[Terrapreta] this is agood article I have not included comments the rest is at:

[Michael Bailes]

The rest is at http://www.worldchanging.com/archives/007427.html

A Carbon-Negative Fuel

Jeremy Faludi <http://www.worldchanging.com/jeremy_bio.html>
October 16, 2007 8:07 AM

[image: Article Photo]

"Impossible!" you say. "Even wind and solar have carbon emissions from their
manufacturing, and biofuels are carbon neutral at best. How can a fuel be
carbon negative?" But listen to people working on
gasification<http://en.wikipedia.org/wiki/Gasification>and terra
preta <http://en.wikipedia.org/wiki/Terra_preta>, and you'll have something
new to think about.

We've mentioned terra
preta<http://www.worldchanging.com/archives//004815.html>before: it's
a human-made soil or fertilizer. "Three times richer in
nitrogen and phosphorous, and twenty times the carbon of normal soils, terra
preta is the legacy of ancient Amazonians who predate Western civilization."
Although we don't know how it was made back then, we do know how to make it
now: burn biomass (preferably agricultural waste) in a special way that
pyrolisizes <http://en.wikipedia.org/wiki/Pyrolysis> it, breaking down long
hydrocarbon chains like cellulose into shorter, simpler molecules. These
simpler molecules are more easily broken down by microbes and plants as
food, and bond more easily with key nutrients like nitrogen and phosphorus.
This is what makes terra preta such good fertilizer. Because terra preta
locks so much carbon in the soil, it's also a form of carbon sequestration
that doesn't involve bizarre heroics like pumping CO2 down old mine shafts.
What's more, it may reduce other greenhouse gases as well as water
pollution: according to Biopact <http://biopact.com/>, a network that
promotes biofuels and biomass energy,

*Char-amended soils have shown 50 - 80 percent reductions in nitrous oxide
emissions and reduced runoff of phosphorus into surface waters and leaching
of nitrogen into groundwater. As a soil amendment, biochar significantly
increases the efficiency of and reduces the need for traditional chemical
fertilizers, while greatly enhancing crop yields. Experiments have shown
yields for some crops can be doubled and even tripled.*

As it happens, the process of burning/pyrolisizing agricultural char is also
a way to produce energy. MIT Professor Amy
Smith<http://web.mit.edu/invent/a-winners/a-smith.html>,
a recipient of the prestigious MacArthur "genius
award,"<http://www.macfound.org/site/c.lkLXJ8MQKrH/b.959463/k.9D7D/Fellows_Program.htm>gave
a TED
Conference talk <http://www.ted.com/index.php/talks/view/id/2> in 2006 on
using agricultural char as fuel in developing countries. It works because
the chemical reactions that break down the long hydrocarbon chains also give
off hydrogen gas, methane, and various other burnable fuel gases. (As well
as tars and non-useful gases like CO2.) This is gasification. The fuel gas
can be burned for heat, or if it's pretty clean (that is, if the tar levels
are low), it can be used to power an engine.

I was first introduced to gasification by Jim
Mason<http://www.whatiamupto.com/>at Foo
Camp <http://en.wikipedia.org/wiki/Foo_Camp>, and helped a bit with his
Burning Man project The Mechabolic <http://www.mechabolic.org/>. It's an art
project designed to use gasification for motive power, electrical power, and
gas-powered lights and heat, all at the same time. The Mechabolic is
intended to run off of coffee grounds, or whatever ground-up dried-out
biomass can be fed to it, with its own "mouth" parts to chop up and
pulverize incoming material well enough to be fed into its gasifier tank.
Jim points out that gasification is not new -- in fact, according to Professor
Tom Jeffries <http://www2.biotech.wisc.edu/jeffries/faq/literature.html> at
the University of Wisconsin, "Over a million wood gasifiers were used to
power cars and trucks during World War II," when Europeans often lacked
access to oil.

There are many kinds of
gasifiers<http://www.fao.org/docrep/t0512e/T0512e0a.htm>,
each with advantages and disadvantages for different conditions and input
materials. Babcock & Wilson Vølund have a helpful
diagram<http://www.volund.dk/layout/set/print/content/view/full/714>(see
below) with explanatory text that shows one kind in detail. The
locations and sizes of the different zones will be different for other
designs, but the sorts of chemistry described occur in all gasifiers.

