Biomasses are considered neutral energy sources in terms of greenhouse effects because their combustion does not result in an increase in the concentration of atmospheric carbon dioxide. In fact, given that the quantity of carbon dioxide emitted in the combustion phase is equivalent to that absorbed by the vegetables during their growth, the CO2 cycle is closed. But taking into account the entire life cycle of the combustibles that form the biomass does not result in a nil bal­ance of CO2. In fact, the production, working and transport steps often result in negative impacts on the environment that are determined by energy and mate­rial consumptions which are necessary to sustain the processes. Table 1 lists the carbon dioxide balance for the fuels obtained from the main biomass production spinnerets. The avoided emissions were estimated as a function of the substi­tuted fossil fuel (coal, diesel, methane) by taking into account the respective calorific powers [2, 3].