As the finite nature of the world's fossil fuel resources becomes more apparent, focus must be shifted to other forms of renewable energy sources. Fast growing plants are potential sources for producing a useable grade of ethanol or biogas for energy production. Potential plants to use as sustainable energy sources include trees, certain grasses, crops such as corn and sugarcane, and aquatics such as the water hyacinth and algae. Aquatic plants have the benefit of not requiring fertile land to grow, and thus do not take precious space away from food crops. Also, the harvest frequency for aquatics tends to be on the order of days, whereas the frequency for trees and crops are on the order of years and months. While algae grows faster than water hyacinths, it is difficult to grow algae at maximum rates outside the lab, and algae is much more difficult to harvest. The plentiful availability, low cost, and rapid growth of water hyacinths make them an ideal candidate for a biofuel, particularly in developing countries.

Preliminary work has been done to thermodynamically determine how much energy could be produced by a water hyacinth on a per-plant basis. Additionally, work is in progress to develop process steps and complete an economic analysis to determine the feasibility of a cellulosic ethanol production plant using water hyacinths as a feedstock.

Future work would be focused around answering the following three questions: 1.) Is it more efficient to use water hyacinths to produce ethanol or biogas? That is, which process produces a greater net amount of energy, after all pre-treatment and refining processes have been accounted for? 2.) How can pretreatment be modified to make it less expensive, and what enzymes / conditions can be used? 3.) Should a combination of water hyacinths and another plant (i.e. switch grass) be used to produce a better fuel?

Attempts will be made to answer these questions through a variety of experiments. Water hyacinths will first be obtained and cultivated. An experiment will then be done to determine what is produced when the plant is simply allowed to rot through composting. Further experimentation will then be done with composting, pressing, drying, chopping, and different methods for pre-treating the water hyacinths using different enzymes and acids to produce ethanol. Experiments should also be performed using microbes and other methods to produce biogas.

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