Biofuel vs Fossil Fuel
Cost
Fossil fuels are more expensive as pumping fuel from the ground is a difficult and expensive process, fossil fuels are also limited by availability as it requires millions of years to produce. Thus the availability of fossil fuels cannot keep up with the demand for energy making it more expensive.
Available land area
Due to limited land area it is impossible to grow enough biomass to make biofuels as there is only a limited area of land which can be used for farming etc. The land is also required for growing food not just biomass for biofuels thus it makes it very hard to meet both demands
Biofuels contribute to Global warmingÂ
The energy required to convert biomass to biofuel is more than the energy produced by these biofuels.
At the same time fertilizers are used for the growth of these crops and they contain nitrous oxide that causes global warming
http://biofuel.org.uk/