notes on
The
atomic weight of carbon is 12 atomic mass units,
while the
weight of
carbon
dioxide is 44,
because it
includes two
oxygen atoms that each weigh 16.
So, to
switch from one
to the
other, use the formula:
One ton of
carbon
equals
44/12 = 11/3 = 3.67 tons of CO2.
Dry
Matter Productivity (DMP) represents the overall growth rate or dry
biomass increase of the vegetation, expressed in kilograms of dry
matter per hectare per day (kgDM/ha/day). It is directly related to
ecosystem Net Primary Production (NPP), expressed in gC/m2/day.
Similarly, the Gross Dry Matter Productivity (GDMP) is directly related
to the Gross Primary Production (GPP).
The main difference between DMP/NPP and
GDMP/GPP is
the
inclusion of the autotrophic respiration of the vegetation.
To have the total value of NPP, i.e. including the roots of the trees,
we have to multiply by 2 because below ground
carbon biomass is, on average, equivalent to carbon allocated
aboveground.
3
tons of carbon fixes 11 tons of carbon dioxide.
KW Email Jan
24
If a heat
stove is the
next
level, then one household can make a couple of gallons of biochar a day
in the winter if they continually load up a 1 gallon paint can retort
with wood chunks and place it in the woodstove like a log.
Each paint
can will
yield
about 1/3 of a gallon of biochar, so 6 loads will give you 2 gallons.
It will
take 100 days
to make 200
gallons, which
is
about one cubic yard. which
is ~240 lbs.
If the household is making
biochar for use in the garden, composting, treeplanting, etc then they
will want a dedicated kiln like the Ring of Fire Kiln. One Ring of Fire can make 3
cubic yards
of biochar in 45 hours of burn time.
This is
about 700
pounds of
biochar.
We can
accurately
estimate
the carbon sequestration CO2 removal impact of each batch using a
protocol we are developing, but using our standard assumptions for
carbon content and bulk density of the biochar, we can confidently say
that multiplying the mass by 2x gives a conservative number for the
carbon sequestered.
So, 700
pounds of
biochar
times 2 = 1400 pounds of CO2 or .7 tons of CO2 removal.
In metric
tonnes (how
CO2 is
usually measured) that would be .6 metric tonnes of CO2.
If a
household makes 30
batches of biochar a year, they could sequester 19 metric tons of CO2
per year.
That is
equal to the
current
CO2 emissions of one highresource consuming American.
Here is a
number for
dry bulk
density of
biochar
made from
softwoods
is about 230 pounds per cubic yard.
Biochar
made from
hardwoods
is about 250 pounds per cubic yard.
To
estimate CO2 removal
for
any amount of biochar, measure and report the volume in cubic yards.
Multiply
by dry bulk
density
to get pounds.
Convert to
metric
tonnes and
multiply by 2 to get tonnes of CO2 removed from the atmosphere

https://biochar.groups.io/
20
t/ha would yield 4
to 5
tons of biochar with a potential to remove ~10 to 12.5 metric tons
CO2e.
20 ton per
hectare of
dry
biomass would yield 4  5 tons of biochar with a potential to remove 10
 12.5 metric tons of CO2e.
When you
subtract the
fossil
fuel inputs for harvesting and handling, power if used, transportation
of the biochar to use and the average temperature in the soil where it
is applied, the carbon dioxide removal potential would be between 2 
2.5 metric tonnes CO2e @ metric ton biochar.

At
4 metric tons @
hectare x
2.5 metric tons CO2e @ metric ton biochar
you would
sequester 10
metric
tons CO2e @ hectare @ year.
At that
rate you would
need
to harvest residues from 100 hectares @ 2000 dry metric tons wood @
1000 metric tons CO2e.
At one
metric ton of
biochar
per year and 2.5 metric ton CO2e per metric ton of biochar you would
need 400 homesteads to sequester 1000 metric ton CO2e.
Each
homestead would
sequester 2.5 mt of CO2e requiring 1 metric ton of biochar.
The EU
target is 2.5
mtCO2e @
capita,
equal
to one
metric ton
biochar per year.
In
developing
countries, the
average city
dweller emits 1.49
metric ton CO2e per year
while
rural inhabitants
emit
0.8 mt CO2e/year.
The 2017 Global Carbon
Emission target was 2.5  3.3 mt CO2e per person per year by 2030.
The
average global emission is about 3.4 mtCO2e/person per
year.
The
European average is
about
8.2mt CO2e/capita
which
would require
3.28 mt
biochar
from about
16 mt of
biomass.
The range
is 4  43
mtCO2e/capita.
EU
household carbon
footprints range from 4.6  54.9 mtCO2e @year.
According
to one study
US
households emit from 17.7  20.6 mt CO2 per person per year.
At 2.5 mt
CO2e/mt
biochar
they would have to produce 7.1  8.25 mt of biochar from about 35  42
mt of dry biomass residues per person per year.
Someone on
the list
reported
rural smallholders producing about 500 kg/biochar/.5mt per year
(Biochar Life?). The
stove production in
Vietnam that Joseph reported at 300g per meal would add up to
about 330 kg/.33 mt year which would be roughly equal to their carbon
footprint.
The pit
kilns, TLUDS
and top
lit piles that Kevin McLean has been working with might approach one mt
per year.
We need to
deal with
large
scale carbon dioxide removal (CDR). Biochar is clearly part of the
solution. Rural populations could probably remove as much CO2e as they
emit. However, urbanization has been the major trend in world
populations.
Tom

How
to
convert the total biomass to units of carbon per area?
Biomass is
typically
measured
in metric tons of dry mass of biomass per
area, usually per hectare.
To convert total biomass to units of carbon
per area, divide the total biomass by the mass fraction of carbon in
the biomass.
The mass fraction of carbon in biomass varies depending on
the type and source of the biomass,
but it is typically around 0.45 to
0.50.
For example, if the total biomass is 5 metric tons per hectare,
the amount of carbon per hectare would be 5 / 0.45 = 11 metric tons of
carbon per hectare.
NPP = Net
Primary
Production
50% of dry weight of biomass created is C (Carbon)
Heterotrophic Respiration. Around 20% of C is loss through
dead biomass decomposition.
NEP = Net Ecosystem Production.
1 ton of C corresponds to 3.667 tons of CO2.

To
convert above ground biomass and carbon to tonnes per hectare, you will
need to follow these steps:
 Convert
the biomass measurements to carbon using appropriate conversion
factors. Different vegetation types have different carbon contents, so
you need to consult relevant scientific literature or local studies to
determine the appropriate conversion factor for your area. For example,
a common conversion factor for forests is to assume that biomass is 50%
carbon.
 Multiply
the carbon content by the area of your land in hectares. If you have
measured the area, simply multiply the carbon content by the area. If
you have measured the area in a different unit (e.g., square meters),
convert it to hectares by dividing by 10,000.
 Express
the result in tonnes. The result of step 3 will be in terms of carbon
per hectare. To convert this to tonnes per hectare, divide the value by
10, as there are 10 tonnes of carbon in one tonne.
How
Applied Science Can Benefit Smallholder Farmers  with Dr. David Hughes
Biochar
Offset Permies.com
Life
Cycle Assessments of Biochar Systems
Biochar:
A Viable Option for Smallholders in the SubiHumid Tropics
