The best description that explains why ethanol has a characteristically low net energy yield is:
B. It takes much energy to produce and utilize ethanol as an energy resource.
Here's why:
1. Ethanol production involves various energy-intensive processes such as growing the crops (like corn or sugarcane) used to make ethanol, harvesting, transportation, and conversion of these crops into ethanol.
2. Additionally, the process of distillation to purify ethanol also requires a significant amount of energy, further contributing to its low net energy yield.
3. When compared to the energy inputs required to produce ethanol, the energy output obtained from ethanol as a fuel is relatively low, leading to its characteristically low net energy yield.
In summary, the energy-intensive nature of ethanol production and utilization contributes to its low net energy yield compared to other energy resources.
