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Life Cycle Analysis
The environmental performance of products, processes, and
services has become a key societal issue, and many organizations
are investigating ways to minimize their effects on the environment
and improve their environmental performance. One potential tool is
called Life Cycle Analysis (LCA).
LCA employs a systematic methodology to estimate the potential
impacts of different products or services by examining inputs and
outputs from all life cycle stages, from 'cradle-to-grave'. LCA
relies on clearly defining appropriate system boundaries and the
availability of high quality data.
Biodiesel has been proposed as a cleaner burning alternative to
petroleum-derived diesel for on and off-road applications.
Following the latest research from the US, the industry is
confident that biodiesel meets today's energy needs without
sacrificing the ability of future generations to do the same. A
recently published report co-authored by researchers from the
University of Idaho and the USDA, titled "Energy Life-Cycle
Assessment of Soybean Biodiesel Revisited," found that for every
unit of fossil energy needed to produce biodiesel, it returns a
stunning 5.54 units of renewable energy.
This energy-in, energy-out ratio is called 'energy balance' or
'fossil energy ratio'. Biodiesel derived from Soybeans or Rapeseed,
for example, benefits from "free" energy from the sun. The study
also compared biodiesel with other alternative fuels receiving
mainstream attention such as liquefied propane and natural gas. A
comparison with gasoline was also evaluated.
"This study shows the clear trend that biodiesel production
continues to improve when it comes to efficient use of resources,"
said Don Scott, director of sustainability for the National
Biodiesel Board. "No other fuel available comes close to such a
high energy balance."
The objective of the study was to construct a new biodiesel
energy life cycle with 2006 data that reflects current soybean
production and biodiesel plants built after 2002, which make up the
majority of plants producing biodiesel today. Additionally, a
comparison of the three time periods from past studies conducted in
1990, 2002 and 2006 indicated how energy life cycles change over
time. Using data from 2009 or 2010 would likely show an even
greater gain in energy efficiency.
Specifically, the new University of Idaho study found three
critical factors that led to the leap in biodiesel's energy balance
number. First, new data from the USDA and the NBB indicate that
soybean crushing facilities and biodiesel plants have become
increasingly more energy efficient over the years. Second, soybean
farmers have adopted energy-saving farm practices such as minimum
tillage. Thirdly, overall yields of soybeans have
In comparison to the 2009 study, the new study found: the energy
input in soybean agriculture was reduced by 52 percent; the energy
input in soybean processing was reduced by 58 percent; the energy
input in biodiesel production (transesterification) was reduced by
33 percent, per unit volume of biodiesel produced; overall, the
energy input reduction was 42 percent for the same amount of
biodiesel produced, and the addition of secondary inputs, such as
farm machinery and building materials, did not have a significant
effect on the fossil energy ratio.
In addition to improved energy efficiency at processing
facilities, soybean growers have accomplished greater yields with
lower inputs of water and fertilizer per bushel, even as cropland
has declined," said Jim Duffield, USDA senior agricultural
economist who co-authored all three life-cycle analysis studies.
"Biodiesel deserves some credit for this progress. The demand it
creates is helping to drive the new technologies that make American
agriculture more efficient."
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