[Terrapreta] biochar for agriculture or energy?

[lou gold]

Does anyone know of more recent assessments???


Here is what Lehmann said in Feb, 2006

*Whether global carbon trading mechanisms are a sufficient incentive for
potential agricultural bio-char users to compete economically with those who
use bio-char as fuel remains unknown, said Cornell's Lehmann. 'If we can
plug in other environmental benefits such as reduced offsite pollution with
nitrogen and phosphorous, or reduced fertiliser use, we can see immediate
economic kickback that will make it more attractive than burning the
bio-char either in home cooking or in a power plant,' he said.
http://www.rsc.org/chemistryworld/News/2006/February/20020601.asp
*
*and the following

* Lehmann, J., Gaunt, J., and Rondon, M., 2006, Bio-char sequestration in
terrestrial ecosystems – a review.
*
*











Biochar:  A Soil Amendment that Combats Global Warming and Improves
Agricultural Sustainability and Environmental Impacts

Introduction to Biochar

Biochar and bioenergy co-production from urban, agricultural and forestry *
biomass* can help combat *global climate change* by displacing fossil fuel
use, by sequestering carbon in stable soil carbon pools, and by dramatically
reducing emissions of nitrous oxides, a more potent greenhouse gas than
carbon dioxide.1<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote1>
,2<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote2>
As a soil amendment, biochar helps to improve the Earth's soil resource by
increasing crop yields and productivity, by reducing soil acidity, and by
reducing the need for some chemical and fertilizer
inputs.3<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote3>
,4<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote4>
Water quality is improved by the use of biochar as a soil amendment, because
biochar aids in soil retention of nutrients and agrochemicals for plant and
crop utilization,5<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote5>
,6<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote6>reducing
leaching and run-off to ground and surface waters.


Biochar production and utilization systems differ from most biomass energy
systems because the technology is *carbon-negative*:  it removes net carbon
dioxide from the atmosphere and stores it in stable soil carbon
"sinks".7<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote7>
Other biomass energy systems are *at best* carbon-neutral, resulting in no
net changes to atmospheric carbon dioxide.

Biochar Production

*Bioenergy* and * biochar* can be co-produced from thermal treatment of
biomass feedstocks.  The thermal conversion of biomass, under the complete
or partial exclusion of oxygen, results in the production of biochar and
bioenergy or other bioproducts.  Biochar production processes can utilize
most urban, agricultural or forestry biomass residues, including wood chips,
corn stover, rice or peanut hulls, tree bark, paper mill sludge, animal
manure, and recycled organics, for instance.

Under controlled production conditions, the carbon in the biomass feedstock
is captured in the biochar and the bioenergy co-products.  Theoretically,
the *biochar* co-product will retain up to 50% of the feedstock carbon in a
porous charcoal structure; and the remaining 50% of the feedstock carbon
will be captured as *bioenergy.* While it is technically infeasible to
capture 100% of the biomass carbon, since energy is invariably used and lost
in the production process, the optimal biochar production process can
capture roughly half the biomass carbon in biochar and half as bioenergy.

*Biochar* can be produced by *pyrolysis* or *gasification * systems.
*Pyrolysis
* systems produce biochar largely in the absence of oxygen and most often
with an external heat source.  There are two types of pyrolysis systems in
use today:  *fast pyrolysis* and *slow pyrolysis* systems.
*Gasification *systems produce smaller quantities of biochar in a
directly-heated reaction
vessel with air introduced.  Biochar production is optimized in the absence
of oxygen.

Gasification and pyrolysis production systems can be developed as mobile or
stationary units.  Small scale gasification and pyrolysis systems that can
be used on farm or by small industries are commercially available with
biomass inputs of 50 kg/hr to 1,000 kg/hr. The bioenergy produced from these
systems, which can be in the form of a synthetic gas, or *syngas*, or *
bio-oils*, can be used to produce heat, power or combined heat and power. At
the local or regional level, pyrolysis and gasification units can be
operated by co-operatives or larger industries, and can process up to 4,000
kg of biomass per hour.

