Bio-Waste Fired Gas Turbine and Transcritical Co2 Cycle Based Combined Power Plant: Thermodynamic, Economic and Environmental Performance Assessment

The present study is intended to design and analyze a novel and efficient biomass fired combined cycle power plant, employing a topping air turbine block (fixed 500 kW output) and a bottoming transcritical CO2 turbine block (variable electrical output). Thermodynamic analysis reveals that the plant can deliver about 550 kW power with maximum efficiency of about 45%. Exergy analysis of the plant assesses that the majority of the input exergy is destroyed in the combined combustor-heat exchanger (CCHR) unit. Environmental parameter, i.e., sustainability index (SI) of the plant ranges between 1.4 and 1.7, depending on the plant operational parameters. Year-around CO2 savings from the plant is found significant when compared with a conventional coal based power plant of the same generation capacity. Which in turn, saves about 30,000 $ annually, in terms of environmental damage cost. Economic analysis of the plant indicates that unit cost of electricity ranges between 15 and 20 INR/kWh, depending on the operating conditions.