Fuel produced on the basis of biomass is often called biofuels. Because the carbon in the fuel comes from biomass and not from fossil sources, the same amount of CO2 that is released during combustion, will bind up again when new biomass is formed. Carbon emissions from these kind of fuels are included in nature’s natural carbon cycle and therefore do not contribute to the greenhouse effect. Because fossil fuel is derived from oil which is pumped up from sources below the surface, the use of this will add new carbon to the atmosphere. Nature is not able to bind up all new carbon supplied, and the proportion of CO2 in the atmosphere increases.
Various types of biofuels will, like all other energy sources have environmental impacts. Some of the consequences would be positive, while others could be negative, for example if rainforests were cut down to make room for the cultivation of biofuel feedstock. Of course it is also essential that biofuels will come out with a total climate benefit when the entire life cycle effects are evaluated. Some biofuels have almost no negative effects on the climate, local communities and biodiversity, while others may have major negative effects entailing that it should not be used. As a result, the consequences for the different raw materials and technologies should be mapped out. Waste as raw material for the production of biofuels will have a minimal negative impact on the environment.
A scientific definition of the various generation biofuels (1G, 2G, 3G) can be described based on the carbon source from which the biofuel is derived as, as follows:
1st Generation – the source of carbon for the biofuel is sugar, lipid or starch directly extracted from a plant. The crop is actually or potentially considered to be in competition with food.
2nd Generation – the biofuel carbon is derived from cellulose, hemicellulose, lignin or pectin. For example this may include agricultural, forestry wastes or residues, or purpose-grown
non-food feedstocks (e.g. Short Rotation Coppice, Energy Grasses, MSW and RDF).