Energy demand and usage is continuously increasing with the development of emerging economies like China and India. Present sources of energy, largely fossil fuels, are not sufficient to meet these increasing needs. Fossil fuels (oil, gas and coal) are associated with pollution and emission of greenhouse gases, which are harmful to the environment. As a result, global warming and climate change have taken centre stage in world summits; notable is the December 2009 United Nations Climate Change conference in Copenhagen.
With increasing concerns on global warming and its attendant effects on climate change, there is a gradual shift of technologies towards greener options. The use of fossil fuels is further bedevilled with its scarcity and access issues, hence, a conscious shift towards renewable energy. Renewable energy options include solar, wind, geothermal and biomass. These energy options are critical to the protection of the environment and energy sustainability. Currently, the biggest contribution to the world's renewable energy mix is biomass. Biofuels is becoming increasingly important for transportation because it is providing the much-needed green option to fossil fuels. A recent publication stated that it could reduce carbon emissions by as much as 50-60%.
Biofuels are fuels derived from organic sources (biomass). This paper discusses the sources of biofuels and its classifications into first, second and third generation biofuels. It also gives an overview of associated technologies used in conversion of biomass to biofuels and raises awareness on its economic, environment and technical benefits, as well as issues and challenges surrounding its use as a green energy option.