Is charcoal really less efficient? Im beginning to wonder

Naa,… this isn’t claiming one or the other…
Just creating this topic to put answers regarding the subject on one place…

As my daily work involves"energy" and biomass 7/24/365… and i do love experimenting, i have one answer, not only the obvious “it depends” but also “follow the (your) road from fuelprep to actual shaftpower used ( or electric generated )”

It boils down to simple math’s and simple physics… ; “where does the heat go ?” and “where should the heat be ?”

Some might remember one of my builds that includes the plastic “gasifier”; well that is still on and even getting scaled up, including extracting useable diesel, gasoline and heavy fuel…

It all depends on how you manage your heat and what purpose you can give it…

Exhaust heat from IC engine ? ( what heat is needed to pyrolyse plastic ? oops, giving out to much info…)

Catalystic reforming ? it depends
Charcoaling and preheating house ?
Boiling water ?
Desalinating ?
Drying processes ?
Using heat from charcoaling for distilling organic residue’s ?
Wanting to make liquid smoke for seasoning meat ?
Cooking mapple syrup ? during charcoaling making ?
Using the heat for boiling steam and running a steam waterpump ?
Steam turbine generator ?

So many things in favor for the one or the other… it all depends…
Use your imagination…
Use wood for your energy needs and do it wisely…


I just shovel it out of the outdoor wood boiler home heater. Then filter it over a modified patio umbrella table. Then hand grind it.


Snap ! 90% of my daily running charcoal is all made indoors from my wood heating fire , the other 10% is everything that falls onto the ground in my garden leafs and bark & twigs and trust me we get a lotta lotta bark ( mountain ash gum tree’s ) that’s all burnt in a cone out side in the garden and then shoveled into 55 gall drums for when needed during summer cloudy days mixed with what ever hard wood chunked charcoal from the home fire i have left


What’s the most efficient charcoal retort from which you could extract the waste heat, and how do it safely? I’m thinking that if there’s a good user-friendly design out there from which I could siphon the heat to heat my shop or heat water, I just might give this a try. Problem being, I haven’t found such a design yet. Newbie here.


Hi Bryan , and welcome back .
There are a few ways to make charcoal and use the heat for keeping your shop warm and there are also ways to convert them to heat water for use in a hydronic heating system with radiators , if you look on here for Gary Gillmore’s keystone stove or Google it , that makes charcoal in batches you load a small container loaded with wood and its a TLUD fire and so as it burns down to the bottom all on top is charcoal , you simply take out that container once its all down to charcoal and load another container in and carry on , in the mean time you empty that container out into a air tight drum to cool off and on and on you go .
Another really efficient system is one found on youtube , its called the Hookway retort , its almost like a rocket stove with insulation all around the container you light a small fire in the bottom and after a short while it will start gassing off and it uses its own gasses to carry on converting the wood to charcoal , i guess it could be used indoors but its not as safe as the keystone stove in my opinion , but you can make a much larger batch once a day in it .



I like this concept. I believe it could be converted to a heating device.


Hi Garry, yes , that is a great system…
Now picture this next set on top of that… ( spoiler: doing this already… )


That’s a great video Koen. That’s by far the best solution i’ve seen yet for certain waste plastics. Thanks for bringing that forward. Hopefully it is widely employed.


Thanks Dave! I had seen the Hookway Retort before, looks very efficient, but like you noted I wasn’t too sure on how safe it’d be indoors, nor of an easy way to drain off the heat without reducing the efficiency. I’ll dig some more into Gary’s Keystone Stove, found a video on it but not yet clear on the specifics of how it’s built, but looks promising.

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Thanks Garry, looks cool, especially that auger, not sure though how to turn it into an indoor heater.


What Im interested in seeing is taking the bulk weight of your fuel media before processing for both charcoal production and chipped fuel production. Then process the fuels and calculating all fuels energy input. Fuel, energy used to prep the fuel for chipper or retort and then fuel energy used to process, running the chipper or the retort. Then sort through the chipped fuel and also process the charcoal and then finally weighing the usable product calculating your net energy potential.

Charcoal product at first glance seems like such a waste. But all ive seen done is burning bulk fuel media in a retort and then some very simple low energy consumption systems for grinding up the charcoal into a usable fuel.

Chipping fuel also consumes quite a bit of energy and is much more labor intensive plus loss of yield.

With a small chipper you seriously would be lucky to produce 40 lbs of usable fuel pr hour and this is not including drying the fuel.

I bet if a very thorough investigation was done charcoal would come out ahead. Free energy sources still need to count as energy in. For instance fuel drying in the sun will not always be an option, here in the northern states frozen fuel will not dry in the clouds.


Yeah, that is an interesting idea, and while I have not done a thorough study on the topic, I have crunched some numbers in the past.

