A multi-criteria approach to evaluate the natural gas energy systems

This paper aims to select the optimal energetic scenario applied to a consumer with 100 000 inhabitants from the residential–tertiary sector, from the ecological, energetical and economic points of view. A series of seven scenarios based on natural gas has been analyzed. The authors proposed six scenarios for the combined heat and power generation using existing technologies and one scenario for separate generation of the two energy forms. To compare the seven energetic scenarios, the amount of thermal and electrical energy produced by each one had to be the same for a defined time period. To select the optimal energy scenario a multi-criteria NAIADE-based method has been used. Consequently, the optimal energy scenario has been established with respect to criteria groups: ecologic, economic, energetic and global where all criteria groups have been considered. The study results prove that a combined gas and steam turbine cycle is optimal technically, economically and ecologically as it is for each criteria group. A sensitivity analysis has been performed to establish the influence of various parameters in the identification of the optimal energy scenario. For all analyzed scenarios, the optimal energetic scenario is the combined gas and steam turbine cycle.