Multi-objective optimization in energy systems: the case study of Lesvos Island, Greece

The process of decision-making determines the choice of a possible course of action amongst a wide variety of available alternatives. The difficult point in decision-making is the multiplicity of the criteria set for judging the alternatives. The decision maker needs to attain more than one objective in achieving the final goal set, while satisfying constraints dictated by the environment, processes and resources. A multi-objective optimization methodology is applied on the island of Lesvos, Greece, where various renewable energy sources (RES) can be found and could be exploited to satisfy part of the needs of the island's economy. These resources must be examined from all aspects and a case study is performed for Lesvos that involves application of specific mathematical tools that will lead to a set of energy solutions (Pareto set). These solutions will concern the use of various energy sources that will satisfy a multiplicity of criteria (environmental, demand, cost and resource constraints). The research for this mathematical model has led to the creation of a system with two objective functions that work reversely. Considering the existing constraints, a series of solutions is derived providing decision makers the flexibility to choose the appropriate solution with respect to the given situation.