Biodiesel - The Renewable Alternative

Biodiesel - The Renewable Alternative

Fuels derived from renewable biological resources for use in diesel engines are known as biodiesel fuels. Animal fats and virgin and recycled vegetable oils derived from crops such as soybeans, canola, corn and sunflowers can be used in the production of biodiesel fuel. Tall oil, produced from wood pulp waste, is another feedstock source. Biodiesel can either be used in its pure state or can be blended with conventional diesel fuel derived from petroleum.
Vegetable oil was used as a diesel fuel as early as 1900, when Rudolf Diesel demonstrated that a diesel engine could run on peanut oil. However, its use as a fuel attracted little attention except in times of crisis such as during World War II and the energy shortages of the 1970s. Increasing environmental concerns, expensive overproduction in European agriculture and changes in government policies have resulted in expanded testing and usage of biodiesel. This issue of the Bi-weekly Bulletin examines the current situation and outlook for the use of biodiesel as an alternative fuel.

Disadvantages of Biodiesel:

The major disadvantage of biodiesel is high production costs. Studies conducted when agricultural commodity prices were much lower than at present and petroleum prices were in the range of US$18 to $20 per barrel concluded that petroleum must rise to over US$40-$50 per barrel to make biodiesel production viable without a subsidy.
One study suggested that the production of subsidized biofuels can only be justified if a high premium is put on the environmental cost of the alternatives. Also highlighted was the very poor energy accounting of biofuel production considering the energy consumed in the manufacture of fertilizers and pesticides to produce the crops plus energy used in cultivating, harvesting, transporting and processing of the crop.
One additional concern is the environmental impacts of increased fertilizer and pesticide usage to increase oilseed production for use in manufacturing biodiesel.
Biodiesel has a higher viscosity than conventional diesel and therefore becomes less useful at lower temperatures. This limits its use in Canada, the northern U.S. and much of Europe. In these areas, biodiesel is marketed as an additive in a five to ten percent blend with conventional diesel fuel.

Benefits of Biodiesel:

The main benefits of biodiesel are increased energy self-sufficiency for importing countries, increased demand for domestic agricultural products, biodegradability and improved air quality, particularly lower sulphur emissions than from fossil fuels. Exhaust emission improvements include substantial reductions in carbon monoxide, hydrocarbons and particulates, although the production of nitrogen gases is similar to regular diesel fuel. Under conditions of increasing demand for diesel, partial substitution of biodiesel for petroleum diesel or blending of the two would help to stabilize the release of greenhouse gases.
Reduced emissions make biodiesel suitable for use in major cities where air pollution is a problem. Also, its lower emissions make biodiesel suitable for use in confined areas such as mines where ventilation is a concern.
Pure biodiesel has low aquatic toxicity and is completely biodegradable in about 30 days. This characteristic substantially reduces the impact of accidental spills and makes it ideal for use in environmentally sensitive areas, including inland waterways. When biodiesel is blended with regular diesel fuel, biodegradation is accelerated to about three times the normal rate of diesel fuel.
Europe, the United States, New Zealand and Canada have conducted extensive tests of biodiesel in trucks, cars, locomotives, buses, tractors and small boats. Testing has included the use of pure biodiesel and various blends with conventional diesel. Results indicate reduced engine wear while performance remains virtually unchanged. Many tests have concluded that the best overall results are obtained with a blend of 20 percent biodiesel and 80 percent conventional diesel.
Although biodiesel is cleaner-burning, some anticipate that this advantage will diminish as progress is made in reducing emissions and increasing the efficiency of combustion from petroleum based diesel fuel. Biodiesel is also competing with other ëcleaní alternative energy sources such as electricity, propane and natural gas in some applications.

A secondary benefit of biodiesel production is that it creates more employment as it is three to six times more labour intensive per unit of production than fossil fuels.


for more info visit.
http://www.enjineer.com