[image: gasifier_zones.jpg]

Not all gasification is green. The coal industry routinely uses gasification
all around the world<http://www.peabodyenergy.com/Education/Gasification.asp>to
create
syngas <http://en.wikipedia.org/wiki/Syngas> (synthetic gas) as a petroleum
substitute of chemical feedstock. However, gasification plus terra preta has
potential to be revolutionary.


I can't promise that using gasification for energy and using the resulting
char as terra preta fertilizer will be a carbon negative fuel, because I
haven't seen a credible lifecycle analysis of it. (If anyone has, please
post it to the comments.) But it's quite plausible. Consider that it takes a
certain amount of CO2 to grow a crop, such as corn. You harvest the crop and
sell the food part, which leaves you with all the agricultural waste.
Instead of burning it in the open air, or landfilling it (which is what's
done today -- basically topsoil mining), you gasify it. You then burn the
fuel gas you get from gasification, putting some fraction of that CO2 into
the air; the agri-char (terra preta) that you're left with contains the rest
of the embodied CO2 which the crops sucked up while growing. There's more
carbon here than there was in the fuel gas. You spread the terra preta on
the fields as fertilizer to grow more crops, and repeat the cycle -- and
with each repeat, you pull more carbon back into the soil than you burn,
resulting in a carbon negative fuel as well as crops fertilized with fewer
petrochemicals. It's a double win.


*Energy Policy and Farm Policy*

Gasification and terra preta as a means of sequestering carbon is far
cheaper than injecting CO2 into mine shafts, but it's still not cheap.
Biopact<http://biopact.com/2007/10/towards-carbon-negative-bioenergy-us.html>calculated
that "under a basic scenario sequestering biochar from biofuels
produced by pyrolysis would be competitive when carbon prices reach US$37
(carbon currently fetches €21.55 on the European market, that is $30.5, and
prices are expected to increase strongly in the near future)."

However, "[T]he great advantage of biochar is the fact that the technique
can be applied world-wide on agricultual soils, and even by rural
communities in the developing world because it is relatively low tech." In
fact, the guts of Jim Mason's Mechabolic was mostly built with scrap steel
tanks and whatever miscellaneous piping was handy, with nothing but a couple
welders and some power tools -- nothing a well-equipped farm mechanic
wouldn't have.

One of the 2007 Ashden Awards
<http://www.ashdenawards.org/finalists_2007>went to a company in India
making gasification / char systems in Kerala:

*BIOTECH has succeeded in tackling the problem of the dumping of food waste
in the streets of Kerala through the installation of biogas plants that use
the food waste to produce gas for cooking and, in some cases, electricity
for lighting; the residue serves as a fertiliser. To date BIOTECH has built
and installed an impressive 12,000 domestic plants (160 of which also use
human waste from latrines to avoid contamination of ground water), 220
institutional plants and 17 municipal plants that use waste from markets to
power generators. The disposal of food waste and the production of clean
energy are not the only benefits of BIOTECH's scheme. The plants also
replace the equivalent of about 3.7 tonnes/day of LPG and diesel which in
turn results in the saving of about 3,700 tonnes/year of CO2, with further
savings from the reduction in methane production as a result of the
uncontrolled decomposition of waste, and from the transport of LPG.*

While still under the radar of most policymakers, gasification and terra
preta are starting to appear on the scene. In the US this year, Senator Ken
Salazar (D-CO) is promoting legislation that would give subsidies of up to
$10,000 for farmers who set up gasifiers and use the terra preta on their
fields, and $100 million in related research grants. Biopact has the full
text of the bill
online<http://biopact.com/2007/10/towards-carbon-negative-bioenergy-us.html>,
and Biochar International<http://www.biochar-international.org/newinformationevents/newlegislation.html>has
a summary of the bill.
*Image: The Mechabolic at Burning Man. Credit: Michael P Byrne*

-- 
Michael the Archangel

"You can fix all the world's problems in a garden. . . .
Most people don't know that"
FROM
http://www.blog.thesietch.org/wp-content/permaculture.swf
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