Life-cycle inventory to assess and analyze bio-diesel production in South Africa

Biofuels, just like fossil fuels, are also associated with various environmental impacts along the production- consumption chain. Those impacts need to be attributed to different products, as biofuel production generally yields one or more co-products, like animal fodder or soymeal, or may be a co-product of some other, higher-valued process, like bagasse from sugar cane for heat or electricity production. Life cycle assessments impacts of biofuels are usually studied in a comparative manner, in order to analyse which alternative amongst fossil or bio-based options has the lesser environmental burden.The inventory analysis shows that the inputs and outputs of the farming unit process are sensitive to the type of crop and region of produce. Water usage is a highly variable parameter, which emphasises the importance of rainfall and irrigation to the overall burden of the biodiesel system on water resources. Crop yields may differ by a factor of two, which is a significant difference in terms of land and non-renewable energy resources requirements. The oil and meal/ca ke content of the seed proves to be the most important parameter that influences the initial unit processes of the value chains.