Biofuel Production - Is It A Green Solution?

It is clear that we cannot rely on an endless oil supply and as world reserves of oil dwindle we need to consider what impact replacement energy sources will have on the planet. Biofuel has been promoted as one such alternative. The implication is that we will be able to maintain our current lifestyle by using oil substitutes in the same manner as we have done for the past one hundred years.

This is certainly a worthy goal, but how realistic is this and at what cost will this fuel be produced? The basis of biofuel production is the conversion of plant sugars into ethanol, which can then be used as a fuel. There are two broad types of sugars available in plants, and the choice of which to use as the fuel source directly affects the profitability of the fuel generated from the plant.

The first type is simple sugars, with one or two sugar molecules joined together. These are the sugars that we digest from plants, which are we get our energy from. These sugars are mainly present in the fruits of plants. An example of this is the corn cob. This part of the corn plant is high in energy. Making ethanol from this part of the plant is profitable since the sugar molecules are easily converted into ethanol with the help of organisms such as yeast.

The second type of sugars found in plants make up the plant body itself, which is made of long chain tough fibrous material called cellulose. Cellulose is made of the same simple sugar molecules that are found in fruit, but they are joined in a different way and are very difficult to break apart. We know these more difficult to break up sugars as dietary fiber. Cellulose can be broken down into simple sugars with the use of an enzyme called cellulase, though the process is not 100% efficient. Unfortunately cellulase is difficult and expensive to produce commercially which means that ethanol produced from cellulose has a lower yield and costs significantly more to produce per unit of fuel. The great advantage of this though is that any plant matter including paper, timber and cardboard can be converted to fuel. It is not necessary to use food crops with this method.

Almost all current biofuel production relies on plants rich in simple sugars, like the cob of the corn or the sap of sugar cane. Using these crops to make fuel is not a long term solution. Yes they supplement fuel production, but they do so at the expense of food production. When we consider that global demand for food is rising and there is a limited amount of land fit for crop growing, making fuel from food looks pretty irresponsible.

Biofuels may represent a partial solution to our energy needs, but they cannot be produced at the expense of food. Research into improving methods of breaking down cellulose needs to be done. If this can be done efficiently, bioethanol could mean a genuine step toward a clean energy world. - 39468