Power generation from fluegas waste heat in a 500 MWe subcritical coal-fired thermal power plant using solar assisted Kalina Cycle System 11

Highlights: • Additional power can be generated from fluegas waste heat by solar assisted KCS11. • Proposed system is more energy and less exergy efficient compared to KCS11. • Proposed system can reduce the CO₂ emission by about 1008.28 tons annually. • There is an optimum operating parameters that yields maximum efficiency. • LCoE of excess power produced by solar heater is 8.80% lower than solar thermal plant. This paper proposes a solar assisted Kalina Cycle System 11 (KCS 11) driven by fluegas waste heat of 500 MW Subcritical (SubC) coal-fired thermal power plant for additional electrical power generation. A computer simulation programme has been developed in MS-Excel and VBA to calculate and optimize system performance at different conditions. Results show that net electric power generation of about 516.52 kWh can be added with main plant generation for improving the plant net energy and exergy efficiencies by about of 0.040% and 0.036% point, respectively. This will reduce the annual CO₂ emissions by about 1008.28 ton. Solar assisted KCS11 is more energy efficient but less exergy efficient compared to standalone KCS11. About 0.76 is the optimum ammonia mass fraction that yields the maximum efficiency at the operating pressure of 17.54 bar. System performance increases with increase in cooling water flow rate and is optimum at 92.80 kg/s. Power generation cost and payback period of the proposed system are about of Rs. 2.163 per unit generation and 12.44 years, respectively. The levelized cost of electricity (LCoE) for additional generation by solar heater is about Rs. 10.99 per kWh which is about 8.80% lower than conventional solar thermal power plant.