Biofuels

• Many plants have simple sugars stored as starch, and complex sugars called cellulose and lignin.
  

• Biofuels are an alternative to petroleum and diesel fuels.

• Biofuels are carbon neutral and a renewable energy source
  

What is Biodiesel made from?

• US: Corn, switchgrass, and soybean
• Europe: rapeseed, wheat, and sugar beet
• Brazil: sugar cane
• Asia: Palm oil, miscanthus, sorghum, cassava, and jatropha

Waste to Biofuels Conversion

• Biological waste from agricutlural, forestry and homes can be used to make biogas.  This technology is called second generation biofuel processes.
• Landfills site emit methane gas (biogas) which can be harvested and burned.
  

 Types of Technologies

Biodiesel - oil

• Official name is FAME (fatty acid methyl ester). Biodiesel is produced from the transesterification of oils using methanol. The by-product, glycerine, can be made into soaps.
• The quality of the oil doesn't need to be high (used oil from fast- food resteraunts were used in the Veggie Van)
• Majority of diesel vehicles can run on pure biodiesel (B100)
• Usually made from vegetable oils, although algal biodiesel might be the future)

 Bioalcohol - biomethanol, bioethanol, biobutanol

 Biomethanol

• Usually produced from natural gas.
• Can be produced from biomass. 
• Methanol is an alternative to the hydrogen economy.
  

• First Generation: This method uses the starch in high sugar content plants. However, the majority of the plant (lignocellulose) is not used. The starch is broken down into glucose. The glucose is fermented; similar to the production of beer or wine. However, this method uses food crops which is controversial.
  
• Second Generation: To increase the amount of biofuels that can be produced, the lignocellulose should be used.  Lignocellulosic ethanol is made by degrading the cellulose molecules in a plant by enzymes. The simple sugar molecules are then fermented to make ethanol, just like in first generation bioethanol production. The lignin cannot yet be fermented and is typically burned to power the processing plant.
  
• E10 is most common biofuel mixture. Vehicles can run on pure E100 or with specific mixtures at E85 and E10. Fexible-fuel cars (widely used in Brazil) can used a number of different mixtures) 
• Fischer Tropsch: solid biomass transformed into synthesis gas using high pressure and high temperature. Fuel properties can be adjusted to fit engines which improves combustion and reduces pollutions. (testing phase)
  

A direct replacement for gasoline and can be used in a gasoline engine without any modifications. Biobutanol is made by ABE fermentation (Acetone, Butanol, and Ethanol) and has potentially high net gains.

Pros

• Using waste material from industry (2nd generation) could be carbon positive) 

Cons 

• In practice, biofuels are not carbon neutral. Energy is required to grow the crops and process them into fuel. 
•  N20 from biofuels can contribute to global warming through global cooling.
• Lignin and green constituents cannot be converted into fuel, decreasing the cultivable land 

• Blue Fire Ethanol, Inc - strong acid technology plant site on an existing landfill. 19 million gallons a year.
  
• IOGEN - A enzymatic plant in Canada makes 700,000 litres of ethanol a year. Proposed plant in Idaho 18 million plants annually.
  
• Poet - 125 million gallos of ethanol per year (25% cellulosic)
  
• Range Fues - syngas reforming technology. 40 million gallons of ethanol, 9 mil methanol. Chevron and NREL have teamed up to  
• GreenFuel Technologies has made a bioreactor that uses algae to convert smokestack flue gases to biofuels.

 Sources:

http://www.renewables-made-in-germany.com/en/biofuels/ http://en.wikipedia.org/wiki/Biofuel