No abstract

As reported in literature the production of biodiesel should lead to a lower energy consumption than those obtainable with its use. So, to justify its consumption, a sustainable and "low input" production should be carried out. In order to assess the sustainability of Linum usitatissimum, Camelina sativa and Brassica carinata cultivation for biodiesel production in terms of energy used compared to that obtained, the index EROEI (Energy Return On Energy Invested) has been used. At this aim, an experimental field was realised in the south-eastern Sicilian land. During the autumn-winter crop cycle, no irrigation was carried out and some suitable agricultural practices have been carried out taking into account the peculiarity of each type of used seeds. The total energy consumed for the cultivation of oil bearing crops from sowing to the production of biodiesel represents the Input of the process. In particular, this concerned the energy embodied in machinery and tools utilized, in seed, chemical fertilizer and herbicide but also the energy embodied in diesel fuels and lubricant oils. In addition, the energy consumption relating to machines and reagents required for the processes of extraction and transesterification of the vegetable oil into biodiesel have been calculated for each crops. The energy obtainable from biodiesel production, taking into account the energy used for seed pressing and for vegetable oil transesterification into biodiesel, represents the Output of the process. The ratio Output/Input gets the EROEI index which in the case of Camelina sativa and Linum usatissimum is greater than one. These results show that the cultivation of these crops for biofuels production is convenient in terms of energy return on energy investment. The EROEI index for Brassica carinata is lower than one. This could means that some factors, concerning mechanisation and climatic conditions, were not suitable to ensure higher crop yields.

The choice of grape marc as biomass to produce energy has a double purpose. It provides a valid alternative to the handing over to distilleries, which represents a considerable cost for the community and also gives value to a form of agricultural-industrial waste. In this paper, the results of an experiment performed at ERSAF (Lombardy) in their laboratories in Mantova are assessed. A laboratory scale plant was used in order to evaluate the biogas and the methane produced by the anaerobic digestion (AD) of fresh grape marc and to evaluate the role of seeds in the production of methane. The results indicate there have get yields of up to 110 Nm 3 /t sv of methane, with a much faster production rate than with other bio-masses. The inclusion of grape seeds has a positive effect on the production of biogas and methane. With crushed grape marc a higher percentage of CH4 could be reach than to the other tests, suggesting that the grape seeds crushed favours the methanogenesis. Nevertheless the differences between this matrix and that with as such grape marc are not statistically significant.