University of Bath


Biodiesel is one of the major biofuels. It is a mono alkyl ester made through a transesterification process [5]. Biodiesel is a renewable alternative fuel produced from a wide range of vegetable oils (mostly soybean and rapeseed oil) and animal fats. Biodiesel can be used in its pure form (B100) or blended with standard diesel fuel (e.g.B20) [8]. It is a safe fuel in terms of providing energy security and emissions although being not a completely clean burning fuel. Nevertheless, it is less polluting than regular diesel and is biodegradable It can be used in most diesel vehicles with a low level blend.

Figure 6: Plant where esterification occurs [8].

Photo of biodiesel tank and tank truck



· It can be domestically produced from non-petroleum, renewable resources. And can help reduce dependency on imported fuels.


· Can be used in most diesel engines, especially recent ones [8].


· Biofuels are non-toxic and biodegradable [8].


· Safer to handle than conventional diesel [8].


· Because the crops used to make biodiesel take in carbon dioxide when they grow, biodiesel is considered a renewable fuel. It gives a 60% reduction in CO2 well to wheel.


· It helps lubricate the engine itself, decreasing engine wear and tear, therefore increasing engine’s life [12].





· Lower fuel economy and power (10% lower for B100, 2% for B20) [8] .


· Currently more expensive (30%-40% more than standard diesel).


· Biodiesel thickens and freezes at low temperatures [10].


· Biodiesel is not currently widely available [4].


· Biodiesel contains about 8% less energy per gallon than petroleum diesel [5] .

soy-oil-powered public bus

Figure 7: Biodiesel vehicle [12].