This document summarizes information on renewable energy sources from biomass. It provides a history of bioenergy use in the United States from the 1850s to present day. It also outlines various biomass feedstocks and waste materials that can be converted to bioenergy through processes like combustion, gasification, anaerobic digestion, and fermentation. The applications of bioenergy include biofuels like ethanol, butanol and biodiesel for transportation; bioheat for heating buildings; and bioelectricity from combustion or microbial fuel cells.

1. Renewable energy sources
Summary of energy resources consumption in United States, 2004
Source:
USDA-DOE, 2005, http://www.eere.energy.gov/biomass/publications.html.
•By 2030, bio-energy, 15-20% energy consumption

2. Overview
Bioenergy history
Ag wastes and other biomass
Biomass to Bioenergy
Conversion processes
Pros & Cons
Applications
Biofuels
Bioheat
Bioelectricity

3. bioenergy history
1850s: Ethanol used for lighting (http://www.eia.doe.gov/
kids/energyfacts/sources/renewable/ethanol.html#motorfuel)
1860s-1906: Ethanol tax enacted (making it no longer
competitive with kerosene for lights)
1896: 1st ethanol-fueled automobile, the Ford Quadricycle
(http://www.nesea.org/greencarclub/factsheets_ethanol.pdf)
Bioenergy is not new!

4. More bioenergy history
1908: 1st flex-fuel car, the Ford Model T
1919-1933: Prohibition banned ethanol unless mixed
with petroleum
WWI and WWII: Ethanol used due to high oil costs
Early 1960s: Acetone-Butanol-Ethanol industrial
fermentation discontinued in US
Today, about 110 new U.S. ethanol refineries in
operation and 75 more planned
(photo from http://www.modelt.org/gallery/picz.asp?iPic=129)

5. Ag wastes and other biomass
Waste Biomass
Crop and forestry residues, animal manure, food processing waste, yard
waste, municipal and C&D solid wastes, sewage, industrial waste
New Biomass: (Terrestrial & Aquatic)
Solar energy and CO2 converted via photosynthesis to organic compounds
Conventionally harvested for food, feed, fiber, & construction materials

6. Agricultural and Forestry Wastes
Crop residues
Animal manures
Food / feed processing residues
Logging residues (harvesting and clearing)
Wood processing mill residues
Paper & pulping waste slurries

7. Municipal garbage & other landfilled
wastes
Municipal Solid Waste
Landfill gas-to-energy
Pre- and post-consumer residues
Urban wood residues
Construction & Demolition wastes
Tree trimmings
Yard waste
Packaging
Discarded furniture

8. Biomass to Bioenergy
Biomass: renewable energy sources coming from
biological material such as plants, animals,
microorganisms and municipal wastes

9. Bioenergy Types
Biofuels
Liquids
Methanol, Ethanol, Butanol, Biodiesel
Gases
Methane, Hydrogen
Bioheat
Wood burning
Bioelectricity
Combustion in Boiler to Turbine
Microbial Fuel Cells (MFCs)

10. Conversion Processes
Biological conversion
Fermentation (methanol,
ethanol, butanol)
Anaerobic digestion (methane)
Anaerobic respiration (bio-
battery)
Chemical conversion
Transesterification (biodiesel)
Thermal conversion
Combustion
Gasification
Pyrolysis

11. Wet biomass
(organic waste, manure)
Solid biomass
(wood, straw)
Sugar and starch plants
(sugar-cane, cereals)
Oil crops and algae
(sunflower, soybean)
Biomass
Biomass-to-Bioenergy Routes
Ethanol
Butanol
Methyl ester
(biodiesel)
Pyrolytic oil
Biogas
H2, CH4
Fuel gas
Sugar
Pure Oil
Conversion
processes
Electricity
Heat
Electrical
devices
Heating
Liquid
biofuels
Transport
Biofuels and Bioenergy Application
Anaerobic
fermentation
Gasification
Combustion
Pyrolysis
Hydrolysis
Hydrolysis
Extraction
Crushing
Refining
fermentation
Transesterification
Photosynthesis
6CO
2
+
6H
2
O
C
6
H
12
O
6
+
6O
2
co
2

12. Advantages of Biomass
Widespread availability in many parts of the world
Contribution to the security of energy supplies
Generally low fuel cost compared with fossil fuels
Biomass as a resource can be stored in large amounts, and
bioenergy produced on demand
Creation of stable jobs, especially in rural areas
Developing technologies and knowledge base offers
opportunities for technology exports
Carbon dioxide mitigation and other emission reductions
(SOx, etc.)

