Multi-Criteria Optimization Concept for the Selection of Optimal Solid Fuels Supply Chain from Wooden Biomass

Abstract

Production of solid fuels from wooden biomass is defined with appropriate energy chain of supply. Production procedure of solid fuels from wooden biomass, starting with technology for gathering wood residues and residues from logging up by the system of fuel production (system for milling, crushing, chopping, drying and pressing of wood residues), represents the energy chain of supply of solid fuel from biomass. Every single energy chain of supply and production of certain form of solid fuel from wooden biomass can be uniquely defined with three general criteria. These criteria are: energy efficiency of production, economy of production and environmental criteria. Efficiency of production is the relation of overall energy consumption per 1 kWh of heating value of produced fuel. When we talk about the economical aspect of production of solid fuels we take into account all production costs per 1 kWh of heating value of biofuel produced. Forest biomass is scattered and the need for its collection and transport require certain consumption of fossil fuel. Consumption of fossil fuel is needed to run mechanization to collect, transport and prepare biomass. Consumption of fossil fuels causes the emission of GHG. Ecological criteria for the estimation of production process of bio energy can be defined as emission of GHG per 1 kWh of heating value of produced fuel. Besides general criteria to estimate the quality of production of energy from biomass, there are specific criteria. Specific criteria regarding several characteristics are tightly related to applied technologies, potentials and barriers during the use of biomass. This paper analyzes only specific investment in selected chain of energy supply. The paper mathematically describes four characteristic cases of solid biofuel production from wooden biomass. These cases are: production of wooden chips from forest biomass with mobile chipper, production of wooden chips from wooden residues transported from sawmill to processing terminal, production of wooden briquette from mill residues transported into briquette factory, production of wooden pellet from mill residues transported into pellet factory. For overall ranking of energy chain of wooden biomass supply and selection of optimum variant, multicriteria optimization and VIKOR method is used.