress for loose change. (I also ordered and tested much lighter and affordable rectifiers and they worked just fine with 2-3kW. See the picture.)
9 Likes
Because you are rectifying 240V single phase AC to DC, there is a zero voltage point when the phase crosses from positive to negative. This zero point is what is tripping up your inverter so the capacitor is needed to prevent the zero voltage point.
It is taking the energy from the ‘peak’ value which is more then the rated voltage. The capacitor is ‘smoothing’.
To give an actual picture (lifted from hvacrschool.com) … red and black are the two AC hot wires, and you see where they cross at 0V. You also see the voltage peak is 170v, but the effective voltage is 120v. Now put a piece of paper over everything under the Ov line in the chart, and the humps are the waveform of what you get as output from the rectifier. They touch OV. In reality, the humps are taller. So capacitor is adding current stolen from the peak to keep the humps from reaching zero, but it is still probably humpy looking if you looked at it with an oscilloscope.
Hopefully that makes more sense.
7 Likes
thanks Teemu,
forgive my ignorance but how do you control amperage in this setup? What limits the amperage of the input to avoid a breaker popping?
2 Likes
Can’t limit, just do the math. Let’s say, with a good batch I get up to 3kW at 260 volts = 11.54 amps. One must use components that can handle the load. Kilowatts (kW) to Amps Conversion Calculator - Inch Calculator
Furthermore, my inverter is intelligent enough to auto-break if something too odd (like wrong polarity, i.e. mixing + and -) tries to creep in: reset and reboot… and try again.
3 Likes
Very good explanation! Thanks. I did not know the inner workings of my box! My super-knowledgeable friend just suggested adding a capacitor to solve the problem of getting only up to 240V DC , a tad bit too low.
5 Likes
I’ve only skimmed through all the above. Maybe I missed something - but wouldn’t it be easier to just use a regular 3-phase motor? Same type used on your saw, woodsplitter etc. All you have to do is plug it in as you would if you were expecting it to do work for you. Only difference is you add a belt and let your ic-engine try force it to speed up. No reatifier/inverter gizmos needed.
I realise American standard is mostly 1-phase, but Teemu - you’re in Finland, right?
9 Likes
You are absolutely right: the easiest way is to use 3-phase generator and plug that in directly to the outlet. After installing and running the setup as described, I have purchased a 3-phase one for the reason you said. However, I haven’t bothered to try that, yet. The benefit of my “gizmo” (lol) setup is better monitoring and the seamless function in parallel with solar panels. If someone does not have solar system installed, it is easiest just find a proper generator and cable (so-called “killer cable”), and make a contract with your grid/utility company. There is nothing different from a standard backup generator use, except your fuel.
I am in Finland, yes, and a typical household has a 3-phase power coming in.
8 Likes
Teemo, I have solar and the motor/generator’s production is easily monotored via the solar app - just saying. Only problem is that I need Finnish electricity prices to justify gasifier lightup 
8 Likes
It was several thousands in ‘engineering fees’ plus all the wiring for connection fees to get a 3-phase motor hooked to the grid in the here in my area of the US (we have 200+ distribution utilities and all of their rules are different). And once approved, you are only approved for that very specific motor.
For a solar inverter because they all agreed to approve the UL listed ones. they rubber stamp the engineering fee. It is literally cheaper to use the solar inverter system. Which has the benefit of precisely matching the waveforms and shutting off power to the grid in the event the grid goes down.
10 Likes
Realistically, I don’t think any of this tinkering can be justified with economical reasons. However, earning 2€/kWh is an appealing scenario.
6 Likes
Is that what you get for solar for a feed in tariff? I know Germany originally was paying something insane like that.
4 Likes
That was only for one afternoon a week ago. But it has been like that before, and will be again as weather is cold and huge nuclear power plants will be out of operation for a month as scheduled…
9 Likes
Do you guys get any advance notice? If you can paid that much, that pays for a pieced together system in a day.
7 Likes