Biomass Gasification based Combined Cycle Plant for Small Scale Generation: Part A-Energetic, Environmental and Economic Analyses

Energetic, environmental and economic (3-E) analyses of a small scale biomass integrated gasification combined cycle (BIGCC) plant are performed and reported in this current study. The plant is consists of a topping gas turbine (GT) block with fixed 500 kW_e output and a bottoming steam turbine (ST) block with variable electrical output. Variations of topping cycle pressure ratio (r_p=4-12) and gas turbine inlet temperature (TIT=900-1100 °C) as major plant operational parameters on the 3-E performance of the plant are measured. Base case performance (r_p=4 & TIT=1000 °C) of the plant reveals that the plant can deliver electricity of about 870 kW at base case with an overall electrical efficiency of about 36.5 %. Electrical specific biomass consumption is about 0.6 kg/kW_eh and specific CO₂ emission is 0.93 kg/kW_eh at this thermodynamic state of operation. Overall electrical efficiency increases and specific CO₂ emission decreases simultaneously with increase in r_p. Also higher TIT yields in better performance of the plant, in terms of efficiency and emission. Economic analysis of the plant explains that the unit cost of electricity (UCOE) value is 0.119 $/kWeh at base case. It is also observed that value of UCOE is minimized at r_p=8 for all TITs. Also at higher TIT, the plant offers lower values of UCOE for considered range of pressure ratio. (paper)