Methodologies developed for the analysis, improvement and optimization of energy systems should take into account not only energy use (exergy consumption) and financial resources expended (economics), but the scarcity both present and future of all resources used as well as any pollution of the environment which may occur. Along these lines, a global methodology, which takes these factors into consideration by providing a vehicle for formulating and optimizing an environomic (thermodynamic, economic and environmental) objective, was recently proposed by the authors. This methodology is applied here to a gas turbine cycle with cogeneration taking into account the environmental costs associated with the NOx emissions from the gas turbine exhaust. The results are then analyzed and compared with the results of the thermoeconomic optimization of the same cyle obtained by each of the authors in earlier works.