摘要：The contribution of agrobiomasses, as a source of energy, to the reduction of greenhousegas emissions was confirmed by several studies. Biomass from agriculture represents one of the larger andmore diverse sources to exploit and in particular ethanol and diesel have the potential to be a sustainablereplacement for fossil fuels, mainly for transport purposes. However, the cultivation of energy cropsdedicated to the production of biofuels presents some potential problems, e.g., competitiveness with foodcrops, water needs, use of fertilizers, etc., and the economic, energy, and environmental convenience ofsuch activity depends on accurate evaluations about the global efficiency of the production system. In thisstudy, the processes related to the cultivation of energy crops were analyzed from an energy and water costperspective. The crops studied, maize (Zea mais) and sunflower (Helianthus annuus), were identified fortheir different water requirements and cultivation management, which in turns induces different energycosts. A 50-year climatic series of meteorological data from 19 weather stations scattered in the Tuscanyregion was used to feed the crop model CropSyst for the simulation of crop production, water requirement,and cultivation techniques. Obtained results were analyzed to define the real costs of energy crop cultivation,depending on energy and water balances. In the energy crop cultivation, the only positive energy balancewas obtained with the more efficient system of irrigation whereas all the other cases provided negativebalances. Concerning water, the results demonstrated that more than 1.000 liters of water are required forproducing 1 liter of bioethanol. As a consequence, the cultivation of energy crops in the reserved areas ofthe region will almost double the actual water requirement of the agricultural sector in Tuscany
关键词：agroenergy; bioethanol; energy balance; pure vegetable oil; water balance
