Alternative fuels for diesel engines are becoming increasingly important due to diminishing petroleum reserves. The U. S. Energy Information Administration declared that total world energy consumption in 2005 was 488 EJ (exajoule, 1018J) or 463 Quad (quadrillion Btu, 1015 Btu). World consumption is expected to surpass 60% increase in energy consumption or equivalent to 650 EJ by 2025, and this value reflects the degree of industrialization, efficiency of primary energy source used, and energy conservation (Energy Information Agency 2007). Currently, available fossil fuel sources are estimated to become depleted in the next century, with petro­leum reserves depleted within 40 years (BP 2005; Energy Information Agency 2007). As a consequence, crude oil prices have risen from less than $20/barrel in the 1990s to nearly $100/barrel in 2007 (Kinney and Clemente 2005).

The idea of using plant oils as fuel was first substantiated by E. Duffy and J. Patrick in 1853 and tested on engines by 1893 by R. Diesel (Feofilova et al. 2010) using peanut oil. R. Diesel stated in his speech at the Great Britain Technological Institute in 1912 “the use of plant oils as fuel for cars was insignificant now but by time it may become as important as coals and oil products now” (Feofilova et al. 2010). Amazingly nowadays, biodiesel is gaining more importance as an alternative fuel, and the production of biodiesel increased significantly. From 1998 to 2008, the European countries increased the production of biodiesel 33 times higher (475 thou­sand tons up to 16 million tons) followed by United States with two million gallons in year 2000 to 700 million gallons in 2008. Recently, in developing countries (China, Brazil, and Indonesia), development of biodiesel fuel became important and increased tremendously including Malaysia (Feofilova et al. 2010).

Biodiesel can be used in diesel engine without major modification to the engine due to similar properties to fossil fuel (Puhan et al. 2005; No 2011). Biodiesel refers to a nonpetroleum-based diesel fuel consisting of short-chain alkyl (methyl or ethyl) esters that can be made by transesterification of vegetable oil or animal fats. Biodiesel has attracted more and more attention in recent years because it is biode­gradable, renewable, and environmentally friendly. Biodiesel fuel produced on a sustainable basis offers the benefits of energy independency and security, economic and social cohesion (Howell and Jobe 2005), and being environmentally friendly ( Zhang et al. 2003). These factors have created the driving force and motivation for this alternative fuel-biodiesel production.

The utilization of biodiesel possesses several distinct technical advantages and disadvantages compared to petro-diesel (Table 8.1). By considering the positive and negative effects, biodiesel is still considered as a clean fuel that can combat global warming and stabilize the climate through the reduction of CO2 emissions (Drapcho et al. 2008; Arent et al. 2011; Meunier 2007; Ellington et al. 1993) in long term, and researchers are continuously finding alternatives and develop technologies to mini­mize the cost of production. Furthermore, the utilization of biodiesel would largely enhance the commercial value for fats and oils, the need to build biodiesel plants, and the employment of human capital to operate these plants. Thus, using biodiesel

Table 8.1 List of advantages and disadvantages ofbiodiesel as engine combustion fuel compared to petro-diesel (Meher et al. 2006; Demirbas 2009)

Disadvantages

would gain economic benefits for farmers, local communities, and the nation as a whole. Increased utilization of biodiesel results in significant economic benefits for both the urban and rural sectors, as well as the balance of trade (Howell and Jobe 2005).