1. Biomass

3. Figure 17.11: Three-stone stove used for cooking in many countries.
Fig , p. 571

4. Introduction Biomass energy = energy from living matter
field crops
trees
algae
agriculture wastes (e.g. manure)
municipal solid wastes
solid (wood), liquid (ethanol), and gas (methane)
potential to provide 4-25% of U.S. energy
storage and collection costs are low
efficient for poorer nations
20% of U.S. is cropland/30% is forest
Biomass might support 1/3 of our transportation energy needs

5. Burning biomass does not increase net atmospheric carbon dioxide levels (i.e. carbon neutral) because the carbon in the food chain cycles in and out of the atmosphere constantly.

6. Fossil fuels, although organic and derived from living matter, are NOT considered biomass because they are not renewable nor are they carbon neutral. The carbon in fossil fuels is (for all practical purposes) finite and when burned increases the net carbon dioxide in the biosphere (and potentially contributes to anthropogenic climate change).

7. Biomass conversion reactions
Photosynthesis- puts energy in
Fermentation
Anaerobic digestion
Combustion
Pyrolysis
Esterification of vegetable oil

8. Bioconversion Biogas Fig. 17-1, p. 546
Figure 17.1: Conversion of biomass into useful fuels.
Fig. 17-1, p. 546

9. Food, Fuel, and Famine Energy efficiency in food production
13% of U.S. energy is used to make food
Corn provides 3x the energy needed to make it
90% of U.S. corn crop is used to feed animals for the meat, pork, poultry industry
A cow uses 100x more energy than it provides
We should eat the corn not the cow!
Compare growing broccoli to buying broccoli.

10. Figure 17.5: Energy used in the production of a loaf of bread.
Fig. 17-5, p. 557

11. Energy justice?
The U.S. could feed millions of people in third world nations if we didn’t feed so many cows
Is using corn to make ethanol making food more expensive?

12. Figure 17.2: Flow diagram for production of ethanol from corn.
Fig. 17-2, p. 549

13. Table 17-2, p. 556

14. Municipal Solid Waste Every year, each American tosses into landfills:
80 million tons of paper
50 million tons of food/yard wastes
20 million tons of metal
10 million tons of glass
25 million tons of plastics

15. Figure 17.6: National waste profile.
Fig. 17-6, p. 558

16. +24,000 tons of garbage each day
the Fresh Kills landfill near NYC is the tallest “mountain” on the east coast
+24,000 tons of garbage each day
2 million gallons of leachate contaminates groundwater each day
Municipal dump in Chile.
p. 559

17. What can we do with our garbage?
Reduce 10% of food cost goes into packaging 50% of waste volume is packaging 30% of household waste is packaging
Recycle 30% of U.S. waste is recycled 45% of all paper is recycled to insulation, bldg. mat. recycling the Sunday edition of the NYTimes would save 75,000 trees! recycling 1 aluminum can saves enough energy to run a television for 3 hours
Incinerate to make energy financially breaking even at best concerns over dioxin and metal pollution in ash

18. Figure 17. 7: Waste-to-energy facility
Figure 17.7: Waste-to-energy facility. The steam produced can be used to drive a turbine-generator or to provide process heat to a nearby customer.
Fig. 17-7, p. 562

19. Construct “secure” landfills
using liners and clay to contain leachate
monitor groundwater for contamination
decomposition can be sped up by bioremediation
biogas can be generated- “garbage in ,gas out”

21. Figure 17. 8: Cross section of a secure landfill
Figure 17.8: Cross section of a secure landfill. Note the multibarrier liner of plastic and clay to protect the groundwater from leachate.
Fig. 17-8, p. 564

22. Figure 17. 4: Fixed-container methane digester
Figure 17.4: Fixed-container methane digester. Family-sized digesters using manure are relatively common in countries such as India and China. In China, an estimated 4.5 million biogas digesters are currently in use.
Fig. 17-4, p. 554

23. Wood combustion
In 1860, 75% of U.S. energy needs were supplied by wood. In 190025% In 19732%
Environmental impacts include deforestation and pollution
Handling wood and ash can be burdensome
Fires can be hazardous

24. Figure 17. 9: Heat transfer from a conventional fireplace
Figure 17.9: Heat transfer from a conventional fireplace. Heat output to house is offset by heat loss as a result of room airflow up the chimney.
Fig. 17-9, p. 566

25. Figure 17.10: Airtight stove, with secondary combustion in the upper chamber.
Fig , p. 567

26. Table 17-4a, p. 569

27. If natural gas costs $1 per therm, what should be the price of a cord of mixed hardwoods to deliver the same Btu?

28. Table 17-6, p. 575

29. Figure 17.3: Energy density of various fuels.
Fig. 17-3, p. 553