Energy Chains Optimization for Selection of Sustainable Energy Supply

The notion of energy chain concept has been defined as the trajectory of energy transformations from the fuel source or energy sources to useful energy form to end users. Production of fuels, heat and electricity from different sources is defined by the appropriate energy supply chain. Every single energy supply chain can be uniquely defined by several sustainability criteria. These criteria are: total energy efficiency of production, total exergy efficiency of overall chain, the coefficient of exergy quality for different products at energy chains, economy of production, investment and environmental criteria. Optimal energy supply chain can be chosen by using multicriteria optimization which fulfils the above-mentioned sustainability criteria. This selected energy chain is close to ideal solution. The ideal energy supply chain is formed from the set of energy production ways which are defined from the perspective of sustainability criteria and which have connection with the current status of technologies, economic, environmental parameters, etc. The concept of optimization in practice is usually based on economics until recently, often neglecting all the other consequences of such a decision. Therefore, multicriteria decision making (MCDM) improves the opportunities in assessing the optimal variant of energy chain for defined ranking criteria. Before the optimization process, it is necessary to create a mathematical model for calculation of optimization criteria. Also, for each specific case of energy production, it is necessary to develop appropriate mathematical formulas to describe the energy chain. Numerical verification, all mathematical calculations and modelling have been applied and confirmed on wood biomass supply chain for energy production in this case. The reason for this is complexity of supply chains in the bioenergy and representation of renewable energy sources. For total ranking of energy chain for production of fuel or energy and selection of optimum variant, the multicriteria optimization and VIKOR method were applied. The significance of energy production from renewable energy sources is particularly expressed nowadays. Basically, the most significant part in the process of energy production from energy sources is the supply chain, final conversion of energy in useful form at the energy plant and the distribution process to end users. Due to the fact that there are various opportunities for the composition of energy chains of fuel supply and different ways of energy production, it is necessary to try to make a unique mathematical approach for this problem. With the proposed sustainability criteria and developed mathematical model, it is possible to unify the overall problem of energy supply chains' optimization. The proposed developed method can be used for the optimization of any kind of energy supply chains (electricity, heat, fuels or their mix). All of these are enabled by proper selection criteria for the description of overall energy transformations in energy chains and quality evaluation of the energy produced. The developed approach and mathematical model have a very practical application in the selection of optimal variant of energy production and of course in designing new energy chains.