Renewable Resource: Biomass and Biofuels. What is biomass? Any organic matter that can be used for...
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Transcript of Renewable Resource: Biomass and Biofuels. What is biomass? Any organic matter that can be used for...
Renewable Resource: Biomass and Biofuels
What is biomass?
• Any organic matter that can be used for fuel.– Wood = #1 biomass fuel used globally.– Crops, seaweed, compost, animal waste
• Biomass get energy from sun through the process of photosynthesis.
US biomass
Biofuels:• Biomass that is altered into the form of
combustible liquids (ethanol or biodiesel)• Reasons behind push for biofuels:– Abundance of biomass• These plants can be grown throughout the world.• Would help us get away from foreign oil imports
– Reduce overall impact on climate change.• Since plants are part of the fast carbon cycle they would
have no net increase in CO2 in atmosphere
– Little impact on current infrastructure
But biofuels aren’t all they are cracked up to be…
• If biofuel production is done on a large scale then a decrease in biodiversity may occur.– Clearing of natural land to create biofuel crops– Soil erosion through large scale clearing– Increase in food prices– Nutrient leaching of soils.
• Increased water use in arid regions• Alternate forms besides corn can be expensive
THE FOLLOWING SLIDES ARE THE PROS AND CONS OF VARIOUS BIOFUELS
Biodiesel
PROS• Decreased the waste stream
from various restaurants because used the waste oil from cooking.
• Easy to convert gas cars to biodiesel cars, and diesel cars would need no alteration.
Cons• Requires government
subsidies to be done on a large scale
• If plants are grown solely for this purpose than large land areas are needed for crops
• Increase fertilizer and pesticide runoff
• Energy needed in the conversion to usable energy
Produced from vegetable oil from soybeans, rapeseeds, sunflowers, oil palms, jatropha shrubs.
Corn ethanol
PROS• Currently being produced
on commercial scale in the US.– E10 = 90% gasoline and 10%
ethanol– E15 = 85% gasoline and 15%
ethanol
CONS• Large government subsidies
to make commercial scale ethanol competitive
• ENERGY INTENSE process to distill ethanol
• Costly• If all corn were used to
create ethanol we would still only create about 18% of required energy.
Conversion of plant starches into simple sugars that can be made into ethanol.
Cellulose
PROS• Uses the “waste” of the
plants and not edible parts• Could utilize 80% of the
waste • Create 30% US
transportation fuel
CONS• Cellulose is a complex sugar
that is extremely tough to break down.
• Only one commercial enzyme available to break down and it is expensive.
• Environmental impact removes nutrients from soil since they aren’t left to decompose.
Uses the waste material of plants (husk, stems, non edible parts)
Algae
PROS• More efficient at
photosynthesis than plants.• Can be grown in almost any
area• Can utilize waste water
CONS• If grown in open surface
water may impact other organisms.
• Require a great deal of nitrogen and phosphorus, which can pollute other water supplies.
• Very energy intense to break the cell walls
SYNTHETIC ORGANISMS
PROS• DNA technology has come a
long way and we can alter genes to work in our favor
CONS• Costly• We don’t know the long
term impact and if other genes can react.
Overall
• Biofuels are not an ideal solution to supplying our transportation energy needs.– Costly and would not be able to compete without
great government subsidies– Energy intense process so become a negative
energy gain.– Quantity and production, there is no way to create
an equivalent amount of energy required for fueling our cars.