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CHAPTER 29 BIOFUELS
GAS FROM GRASS
Will an ordinary prairie grass become the next biofuel?
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GAS FROM GRASS
Will an ordinary prairie grass become the next biofuel?
After reading this chapter
you will know:
About biofuels, their
sources, and trade-offs
About controversies
attached to land
allocation for ethanol
and the potential for
cellulose from plants as a
part of our energy
strategy
Learning Outcomes
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GAS FROM GRASS
Will an ordinary prairie grass become the next biofuel?
Main
Concept
Biofuels offer
potential replacement
for fossil fuels but, like
all alternatives,
require additional
research and
continued discussion
of pros and cons.
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GAS FROM GRASS
Will an ordinary prairie grass become the next biofuel?
Case: Nitrogen is one of the limiting factors
for plant growth. As we adjust to growth
patterns changing with the climate, biomass
production from prairie grasses might be a
potential source for better biofuels than the
croplands we currently use.
Test plots in
Cedar Creek Reserve, Minnesota, have revealed
more than just the role of nitrogen in plant
production. Accidental diversity within test plots
revealed surprising increases in productivity.
Conventional monocultures and the process of
clearing land for crops reduces primary
production and releases CO2 into the
atmosphere.
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Biofuels are a potentially important alternative to fossil fuels
Burning biomass such as
cornstalks and weeds is the way
we've claimed energy from
nature as long as man has used
fire.
Only in recent history have we
shifted our use to non-renewable
fossil fuels.
Increasing our use of biofuels—
those fuels made from biomass—
is one of our current strategies
for reducing fossil fuel
dependence.
Terms:
Biofuels
Biomass
Feedstock
Perennial
Annual
Fuel crops
Bioethanol
Biodiesel
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Biofuels come from unexpected sources
Materials of biological origin can be burned directly or converted to bioethanol or
biodiesel. Direct biomass energy comes from burning waste materials or crops
specifically grown for fuel production.
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Biofuels come from unexpected sources
Materials of biological origin can be burned directly or converted to bioethanol or
biodiesel. Direct biomass energy comes from burning waste materials or crops
specifically grown for fuel production.
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Biofuels come from unexpected sources
Materials of biological origin can be burned directly or converted to bioethanol or
biodiesel. Direct biomass energy comes from burning waste materials or crops
specifically grown for fuel production.
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Biofuels come from unexpected sources
Materials of biological origin can be burned directly or converted to bioethanol or
biodiesel. Direct biomass energy comes from burning waste materials or crops
specifically grown for fuel production.
29
Biofuels come from unexpected sources
Bioethanol is the product of distillation and fermentation. These processes capture
concentrated energy stored in biomass of fuel crops like corn and sugarcane. Since
ethanol is highly corrosive and somewhat less efficient than other biofuels, it is used
mainly as an additive.
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Biofuels come from unexpected sources
Biodiesel is a different kind of biofuel produced from high-oil crops like soybeans
and sunflowers, or from restaurant fry grease.
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Biofuels come from unexpected sources
Biodiesel is a different kind of biofuel produced from high-oil crops like soybeans
and sunflowers, or from restaurant fry grease.
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Biofuels come from unexpected sources
Biodiesel is a different kind of biofuel produced from high-oil crops like soybeans
and sunflowers, or from restaurant fry grease.
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Biofuels come from unexpected sources
Biodiesel is a different kind of biofuel produced from high-oil crops like soybeans
and sunflowers, or from restaurant fry grease.
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Biofuels come from unexpected sources
Collection of used vegetable oil from
restaurants to recycle into biodiesel fuel.
Biodiesel is more energy rich than
ethanol, and can be used directly in
diesel engines.
Another advantage of biodiesel is
that it can take waste that was once
a liability and convert it into an
asset. Small biodiesel cooperatives
are testing the potential around the
country.
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Biofuels come from unexpected sources
Collection of used vegetable oil from
restaurants to recycle into biodiesel fuel.
Garbage and agricultural, industrial,
and food waste can be used to
create a variety of biofuels.
Process
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Biofuels come from unexpected sources
Collection of used vegetable oil from
restaurants to recycle into biodiesel fuel.
Garbage and agricultural, industrial,
and food waste can be used to
create a variety of biofuels.
