Optimal thermal power plant selection for a tropical region using multi-criteria decision analysis

•Detailed thermo-economic and environmental impact analyses of 19 power plants.•Development of novel integrated plant configurations (IPP) from existing plant.•Optimal plant selection using multi criteria decision analysis-TOPSIS.•Modification of the conventional TOPSIS algorithm to reduce steps/procedure.•Selection of optimal plant configuration for a tropical region. This research presents thermo-economic and environmental impact analyses of nineteen thermal power plant configurations for electricity generation. From the results of the analyses, appropriate plants’ parameters were carefully chosen and used in the multi-criteria selection of the optimal plant configuration. The thermodynamic performance criteria include net power output, specific fuel consumption, inlet air temperature, and efficiencies, among others. Environmental considerations include the emission rates of CO, NOx, CO2, stack exit temperature factors and sustainability indices of the various power plants. Economic assessment includes life-cycle cost (LCC), annual sales return (ASR), levelized cost of electricity (LCOE), breakeven point (BEP), and net present value (NPV). The optimal plant selection was conducted using the TOPSIS method and the novel modified-TOPSIS developed in this study. Results showed that the integrated gas-, steam- and organic Rankine cycle power plant with absorption refrigerator for compressor inlet air cooling and chilled water for cooling the steam and ORC condensers, is the best plant option with a relative closeness of 0.888 (closest to 1). Parametric investigations showed that NOx emission increased while CO emission decreased with increased combustion flame temperature. Annual capital, operating and maintenance costs of the plant with wet cooling tower increased with ambient wet-bulb temperature.