Thermoeconomic evaluation of three proposals for the energy cogeneration unit powered by natural gas, biogas, or syngas

Abstract

This study uses thermoeconomic analyses to compare proposed cogeneration units that use alternative internal combustion engines operating with three possible fuels: natural gas, biogas, or syngas. The technical basis of the study is thermodynamics, which enables the identification of losses and the determination of system efficiency through energy and exergy analyses conducted with the Engineering Equation Solver software. The thermodynamic tools reveal the technical potential of each energy cogeneration unit to assist the economic–technical viability analysis. The study indicates how an energy cogeneration installation with high cooling demand in commercial and industrial enterprises reduces energy costs. In the calculation of the levelized costs of electricity of the cogeneration units, the imputed electricity is the sum of the electricity saved with an absorption chiller with the electrical power produced by motor–generators. This procedure shows that the reuse of heat reduces the cost of electricity, making the hypothetical installations more economically attractive. The levelized costs obtained for syngas and biogas cogeneration units are higher than the levelized cost for the natural gas unit. However, the biogas project stands out since its levelized cost for the cogeneration unit is only six percent higher than the cost obtained for the natural gas cogeneration unit.