ABSTRACT
To be a viable substitute for fossil fuels and be able to provide an actual alternative to the instable prices and supplies associated to the petroleum- based energy, biofuels need to be economically competitive to present environmental benefits and to ensure a stable production to cover the market 476energy demand. To evaluate whether biofuels provide a better alternative over the fossil fuels they displace, a complete set of parameters must be analyzed, including all the aspects related to their full production and use life cycles. In this chapter, the different biofuels industries energy balances are submitted to evaluation, considering their global inputs and outputs. As inputs, the requirements for the seed growing, the conversion of crops into biofuels, the transporting of the crops to the production facilities, or the productions plant efficiencies are considered. As outputs, the energetic potential of the biofuels and the obtained coproducts of the production process are included. Furthermore, the greenhouse gas emissions and other environmental effects associated to these production systems are also evaluated.
