[permaculture] Fwd: Biochar
dhondt at eircom.net
Tue Nov 15 16:47:26 EST 2011
Charcoal has been a priced commodity for thousands of years and the main
reason for this was that charcoal is light. A cubic meter of timber would
weigh easily 3/4 metric ton but even a child could lift the half cubic meter
of charcoal resulting from charcoaling that cubic meter of timber. It was a
good bit easier to get 50 kilos of charcoal down the mountain than 2 ton of
fresh firewood. And of course another advantage is that charcoal burns a lot
hotter if you give it oxygen with a bellows than the original wood. (If you
don't give it enough oxygen it produces carbon monoxide that will kill you)
Charcoal was necessary for blacksmithing and smelting metals before cokes
The disadvantage is that most of the energy (and most of the nutrients)
captured in the wood went to waste and up in the air as CO2 (and SO2). And
that did not matter much in far away days. However, most of the bio-char
sites still use the same techniques of making charcoal as in the middle ages
and the result, the production of 20 times more CO and CO2 gas than is
retained in the charcoal remains the same too. As a means to sequester
carbon this is ridiculously wasteful and inefficient and damaging to the
Advanced pyrolisis on the other hand makes use primarily of the gasses
produced while charcoaling which is mainly CO and methane with some
hydrogen. It is well possible to drive petrol engines on this gas mixtures
and that was done extensively during WW2 in many places.
Unfortunately it is not quite that simple. I know a man not far from here
who drove a WW2 truck on wood gas in his youth in Holland and according to
him the only timber that would give the truck a range of more than a few
miles was very dry beech wood. Not even seasoned oak would do. (we have none
of the above trees here in any quantity)
These days one can buy (or make) very advanced woodgas makers that can be
used to drive turbines to produce electricity but the installation that I
would need to produce 4 KW (not enough for electric welding) would cost
around 40 thousand euros if we bought it and probably more than 20 thousand
if we made it ourselves. It is mainly but not only the price that has put me
off this. It takes about an hour to fire up and since we have mostly
softwood available that produces lots of tar it takes hours to clean after a
It also needs an electric supply for start up. This is not appropriate
technology for poor rural people even if it is admittedly quite efficient
since it uses primarily what was waste in earlier systems. But of course
many essential mineral nutrients still go up in smoke as is the case in
original charcoal making.
I would be very grateful to learn more of your planned wood gassifier for
the price of even one tank of propane is much higher here than your complete
installation. We ourselves at the moment use mostly very efficient wood
stoves that release luke warm air only up the chimney but of course we burn
the charcoal as well in this process. Meaning that we use much less wood
than we would if we tried to save the charcoal.
I do think that there are other low tech solutions to produce gas that are
more efficient and environmentally friendly such as methane fermenters. In
warm places they would be even more efficient and cheaper. I have seen
Chinese systems that get by with one steel drum dropped into a cylindrical
hole in clay and a length of flexible pipe straight to the gas cooker. If
you don't have an impermeable clay soil you would need some cement to coat
the hole. Gas pressure can be easily controlled by some stone put on top of
We built a big methane fermenter here in Ireland but unfortunately the speed
of fermentation depends on temperature. We measure just 7 C average in our
tank. The fermentation speed doubles with every ten degrees extra
temperature. We are working (much too slowly) to install a passive solar
heather into our tank.
In your previous mail you stated that the "science" of bio-char use was well
established. You know, I have had good quality charcoal at my disposal for
over 20 years and being a scientist myself I did a lot of experiments.
Sorry, but at best I found no effect at all even with charcoal that had
matured for over a year in a compost heap. Many of the bio-char sites think
it is necessary to mature the charcoal for the fresh stuff contains traces
of organic hydrocarbons that are most obviously toxic to soil life and
plants. Benzene and Xylene are found in fresh charcoal to name but a few.
Used out in the open garden I never found any (positive) effect and in
trials in pots with seedlings I found negative growth results and more so if
the concentration of charcoal was higher. I have yet to meet somebody who is
sold on the charcoal hype who has done a single convincing experiment
himself except for one single person who used charcoal in soil to remediate
severe pesticide toxicity. (and after that still decided it was safer to
grow vegetables in imported soil in plastic wading pools above the ground.)
I would also think that charcoal would help in binding heavy metals in soil
but that seems not to be a problem here.
To me if charcoal was really that good there would be no reason to call it
"living coal" for charcoal is completely inert and life less. It will still
be in soil unaltered in a thousand years. Real life means change.
> Thats absolutely not true. Biochar is about making heat from pyrolysis,
> heating biomas to get the biomas to off gas, burning in a non oxygen
> environment. The heated gasses can then be burned, and the heat from that
> be used for things that we need heat for, cooking, space heating, water
> heating, running a sterling engine, etc. The "bad" gases are burned off,
> and what is left behind is the carbon, which has a lot of surface area for
> your soil bacteria and fungi. Its like an apartment building for
> mocrorganisms, and greatly aids in fertility. The carbon applied to the
> soil is very stable, and will be effectively removed from the atmosphere
> for a long time.
> We are working on developing a home stove at low cost for families who
> burn wood for cooking here in southern Belize. This is an alternative for
> rural people who cannot afford the natural gas/propane/butane/fossil fuel
> that people in more developed countries use. We have a design that uses a
> 55 gallon drum and a welded old propane tank. Total cost? About USD75,
> less than the price of two full tanks of propane, and it gives heat for
> cooking, has fairly complete combustion, and leaves us with carbon to bury
> in the soil. This is not an industrial byproduct, or a way to make money.
> It is a way for small farmers to improve their soils while sequestering
> carbon (generated in natural gas/propane/butane/fossil fuel run stoves,
> for example), while getting the heat they need to do their cooking.
> Again, I suggest anyone considering the merits, or lack of, of biochar, to
> read Albert Bates book, "The Biochar Solution". That is one way to become
> an informed person on the subject.
> On Nov 14, 2011, at 11:01 PM, Lawrence F. London, Jr. wrote:
>> On 11/14/2011 5:31 PM, John D'hondt wrote:
>>> They don't yet know how it works? But they are already telling everybody
>>> to make it? Burning the planet to cool it?
>>> If it were not for the very name which comes under the heading of
>>> "new-speak" in Brave New World more people might wonder if it worked at
>>> as do I. Bio means life and char means coal and freedom is slavery and
>>> is peace.
>> Its all about using an industrial (probably wasteful and polluting
>> processes) byproduct to create another product to market for high dollar.
>> It does not make any sense to char biomass to make charcoal that then
>> must be pulverized and field spread (often using fossil fuel) when all
>> that needs to be done is to allow weeds to control weeds, crimp or roll
>> them to make a semi living mulch that controls weeds, adds seeds and
>> organic matter to soil to increase OM and eventually humus while
>> significantly building soil quality and productive capacity.
>> Thumbs up for notill agriculture (and minimum till).
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> Christopher Nesbitt
> Maya Mountain Research Farm
> San Pedro Columbia, Toledo
> PO 153 Punta Gorda Town, Toledo
> Central America
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