The inevitable decline in oil production has already forced us to look for alternative fuel sources. Biofuel has been touted as a substitute, but we need to consider the impacts of this approach. Biofuel proponents suggest that by making fuel from plants we will be able to maintain our current fuel-dependent lifestyle.
How realistic is this scenario? We need to consider the costs associated with alternative energy sources. The biofuel concept is that sugars from plants are fermented into alcohols such as ethanol which can be burnt for energy. The sugars that plants produce fall into two broad categories and the treatment of these two types directly affects their profitability.
Simple sugars are the first group. These have up to three individual sugar molecules joined together. When we eat plant material, it is these sugars that we readily digest to give us energy. These are the same sugars that we use to sweeten a cup of coffee or tea. Such sugars are found in the fruiting parts of plants such as apples and corn cobs. Making ethanol from these parts of plants is cost effective and quick, as the sugar is easily converted to alcohol by organisms such as yeast.
The second source of sugars in the plant is in the plant body itself, the tough fibrous material called cellulose. This is comprised of the same sugar molecules present in the fruit, but are bonded together in long strands. These strands are very difficult to break down into simple sugars and involve complex enzymes such as cellulase. These can be produced commercially but this is an expensive process. The result of converting cellulose into ethanol is both a lower yield and a higher cost per unit of fuel, but its great advantage is that any plant matter, even cardboard and paper, can be converted into fuel. There is no need to reduce the availability of food with cellulose conversion.
Presently almost all biofuel production is carried out using the simple sugars from corn cobs or similarly sugar rich plants such as sugar cane. Clearly, by using these crops to make fuel we are reducing the availability of food. With global demand for food rising and prices rising with it, it seems irresponsible to be using what little agricultural land we have to be making oil substitute fuels.
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.
How realistic is this scenario? We need to consider the costs associated with alternative energy sources. The biofuel concept is that sugars from plants are fermented into alcohols such as ethanol which can be burnt for energy. The sugars that plants produce fall into two broad categories and the treatment of these two types directly affects their profitability.
Simple sugars are the first group. These have up to three individual sugar molecules joined together. When we eat plant material, it is these sugars that we readily digest to give us energy. These are the same sugars that we use to sweeten a cup of coffee or tea. Such sugars are found in the fruiting parts of plants such as apples and corn cobs. Making ethanol from these parts of plants is cost effective and quick, as the sugar is easily converted to alcohol by organisms such as yeast.
The second source of sugars in the plant is in the plant body itself, the tough fibrous material called cellulose. This is comprised of the same sugar molecules present in the fruit, but are bonded together in long strands. These strands are very difficult to break down into simple sugars and involve complex enzymes such as cellulase. These can be produced commercially but this is an expensive process. The result of converting cellulose into ethanol is both a lower yield and a higher cost per unit of fuel, but its great advantage is that any plant matter, even cardboard and paper, can be converted into fuel. There is no need to reduce the availability of food with cellulose conversion.
Presently almost all biofuel production is carried out using the simple sugars from corn cobs or similarly sugar rich plants such as sugar cane. Clearly, by using these crops to make fuel we are reducing the availability of food. With global demand for food rising and prices rising with it, it seems irresponsible to be using what little agricultural land we have to be making oil substitute fuels.
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.
About the Author:
Get more information on this important topic in the What Is Biofuel section of Roger Vanderlely's website, www.green-planet-solar-energy.com. You can also read about the associated issue of fossil fuels, how they are produced and what the problems and benefits are of their use.
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