Unit 1.4 – Answers

  1. Answer: e. Producers make decisions about whether or not to grow bioenergy crops based on complex decision making taking into account an array of factors.
  2. Answer: f. Residue removal has been associated with increased soil erosion, soil compaction, loss of soil carbon, and consequent negative impact on soil quality and on associated waterways. Farmers should exercise caution, using sustainable harvest guidelines, in the removal of residue from farmland.
  3. Answer: True. Biotechnology is currently being aimed both at addressing feedstock limitations (e.g., higher-yield, faster growing crops) and at speeding up components of process technologies (e.g., better enzymes, more efficient organisms for fermentation of ethanol).
  4. Answer: F. all of the above elements will probably need to be in place for the bioenergy industry to succeed.
  5. Answer: D. Public policy, in particular, can drive the development of a new industry. Regulatory structures, quality standards, and marketing institutions are all necessary to meet mandated renewable energy goals and to develop a mature bioenergy industry.
  6. Answer: C. Densification reduces storage and transportation costs. Biomass materials must be stored to reduce incidence of decomposition. Pre-treatment is used to break about cellulose so that it can be converted to sugars or starches and then ethanol (not as a means to reduce bulk). Biomass combustion facilities should be co-located, to the extent possible, in proximity to users. Ethanol conversion facilities are typically located in regions where biomass feedstocks are plentiful in order to reduce transportation costs.
  7. Answer: True. The cost of transportation of feedstocks (particularly cellulosic materials) can contribute significantly to the costs of cellulosic ethanol production. To limit costs, most conversion facilities will locate where required feedstock is abundant.
  8. Answer: D. The technologies for converting cellulosic materials into ethanol are being developed, but as yet are costly. As such, industry and government incentive programs are working to move the technology from pilot to commercial scales.