[Terrapreta] carbon and compost

[Duane Pendergast]

Tom,

You estimate production costs of char at about $125 to $200 per ton. I guess
that translates to about $35 to $55 per ton of CO2 captured if the char is
taken to be all carbon. It's good to see you are focusing on the value of
benefits if that char is placed in the soil. 

It is interesting to compare your production costs for char with some costs
for CO2 emissions currently proposed for carbon management in Canada.

The province of Alberta has recently decreed that large emitters must
decrease their output of CO2, or alternatively pay $15/tonne of excess
carbon dioxide emitted beyond a baseline level into a climate change and
emissions management fund.

http://www3.gov.ab.ca/env/climate/

Our federal government has talked in terms of $10 to $50 per tonne of carbon
dioxide equivalent for several years now as noted in the undated plan below.
I believe it is from 2002 per my memory and the ISBN number.

http://www.climatechangeconnection.org/pdfs_ccc/full_version.pdf 

A recent federal government study linked below indicated a tax of $195/tonne
of CO2 emissions plus purchase of a limited number of credits at $25 tonne
of Co2 would be needed to shock Canada's economy into meeting the Kyoto
commitment. That analysis is based on about ten years of detailed study of
Kyoto implementation. I find it quite credible.

http://www.ec.gc.ca/doc/media/m_123/c6_eng.html

Canada's Green Party proposes a simple tax of $50/tonne of carbon dioxide
equivalent on all emissions. My household emissions are about 30 tonnes
annually so this implies additional costs to me of about $1500/ annum unless
I can find some way to reform. A typical Canadian car would see an annual
fuel cost increase of about $250.00. This would still not amount to a very
substantial deterrent. $195 per tonne would likely make some sit up and take
some notice. Aside from the Alberta legislation, it is hard to take the rest
of it very seriously as the climate debate and proposed actions in Canada
include a large component of political posturing. I do expect the Alberta
action will actually proceed.

Your estimates of the production cost of char ($35 to $55) in terms of CO2
absorbed are well below estimates of the price to be placed on carbon
dioxide emissions as a means of controlling them. I find that quite
encouraging. There is a way forward should the world find it actually needs
and wants to control carbon emissions.

It will be really interesting to see results coming forth on the agronomic
value of char as you have outlined the case. I think that is fundamentally
very important - regardless of the outcome of climate change considerations
and greenhouse gas management - in terms of the potential for growing the
planet's productivity.


Duane






 

-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Tom Miles
Sent: July 13, 2007 11:10 PM
To: 'Robert Klein'; 'terra preta'
Subject: Re: [Terrapreta] carbon and compost

Bob,

In our valley we harvest and process 740,000 tons of straw each year from
our grass seed crop (530,000 acres). We recover 2-3 tons per acre from the
perennial crop and leave the stubble. We used to burn all of the straw and
the stubble. Then we developed burners to burn the stubble-only (1.5 t/a)
and removed the straw. We developed markets for the straw. Now we just leave
the stubble. I can tell you from more than 32 years experience that a
pyrolysis system that meets our environmental and agro-industrial
regulations will cost about $40 to harvest and process a ton of straw, or
about $200/ton of char. ($20/ton harvest and field side/store; $20/ton to
process; 20% yield of char).            

During the last five days on my commute to work I have seen three small
houses demolished, ground up, and hauled off. Each house was probably about
120 m2 (1200 ft2) and sat on 1200m2 (12,000 ft2 ~ 0.3 acres). When the
landscaping was scraped off and everything was put through the tub grinder
the wood waste filled about three trucks of about 15 tons each. So the haul
was about 15 tons per house. I could tell by the trucks that the wood
probably was sold as fuel to one of three pulp mill boilers I work on in the
area. The pulp mill probably paid about $20/ton for the delivered fuel.
Except for permits and inspections (I saw only a water agency truck) the
public agencies were probably not involved.

Our agencies in Oregon would not permit the agricultural charcoaler that you
describe. An agricultural charcoaler in our valley would have to comply with
all of the industrial and emissions standards that are anticipated in the
ABRI pilot, and more, so I will use it as an example. The three 15 ton
truckloads could have been processed in Peter Fransham's 50 tpd Advanced
Biorefinery in a day. At 20% charcoal yield each truck (or house) would have
produced about 3 tons of char, enough to offset my personal production of
CO2 in a year (See http://terrapreta.bioenergylists.org/carbondioxide ) at a
net cost of about $125/ton char. (See

001261.html )   

If I inject the char in rows at a concentration of 6 tonne/ha (2.46 t/a) in
100 mm (3.9 in) bands like the oil mallee charcoal, which if broadcast would
equal 1 tonne/ha (.42 t/a), (See
http://terrapreta.bioenergylists.org/oilmalleeiai07 ) then I could treat
7.12 acres of crop with 3 tons (2.73 tonne) of charcoal from one house or
one 15 ton truckload of urban wood.

What agronomic benefit, and hence what economic value ($/acre), would the
char have over a 5 year period? Would it offset the $20/ton delivered fuel
cost or the $125/ton (.42 t/a x $125/t = $53/a; $10.6/a/yr at 5 years) total
char processing cost? Or, if char from straw, $200/ton, $84/a or 17/a/yr?
These are values that we have yet to determine for most applications in our
temperate soils. 

Tom