Transcript Environmental challenges: Biofuels

Biofuels
Developed by Beth Morgan
Dept. of Plant Biology
Types of Biofuel: Ethanol
Ethanol can be produced using:
Corn stover
Sugar cane bagasse
Hybrid poplar
Switchgrass
Miscanthus
Biggest Suppliers
Increase in Production
Making Ethanol From Seed
1. Grow and collect grain.
2. Grind kernels into meal.
3. Heat and enzymes convert starch to sugar.
4. Anaerobic respiration by yeast.
5. Alcohol (ethanolº is distilled out of mixture.
Ethanol
Energy Yield
Making Ethanol From Cellulosics:
Cell Wall Breakdown
Making Ethanol From Cellulosics
1. Collection, storage & transportation to refinery.
2. Dirt & debris removed from material and then
shredded into small particles.
3. Heat, pressure or acid treatment. Enzymes in
solution are used to breakdown cellulose,
hemicellulose to sugars. Lignin is removed.
4. Syrup of sugars is filtered from solids.
5. Anaerobic fermentation by bacteria to produce
alcohol (and carbon dioxide).
6. Further enzymatic breakdown of cellulose and lignin.
7. Anaerobic fermentation by bacteria to produce
alcohol (and carbon dioxide).
8. Alcohol is distilled.
9. More water removed.
10. Stored for distribution and use.
Types of Biofuel: Biodiesel
Bio-diesel can be produced using:
Algae
Jatropha tree
Palm oil
Camelina
Making Biodiesel
Waste
Vegetable
Oil
Lye
Methoxide Methanol
WVO
Washed Biodiesel
Water
Biodiesel
Glycerin
Washed Biodiesel
Water
Biodiesel
Biodiesel
BioFuel from Vegetable Oil
Pros: Energy Yield
Pros: Energy Yield
For every unit of fossil energy used in the entire biodiesel production cycle,
3.2 units of energy are gained when the fuel is burned, or a
positive energy balance of 320 percent.
Pros: Energy Yield
Fuel
Gasoline
Diesel
Energy yield
0.805
0.843
Net (loss) or gain
(19.5%)
(15.7%)
Ethanol
Biodiesel
1.34
3.2
34%
320%
(gain is from photosynthesis)
Pros: Reduced Emissions
Emissions of major air pollutants from diesel engines
Cons: Loss of Land for Food
Production
Loss of Rainforests
Water Use Increases
Soil Fertility
Poplar trees
Switchgrass harvest in the Netherlands
Soybean harvest
Price of Corn 
Food vs. Fuel?