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Before
summarizing some of the findings of this report, its readers are
cautioned that these are projections based on a series of assumptions.
In addition, the world is changing at an ever increasing rate. As a
result it is often difficult to predict what will happen next year, let
alone in 2030, as is done in this document. However, having said that,
the report is the best these scientists could do at this time, and what
they predict is at least a possibility.
The
report indicates that nearly 1 billion dry tons of biomass can be
produced from agricultural lands each year by 2030 without negatively
impacting food, feed and export capacity. This estimate includes 428
million tons of annual crop residues, 377 million tons of perennial
crops like switchgrass, 87 million tons of grains used for biofuels
(mainly corn for ethanol and soybeans for biodiesel). And 106 million
tons of animal manures, process residues, and other materials. Important
assumptions that were made for agricultural lands included the
following:
-
Based
on past increases, yields of corn and small grains increase by 50%
-
The
residue-to-grain ratio of soybeans increases from 1.5:1 to 2:1
-
75%
of crop residues are used
-
All
cropland is managed with no-till methods
-
55
million acres of cropland, pasture land and CRP acres were used for
perennials like switchgrass
-
All
manure except that needed for fertilizer is used for biofuel
production
-
All
other available residues are used
Of
some concern here is that crop residues provide about half of the total
biomass expected from agriculture, and it is assumed that 75% will be
removed. This seems to be a rather high removal rate if preservation of
soil quality is expected. The argument is that no-till procedures should
allow more removal without soil degradation than conventional tillage.
However, only long term experiments can verify this assumption, and
there are no such experiments because no-till operations have only been
widely applied relatively recently.
On
the forestry front, it is expected that 368 million dry tons of biomass
can be produced annually. This includes 52 million tons of fuel wood
harvested from forests, 145 million tons of residue from wood processing
mills and pulp and paper mills, 47 million tons of urban wood residues,
64 million tons from logging and site clearing operations, and 60
million tons from thinning to reduce fire hazards. For this forestry
resource estimate the following assumptions were made:
-
All
forest land currently not accessible by roads were excluded
-
No
environmentally sensitive land was included
-
Recoverable
biomass was divided into two categories – conventional forest
products (not included in the estimates) and biomass for bioenergy
and biobased products
So,
in summary, the report predicts that it would be possible to sustainably
produce a total of 1.37 billion dry tons of biomass per year (or 37%
more than the original vision) by 2030 from crop and forest resources.
This would allow us to produce more than 30% of our transportation
fuels. The report draws the following conclusions:
"The
biomass resource potential identified in this report can be produced
with relatively modest changes in land use, and agricultural and
forestry practices. This potential, however, should not be thought of as
an upper limit. It is just one scenario based on a set of reasonable
assumptions. Scientists in the Departments of Energy and Agriculture
will explore more advanced scenarios that could further increase the
amount of bio-mass available for bioenergy and biobased products." |
