Assessment of Energy Return on Energy Investment (EROEI) of Oil Bearing Crops for Renewable Fuel Production

As reported in literature the production of biodiesel should lead to alower energy consumption than those obtainable with its use. So, tojustify its consumption, a sustainable and “low input” productionshould be carried out. In order to assess the sustainability of Linumusitatissimum, Camelina sativa and Brassica carinata cultivation forbiodiesel production in terms of energy used compared to thatobtained, the index EROEI (Energy Return On Energy Invested) hasbeen used. At this aim, an experimental field was realised in thesouth-eastern Sicilian land. During the autumn-winter crop cycle, noirrigation was carried out and some suitable agricultural practiceshave been carried out taking into account the peculiarity of each typeof used seeds. The total energy consumed for the cultivation of oilbearing crops from sowing to the production of biodiesel representsthe Input of the process. In particular, this concerned the energyembodied in machinery and tools utilized, in seed, chemical fertilizerand herbicide but also the energy embodied in diesel fuels and lubricantoils. In addition, the energy consumption relating to machinesand reagents required for the processes of extraction and transesterificationof the vegetable oil into biodiesel have been calculated foreach crops. The energy obtainable from biodiesel production, takinginto account the energy used for seed pressing and for vegetable oiltransesterification into biodiesel, represents the Output of theprocess. The ratio Output/Input gets the EROEI index which in thecase of Camelina sativa and Linum usatissimum is greater than one.These results show that the cultivation of these crops for biofuels productionis convenient in terms of energy return on energy investment.The EROEI index for Brassica carinata is lower than one. This couldmeans that some factors, concerning mechanisation and climatic conditions,were not suitable to ensure higher crop yields