Why are biofuels important in transportation?
Because some countries have introduced legislation and taxation regimes which promote the use of biofuels in transportation.
In some countries biofuels attract government subsidies (or, equivalently, reduction in taxation). This creates a demand for biofuels, typically alcohol generated by fermenting carbohydrates created by crops by photosynthesis, but also palm oil, soya bean oil and rapeseed oil. The use of biofuels is important in transportation, especially to fleet operators, because of the need to assess the overall lifetime cost of utilizing biofuel.
The short term problem is the reduction in the performance of the vehicle in terms of distance traveled per unit of volume consumed.
The medium term problem is the extra maintenance needed on vehicles and on the distribution network. Without this there are problems with fuel clogging, bacterial infestation and extra corrosion of sealants by the alcohol.
The long term problem in early trials was the impact on the economics of food production. It was found that in some countries farmers could make more money by growing and selling plants for fuel for export rather than for food for local consumption. This rapidly pushed up food prices, resulting in hunger and civil unrest and a resulting backlash against biofuel legislation.
A further problem was found later on in that the first biofuels were produced as an additive to diesel. In combination with reduced taxation on diesel fuel in some countries, this legislation resulted in a drift, for financial reasons, from petroleum naphtha to "bio-diesel" as the fuel of choice.
However, the resulting increase in particulate pollution in urban environments was unacceptable in some countries and the move towards bio-diesel ended there. Nevertheless, in some other countries biofuels are still promoted, and so knowledge of the impact of biofuels in transportation, the environment, and the global economy is important