13. Environmental Benefits

14. Drawbacks of Biomass
Generally low energy content
Competition for the resource with food, feed, and material
applications like particle board or paper
Generally higher investment costs for conversion into final energy in
comparison with fossil alternatives

15. Applications

16. Biofuel Applications: Liquids
Ethanol and Butanol: can be used in
gasoline engines either at low blends
(up to 10%), in high blends in Flexible
Fuel Vehicles or in pure form in
adapted engines
Biodiesel: can be used, both blended
with fossil diesel and in pure form. Its
acceptance by car manufacturers is
growing

17. Process for cellulosic bioethanol
http://www1.eere.energy.gov/biomass/abcs_biofuels.html

18. Why Butanol?
More similar to gasoline than ethanol
Butanol can:
 Be transported via existing pipelines (ethanol cannot)
Fuel engines designed for use with gasoline without modification
(ethanol cannot)
Produced from biomass (biobutanol) as well as petroleum
(petrobutanol)
Toxicity issues (no worse than gasoline)

19. Biodiesel from triglyceride oils
Triglyceride consists of glycerol backbone + 3 fatty acid tails
The OH- from the NaOH (or KOH) catalyst facilitates the breaking of the
bonds between fatty acids and glycerol
Methanol then binds to the free end of the fatty acid to produce a methyl
ester (aka biodiesel)
Multi-step reaction mechanism: Triglyceride→Diglyceride
→Monoglyceride →Methyl esters+ glycerine
Glycerine
Methyl Ester
Triglyceride
Methoxide

20. Biodiesel Production
Biodiesel,
glycerin
Fuel Grade
Biodiesel
Fertilizer
K3PO3
water
Catalyst Mixing
Methanol
Neutralization
Acid (phosphoric)
Biodiesel,
impurities
Methanol Recovery
Crude Glycerine
Recovered
methanol
Wash water
Phase Separation
gravity or centrifuge
Purification
(washing)
Catalyst NaOH
Crude Biodiesel (methyl ester)
Crude glycerin
Excess methanol
Catalyst KOH
Raw Oil
Transesterification
Reaction

21. Biofuel Applications: Gases
Hydrogen: can be used in fuel cells
for generating electricity
Methane: can be combusted directly
or converted to ethanol

22. Bioheat Applications
Small-scale heating systems for
households typically use firewood
or pellets
Medium-scale users typically
burn wood chips in grate boilers
Large-scale boilers are able to
burn a larger variety of fuels,
including wood waste and refuse-
derived fuel
Biomass Boiler
(for more info: Dr. Harold M. Keener, OSU Wooster, E-mail keener.3@osu.edu)

23. Bioelectricity Applications
Co-generation: Combustion
followed by a water vapor
cycle driven turbine engine is
the main technology at
present
Microbial Fuel Cells (MFCs):
Direct conversion of biomass
to electricity

24. Microbial fuel cells (MFCs)
Electrons flow from an anode through a resistor to a cathode
where electron acceptors are reduced. Protons flow across a
proton exchange membrane (PEM) to complete the circuit.
PEM

25. Bio-electro-chemical devices
Bacteria as biocatalysts convert the biomass “fuel” directly to
electricity
Oxidation-Reduction reaction switches from normal electron
acceptor (e.g., O2, nitrate, sulfate) to a
solid electron acceptor: Graphite anode
It’s all about REDOX CHEMISTRY!

26. Microbial fuel cells in the lab
•Two-compartment MFC
• Proton exchange membrane:
Nafion 117 or Ultrex
• Electrodes: Graphite plate
84 cm2
• Working volume: 400 ml
ANODE CATHODE
Membrane
Anode
Cathode

27. Anode
Proton Exchange
Membrane
Cathode
Anode
compartment
Cathode
compartment
Cellulose
β-Glucan
(n≤7)
β-Glucan (n ≤7)
Glucose
Cellodextrin
β- Glucan (n-1)
n≥2
n=1
6CO2 + 24e- + 24H+
Butyrate
4CO2 + 18e- + 18H+
Propionate
Acetate
3CO2 + 28e- + 28H+
2CO2 + 8e- + 8H+
O2
H2O
e-
e-
Not to Scale
Bacteria Cell
Bacteria
Cell Wall
H+
e-
H+
e-
H+
e-
e-
H+