Olga Orynycz

Formulation of a model for energetic efficiency of agricultural subsystem of biofuel production

Fluxes of energy occurring during subsequent agro-technical operations are evaluated in a deterministic mathematical model of “energetic” plantation aimed towards biofuel production. The agro-technical production system is considered as a part of larger system including industrial part processing crops to biofuel, but at this stage of research is considered separately. The scale of production, determining the demand of industrial part of the system is implicitly considered, and the effects of such interaction are indicated. The derived efficiency indicator, principally corresponding to EROEI, depends upon the yield of plantation and technical characteristics of machinery being used, it also indicates that one of the most important factors decreasing energetic efficiency of plantation is transport of goods and machinery outside of cultivated fields.

THE EFFECT OF EXTERNAL TRANSPORT ON ENERGETIC EFFICIENCY OF BIODIESEL PRODUCTION

In several our publications energetic efficiency of biofuel production was defined as a ratio of the amount of energy obtained in a form of biofuel to the sum of energy contributions necessary to conduct production processes on all the production stages. It was also shown that such a definition enables subsequent inclusion of production steps due to additivity of reciprocals of energetic efficiency determined separately for each step. In the present work, several scenarios of the transport of biomass between plantation and industrial facility converting biomass into biofuel are considered, appropriate values of energetic efficiency are computed and compared. The analysis is confined to biodiesel production based on rapeseed. The results show substantial differences caused by various approaches to that stage of transport.

The Effects of Biomass Transport Between Plantation and Industrial Facility on Energy Efficiency of Biofuel Production System

Production of biofuels requires transportation of substantial amounts of biomass between plantations and industrial facilities that converts this biomass onto biofuel. This transport might strongly affect energetic effectiveness of the whole production system. Basing on computer model, developed in our earlier works, the contributions of the energy consumed in various transport solutions are analyzed, and their effects on the energy efficiency are estimated. The dependencies of the energy efficiency upon technical characteristics of transportation means are shown for several solutions of production organization. Conclusions suggest optimal choices of transportation means, and transport organization as dependent upon the type and the size of a plantation.