trends and future of sustainable development - TransEco

ESI 0.02 0.02 0.14 0.14% Renewable 2% 2% 11% 11%Climate changeGlobal warming (g CO2-equiv/g) 2.33 0.19 1.24 0.55Global warming (g CO2-equiv/J) 6.40E-05 2.36E-05 3.30E-05 3.30E-05Global warming (g CO2-equiv/€) 2.59E+03 2.59E+03 1.58E+03 5.21E+03Acidification (g SO2/g) 9.12E-03 7.57E-04 3.92E-03 1.73E-03Acidification (g SO2/J) 2.50E-07 9.24E-08 1.05E-07 1.05E-07Acidification (g SO2/€) 10.10 10.10 5.00 16.50Eutrophication (g PO4/g) 8.91E-04 7.40E-05 4.10E-04 1.82E-04Eutrophication (g PO4/J) 2.45E-08 9.03E-09 1.09E-08 1.09E-085. Discussion and ConclusionsThe energy and environmental performance of bioenergy (biodiesel and heat) production chain from B.carinata was found to be hardly suitable at the level of Campania regional agriculture, due to the factthat the economic cost of the whole process exceeds the value of the saved fossil fuels, even if heat fromcombustion of straw and oilseed cake meals are accounted for in addition to the biodiesel production.Results show that the net profit is very small in energy terms and that there is no profit at all ineconomic terms. Instead, if agricultural residues are exploited for the extraction of chemical buildingblocks, such as ethyl levulinate and formic acid, both the energy and the economic balances areimproved, due to the high added value of biochemicals. In the biorefinery case, biofuels result to be lessaffected by economic unfeasibility: if residues are considered as still useful substrates, the viability of abio-based process increases. Furthermore, by converting waste and residues (also from foodmanufacturing industry and urban systems) into value added chemicals, combustion and landfilling areavoided and additional energy, economic and environmental burdens are prevented, making the benefitfrom the biorefinery line even larger. The entire utilization of agricultural residues in order to extractboth bioenergy and bioproducts within a biorefinery concept definitely improves the environmental andeconomic performance of bio-based feedstocks. The biorefinery option, in fact, takes advantage of thelargest market value of biomaterials and of the need for proper disposal of agricultural and agroindustrialresidues. Nevertheless, it is still dependent on fossil fuel inputs and therefore not easilydecoupled by the trade-off of economic costs, energy demand and land availability. The economicfeasibility is thus driven by the still low fossil energy cost as well as by the inclusion as credits of thesavings generated by having identified a profitable alternative to agro-industrial waste disposal. Toavoid, or at least decrease, the fossil fuels dependence, the production process needs to be redesignedthrough a major integration among different steps, minimizing transportation expenses and exploitingthe locally available resources (bio-fertilizers, additional residues, potential users of the products).52