When cutting chunks for Jakob, I used my battery operated chainsaw to cut the chunks. Each battery pack takes about 200wh to charge, and was able to cut 100lbs of chunks (~2" long). If you want it at 20% moisture, figure its going to be about 80lbs of fuel.

Now if i was making charcoal I could probably get away with a fraction of the cuts (20" logs). So the same 200wh would cut like 1000lbs of green wood. At about 40% moisture, I would have 600lbs of dry weight, and I found that charcoal productions using a retort or open kiln yields about 25% by dry weight. So I am down to 150lbs of charcoal. The grinding can be done with a fractional hp motor, so you are not really using up much of your fuel.

At the end, using plenty of hand labor for both processes, I figure I could get 80lbs of chunks, or 150lbs of charcoal with a similar amount of processing energy. If drying the chunks was needed, that would further hurt your yield, as charcoal can (in theory, i have never done it) be made from green wood.

Anyone with a rebak or other mechanical chunker ever tried to compute the power drawn to process a certain quantity of chunks? I suspect a chainsaw is not very efficient - but it might edge out a chipper.


Fantastic, thats awesome!! Then add a little steam reformer and you are putting back some of your losses to boot!! I was absolutely amazed at last years show when Dan pulled the steam away from his unit!


Those are good real world figures.

2 proposals for comparison.

#1, rebak chunking of sapling wood

#2, bandsawmill cutting of log wood into strips, and then chunking in a crosscut saw.

I suspect both will render a high efficiency.

I don’t consider drying as an energy expense, our weather fluctuations take care of that in a season.


Thats fine, you can take that out later as this is dependent the user circumstances. However to do this right we want to know the full energy in and out not just partial data. If you are off grid and run on wood gas full time, you could not dry enough fuel to keep up air drying. A mountain of chips only the surface will dry and rest will rot and compost. Then if you are not available to cover it every time it rains. You start all over again. Ive been there. :slight_smile: Id go and get a couple yards of chips and put out dry and then it would rain then its even harder to dry them. This is especially hardwoods cedar dries fairly rapidly.

But yeah Id like to see all methods possible. Your labor also needs to be factored. I like the idea of lighting a retort and walking away verses spending hours feeding a small chipper. The con of the other methods is the equipment is less common, more expensive or you build yourself.

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This is substantially important. Wildly inefficient processes could be very acceptable and even enthusiastically embraced in some scenarios if the personal labor input is minimal and the overall outcomes largely the same.


In the most KIS way to describe it…:
1: You have a certain pile of wood, same size and same proportions as for wood gasifier and or charcoal gasifier.
2: You have a gasifier to build/use to obtain a certain amount of work to do.
The amount of work to do ( job to perform) is equal for each gasifier.

Now, homework time, describe in detail anything between 1 and 2…

Edit: if you want to use waste heat for heating house or buildings, same goes for both.
But if you just want to chop wood for using it in a normal gasifier for driving… its a bit different i guess

IMHO, you can use the waste energy from the charcoaling process for many other things then just heating a house.
If you use a retort system, you can use the gas, escaping from the retort, to run a generator and cut up charcoal…
If you adjust your WK gasifier to have more char output, then you have charcoal for a gasifier also…
So many challenges… so many fun things one can think of…

The Nike way: just DO IT


Yeah I think reclaim should be a second portion of the calculations. Like the wood drying issue, Engine exhaust is quite effective for fuel drying and a reclaim.

Yup your labor is a source of energy and energy is a source of labor. Somewhere along the line you paid for the energy. If you used gasoline to power your equipment as an energy input. You paid for the fuel somehow. If you use wood for the retort heat process, you cut that fuel up for this process. Your labor feeding the equipment is not free, your adding labor, your labor is worth something.

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Does it really burn in a diesel without mods? And what is the yield rate?


should build angle disk chipper with water cooled engine running on wood gas using three phase generator on idler pulley . I have air cooled gasoline 6" capacity . Lot of waste , undersized chips and over size chips . I always need fill for holes in land . painted black concrete pad dries chips in day ,
very few days with sun , Canadian fires are producing nuclear winter or proving the concept .
I get charcoal fines , I need to remove charcoal fines to operate unit . I have tried burning then to grey ash , it did not work .
I have boiled down wood vinegar to white powder , did not save it .
I do appreciate your work Matt .
I wanted to send you tortified wood pellets for you to experiment with "arbaflame " sold these to Ontario power generation , thunder bay station. I think they are still selling the tortified wood pellets I just do not think they still have the tortified wood pellets to sell .
Other company produced tortified wood briquettes and do not have any but claims to have agreements to sell them .
Other company claims chemical process to make tortified wood pellets and I want nothing to do with them .
If I can get you some of the tortified wood pellets I would pay .
Henry Buehler