Product
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Turning grass into gas is less environmentally
friendly than it sounds
The Energy Policy Act, passed by Congress in
2005, required that the country boost its
biofuel production to 7.5 billion gallons by
2012.
Over time, experts realized that the initial
attempts to create biofuels weren’t much
more environmentally friendly than the
fossil fuels they were intended to replace.
Corn is one of the most energy-intensive
crops to grow and harvest.
Another worry is that natural lands are
being converted to farmland for biofuels,
endangering native species. Biofuel crops
also displace food crops and drive up the
price of corn.
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Turning grass into gas is less environmentally
friendly than it sounds
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Turning grass into gas is less environmentally
friendly than it sounds
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Turning grass into gas is less environmentally
friendly than it sounds
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Tilman’s experiments showed the importance of biodiversity
Tilman’s group dried and weighed plants from
their experimental strips to determine how
much biomass was being produced.
Biomass results showed that plots with 16
species of plants were 238% more productive
than monoculture plots.
Biodiverse ecosystems that are naturally
adapted to their environment are the most
productive.
Ethanol is made from starch in one of our
monocrops—corn. We have the infrastructure
in place to ramp up corn production even
though it is not as efficient a source of energy
as other crops and loses productivity without
Terms:
diversity.
Monoculture
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Tilman’s experiments showed the importance of biodiversity
Bioethanol can also be
produced from the
cellulose forming cell
walls in plants.
Cellulosic ethanol
produced from crops like
switchgrass have become
important alternatives to
corn ethanol.
In addition to avoiding
the controversy of food
vs. fuel in land use,
switchgrass is a perennial
and sequesters carbon in
the root system after
harvest.
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Tilman’s experiments showed the importance of biodiversity
Life cycle analysis
comparing low-input,
high-diversity grassland
plants.
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Tilman’s experiments showed the importance of biodiversity
All biofuels produce less
greenhouse gas
emissions than
conventional fossil fuels.
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Research being
conducted to use
algae in production
of pharmaceuticals
inspired a group of
scientists at the
University of
California to look at
the same algae as a
potential biofuel.
Algae are predicted
to generate 30 times
more oil per acre
than other plants
used for biodiesel.
There is another rising biofuel star: Algae
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There is another rising biofuel star: Algae
Algae can be grown as a
foodstock for biodiesels.
Biodiesel is the most
common product, but
the sugars in algae can
also be extracted to
produce ethanol.
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There are many reasons why biofuels have not solved our
dependence on fossil fuels
Ethanol can be produced from the
biological fermentation of any plant
material. Food sources like grains
and sugarcane are easily broken
down by yeast fermentation,
whereas plant material high in
cellulose is more challenging to
break down.
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There are many reasons why biofuels have not solved our
dependence on fossil fuels
Ethanol can be produced from the
biological fermentation of any plant
material. Food sources like grains
and sugarcane are easily broken
down by yeast fermentation,
whereas plant material high in
cellulose is more challenging to
break down.
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There are many reasons why biofuels have not solved our
dependence on fossil fuels
Ethanol can be produced from the
biological fermentation of any plant
material. Food sources like grains
and sugarcane are easily broken
down by yeast fermentation,
whereas plant material high in
cellulose is more challenging to
break down.
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There are many reasons why biofuels have not solved our
dependence on fossil fuels
Ethanol can be produced from
the biological fermentation of any
plant material. Food sources like
grains and sugarcane are easily
broken down by yeast
fermentation, whereas plant
material high in cellulose is more
challenging to break down.
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Multiple solutions will be needed to help replace fossil fuels
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Multiple solutions will be needed to help replace fossil fuels
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Multiple solutions will be needed to help replace fossil fuels
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Multiple solutions will be needed to help replace fossil fuels
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Despite ongoing controversies and setbacks, the future of
biofuels looks bright
Hopes are that if biofuels can be use properly, we can
balance our needs for food, energy, and a habitable and
sustainable environment.
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PERSONAL CHOICES THAT HELP
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UNDERSTANDING THE ISSUE
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UNDERSTANDING THE ISSUE
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ANALYZING THE SCIENCE
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ANALYZING THE SCIENCE
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http://www.biodiesel.org
EVALUATING NEW INFORMATION
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MAKING CONNECTIONS

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