Abstract
An ever-increasing demand for liquid fuels, amidst concerns of
anthropogenic impacts on the environment and fossil fuels availability,
has spurred a strong interest in the development of agriculturally-based
renewable energy sources. However, increasing demand for food as well as
direct and indirect effects on land use, have raised concerns about
reliance on grain-based ethanol and shifted research towards the
direction of cellulosic feedstocks. In order to understand the future
possibility for using agricultural systems for bio-fuel production, we
present here a full greenhouse gas (GHG) balance of six potential
sources of cellulosic feedstocks production. From 1991 to 2008, we
measured GHGs sinks and sources in cropped and nearby unmanaged
ecosystems in SW Michigan. The measurements included soil fluxes of GHGs
(N2O and CH4), soil organic carbon concentration change, agronomic
practices data, and biomass yields. We analyzed two types of intensively
managed annual cropping systems under corn-soybean-wheat rotation
(conventional tillage and no till), two perennial systems (alfalfa and
poplar plantation), and one successional system. The use of agricultural
residues for biofuel feedstock from conventionally-tilled crops had the
lowest climate stabilization potential (-9 ±13 gCO2e m-2 y-1). In
contrast, biomass collected from a successional system fertilized with N
at123 kg ha-1y-1 showed the highest climate stabilization potential
(-749 ±30 gCO2e m-2 y-1). We used our results to parameterize the
EPIC model, which, together with GIS analysis was used to scale up the
biomass productivity of the best environmentally performing systems to
the marginal lands of the 10-state U.S. North Central region. Assuming
80 km as the maximum distance for road haulage to the biorefinery from
the field, we identified 32 potential biorefinery placements each
capable of supplying sufficient feedstock to produce at least 133
× 106 L y-1. In total, ethanol production from marginal lands
could produce ~29 × 109 L ethanol y-1, or about 48% of the 2007
U.S. Congress legislative mandate.
Original language | English GB |
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Title of host publication | AGU Fall Meeting 2010 |
Volume | 22 |
State | Published - 1 Dec 2010 |
Externally published | Yes |
Keywords
- 0402 BIOGEOSCIENCES / Agricultural systems
- 0426 BIOGEOSCIENCES / Biosphere/atmosphere interactions
- 0466 BIOGEOSCIENCES / Modeling
- 0499 BIOGEOSCIENCES / New fields