Unlike fossil fuels, biofuels are produced from renewable resources.There are less pollutant emissions from biofuels, which don´t contribute to global warming as carbon dioxide released, is taken up by their feedstocks.
Biofuels are generally classified as 1st, 2nd, 3rd and 4th generations:
- 1st-generation biofuels are made from sugar, starch, vegetable oil, or animal fats using conventional technology. These are generally produced from grains high in sugar or starch fermented into bioethanol; or seeds that which are pressed into vegetable oil used in biodiesel. Common1st-generation biofuels include vegetable oils, biodiesel, bioalcohols, biogas, solid biofuels, syngas.
- 2nd-generation biofuels are produced from non-food crops, such as cellulosic biofuels and waste biomass (stalks of wheat and corn, and wood). Common 2nd-generation biofuels include vegetable oils, biodiesel, bioalcohols, biogas, solid biofuels, and syngas. Research continues on second-generation biofuels including biohydrogen, biomethanol, DMF, Bio-DME, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel.
- 3rd-generation biofuels are produced from extracting oil of algae – sometimes referred to as “oilgae”. Its production is supposed to be low cost and high-yielding – giving up to nearly 30 times the energy per unit area as can be realized from current, conventional ‘1st-generation’ biofuel feedstocks.
- 4rth generation biofuels take into account the carbon capture and storage potential of the crops used to produce the required biomass, as well as the energy efficiency of the processing technology that generates the resulting fuel.