trends and future of sustainable development - TransEco

Comparing with energy uses in Campania region and Campania agriculture, bioenergy frommarginal lands only covers a small amount of the energy demand and these results cannot besignificantly improved by increasing the cropping intensity (machinery, fertilizers).Concerning the economic assessment, the required investment consists of both direct and indirectlabor (services) and it does not include the cost of fuels used nor other costs for indirect fossil energysaved, because a fraction of the energy delivered is assumed to feedback the production process in orderto make it independent from fossil energy input (a pre-condition for process sustainability).Table 2.Energetic evaluation for low and high input B. carinata cropping systems. Data arecalculated for biodiesel production and heat generation by combustion of straw andcake meal, considering the total selected area (44,998 ha).Energy Invested forprocess (J/yr) (a)Usable EnergyDelivered (J/yr) (b)Net Energy Delivered(J/yr) (b-a)Ratio b/aLow Input 7.87E+14 1.74E+15 9.56E+14 2.21High Input 1.30E+15 2.33E+15 1.03E+15 1.79The total NED from Table 2 corresponds to 22,800 t of oil equivalent in the case of low intensitycropping and to 24,700 t of oil equivalent in the case of high intensity cropping (1 t oil equivalent =4.186E+10 J). Considering that the average oil cost was 61.25 €/barrel (0.45 €/kg in the year 2010,www.oil-price.net), it is possible to calculate the saving rate of economic investment in terms of fossilfuel not used. As shown in Table 3, the net economic balance is negative for both low and high inputcropping systems and the economic investment required is respectively 3.83 and 4.24 times higher thanthe economic savings associated to the oil not used thanks to the NED in the form of biodiesel and heat.Table 3.Economic evaluation for low and high input B. carinata cropping systems. Data arecalculated for biodiesel production and heat generation by combustion of straw andcake meal, considering the total selected area (44,998 ha).Economic investment(€/yr) (a)Saving rate ofeconomic investmentof produced energy(€/yr) (b)Net Economic ( €/yr)(b-a)Ratio a/bLow Input 3.97E+07 1.04E+07 -2.94E+07 3.83High Input 4.75E+07 1.12E+07 -3.63E+07 4.24The poor energetic and economic performance achieved within the previous case study is the startingpoint of the biorefinery approach. The worth of biorefinery processes relies in their ability to exploit alarger fraction of available substrate and generate higher value added products than just energy. Suchproducts seem to be potentially capable of providing higher income and energy replacement value(indirect energy savings from alternative fossil-based chemistry). The enhanced economic performanceof a biorefinery compared to a bioenergy system was verified previously (Fahd et al., 2011, submitted)but it is not shown here: considering the total economic income from a biorefinery chain includingseveral chemical products that can be separated and sold to the market, the economic investmentneeded results to be lower (the ratio of gross income to costs is about 1.8:1). While cropping for50