Biochar

*Biochar * is a fine-grained, porous charcoal substance that, when used as a
soil amendment in combination with sustainable production of the biomass
feedstock, effectively removes net carbon dioxide from the
atmosphere.8<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote8>
In the soil, biochar provides a habitat for soil organisms, but is not
itself consumed by them to a great extent, and most of the applied biochar
can remain in the soil for several hundreds to thousands of
years9<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote9>
,10<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote10>(see
also
*Terra Preta soils*). The biochar does not in the long-term disturb the
carbon-nitrogen balance, but holds and makes water and nutrients available
to plants.  When used as a soil amendment along with organic and inorganic
fertilizers, biochar significantly improves soil tilth, productivity, and
nutrient retention and availability to
plants.11<http://www.biochar-international.org/images/Biochar_White_Paper_-_FINAL_10-9-07_w-o_links.doc#footnote11>


Bioenergy

The *bioenergy* produced during biochar production may be in the form of
thermal energy, a synthesis gas, aka *syngas, * or a* bio-oil*.  The syngas
or bio-oil can be used to heat the pyrolysis unit for continued production,
and surplus syngas or bio-oil can be used to provide additional energy for
on-site uses, such as heat and electricity.  *Syngas* is rich in hydrogen,
methane and carbon monoxide and in addition to its use for heat or power, it
can be converted to *liquid fuels * or industrial *chemicals. * The bio-oils
can also be used for on-site power and heat generation, or converted to *liquid
fuels* or industrial *chemicals*.

Economics of Biochar Systems

The co-production of biochar from a portion of the biomass feedstock reduces
the total amount of bioenergy that is produced by the technology, but even
at today's energy and fertilizer prices the net gain in soil productivity is
worth more than the value of the energy that would otherwise have been
derived from the biomass feedstock.  As the cost of carbon emissions rises
and the value of CO2 extraction from the atmosphere is also considered, the
balance becomes overwhelmingly attractive in favor of biochar co-production.


Rural and Developing Country Applications of Biochar Systems

Biochar systems can reverse soil degradation and create sustainable food and
fuel production in areas with severely depleted soils, scarce organic
resources, and inadequate water and chemical fertilizer supplies.  Low-cost,
small-scale biochar production units can produce biochar to build garden,
agricultural, and forest productivity, and bioenergy for eating, cooking,
drying and grinding grain, producing electricity and thermal energy, for
instance.

1 Yanai et al., 2007, Effects of charcoal addition on N2O emissions from
soil resulting from rewetting air-dried soil in short-term laboratory
experiments, *Soil Science and Plant Nutrition*, 53:181-188.

2 Rondon, M., Ramirez, J.A., and Lehmann, J.:  2005, Charcoal additions
reduce net emissions of greenhouse gases to the atmosphere, in * Proceedings
of the 3**rd** USDA Symposium on Greenhouse Gases and Carbon Sequestration*,
Baltimore, USA, March 21-24, 2005, p. 208.

3 Glaser, B., Lehmann, J. and Zech, W., 2002, Ameliorating physical and
chemical properties of highly weathered soils in the tropics with charcoal
--- a review, *Biology and Fertility of Soils*, 35: 219-230.

4 Lehmann, J. and Rondon, M., 2006, Biochar soil management on highly
weathered soils in the humid tropics.  In Uphoff N (ed.), * Biological
Approaches to Sustainable Soil Systems*, CRC Press, Boca Raton, FL, pp.
517-530.

5 Lehmann, J., et al., 2003, Nutrient availability and leaching in an
archaeological Anthrosol and a Ferralsol of the Central Amazon basin:
fertilizer, manure and charcoal amendments, *Plant and Soil*, 249: 343-357.

6 Steiner, C., et al., Long term effects of manure, charcoal and mineral
fertilization on crop production and fertility on a highly weathered Central
Amazonian upland soil, *Plant and Soil*, 291: 275-290.

7 Lehmann, J., Gaunt, J., and Rondon, M., 2006, Bio-char sequestration in
terrestrial ecosystems – a review.  Mitigation and Adaptation Strategies for
Global Change, 11:403-427.

8 Ibid.

9 Pessenda, L.C.R., Gouveia, S.E.M., and Aravena, R., 2001, Radiocarbon
dating of total soil organic matter and humin fraction and its comparison
with 14C ages of fossil charcoal, *Radiocarbon*, 43: 595-601.

10 Schmidt, M.W.I., Skjemstad, J.O., and Jager, C., 2002, Carbon isotope
geochemistry and nanomorphology of soil black carbon:  Black chernozemic
soils in central Europe originate from ancient biomass burning. * Global
Biogeochemical Cycles*, 16: 1123.

11 Glaser, B., Lehmann, J. and Zech, W., 2002, Ameliorating physical and
chemical properties of highly weathered soils in the tropics with charcoal
--- a review, *Biology and Fertility of Soils*, 35: 219-230.

*

*
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