IX International Scientific Symposium "Farm Machinery and Processes Management in Sustainable Agriculture", Lublin, Poland, 2017 DOI: 10.24326/fmpmsa.2017.51 284 ENERGETIC EFFICIENCY OF SALIX VIMINALIS PLANTATION Olga ORYNYCZ, Artur CHODORSKI, Andrzej WASIAK Bialystok University of Technology, POLAND E-mail of corresponding author: o.orynycz@pb.edu.pl Keywords: willow, salix viminalis, EROEI, energetic efficiency ABSTRACT Energetic efficiency, based on a version of EROEI indicator, of salix viminalis plantation is estimated for realistic tillage technology. For different plantation sizes, different sets of machines are selected for performing agro-technical operations. Obtained results are dependent upon plantation size, and characteristics of technical devices applied. Potential values of energetic efficiency are rather high, but it has to be taken into account that the study is confined to the limited number of operations corresponding to strictly agricultural operations. Addition of other steps in production system is supposed to decrease final values. INTRODUCTION Biomass became considered as an alternative source of energy that might replace fossil fuels (at least for some time). This idea results of two factors: first is expectation of sc. “oil peak” – that implies possible shortages of resources. and the second widely discussed climatic effects of use of the fossil fuels. Exploitation of biomass seems to mitigate the both threads mentioned. The energetic use of biomass various origins (both wild or planted) requires inputs of energy on various steps of production. Therefore, it is important that sum of the energy inputs, given to all steps of production, does not exceed final amount of energy obtained from biomass. The effects of biofuel use for sustainability of agriculture have been recently discussed by Wasiak (2016). The characteristic describing energetic efficiency of particular energy producing system under the name EROEI was introduced by Cleveland et al. (1984), Murphy at al. (2010), Murphy et al. (2011) and also Zhang and Colosi (2013). The later Authors indicated, however that various calculation procedures being used might cause discrepancies in results and cause ambiguities of interpretation. Various analyses concerning energetic use of biomass were also published (cf. Field et al. (2007), Mediavilla et al. (2013), Arodudu et al. (2014) and Liu (2017). Recently also Pickard (2014) discussed the applicability of the EROEI to situations of modern technology and introduced some modifications. The following formula was proposed for any system used to convert some material resources onto energy:  =     +∑   +   (1) where Eout – is the energy obtained at the end (exit) of the system, Ecr – is energy needed for creation of the system, Eliq – is energy needed for liquidation of that system. The Ein denotes one of many possible inputs of energy needed for subsequent steps of converting the particular resource or byproduct finally leading to energy. Obviously the EROEI indicator is a dimensionless quantity. This formula was used by Wasiak and Orynycz (2014) as well as Wasiak and Orynycz (2015) in formulation of the model for energetic effectiveness of agricultural subsystem being the part of biodiesel production system. In this case it was assumed that energetic efficiency indicator, ε, is computed for already existing system, liquidation of which is not planned within the period of consideration. Therefore, the formula assumes form: