Unit 1.2 – Answers

  1. Answer: B. Nearly all current ethanol production in the U.S. uses corn grain for ethanol. In Brazil, sugar cane is the primary feedstock. In other tropical countries, oil seeds are used for the manufacture of biodiesel. These are all first generation biofuels.
  2. Answer: A. Second generation biofuels are derived from cellulosic plant materials. Much of the current research and development work is aimed at second generation biofuels.
  3. Answer: False. There are technical challenges in burning biomass, including feedstock quality, boiler chemistry, ash deposition, and ash disposal
  4. Answer: G. all of the above.
  5. Answer: C. Combined heat and power is the simultaneous production of electricity fand heat from a single fuel source. Overall energy system efficiency is relatively high in CHP facilities because they make use of waste heat that would otherwise be lost to the environment.
  6. Answer: E. Burning woody biomass can help a utility to meet renewable energy standards and cuts back on pollution from coal burning. However, it would increase the amount of materials that would have to be transported, and would decrease boiler efficiency slightly.
  7. Answer: D. Forests are the primary source of woody biomass. Woody material is also sourced from agriculture, as fast growing short rotation woody crops are an agricultural feedstock.  Sawmill waste is not a significant source of woody biomass, and is typically treated as a waste-based feedstock.
  8. Answer: D. These four categories represent types of agricultural based energy crops, whereas the other choices are plants that fall within a single category.
  9. Answer: F.  The use and conversion of waste materials into bioenergy is referred to as waste-to-energy, and diverts material from landfills.
  10. Answer: False. Bioenergy by-products have economic use, and can contribute significantly toward the profitability of a bioenergy enterprise.