Thermodynamic performance of a novel solar tower aided coal-fired power system

In this paper, a novel solar tower aided coal-fired power (STACP) system is proposed by introducing a solar reheater. In this system, solar energy is used to reheat exhaust steam from an immediate turbine to improve the operating parameter of a regenerative cycle. The thermodynamic, environment, and economic performances of the STACP system in both power-boosting (PB) and fuel-saving (FS) modes are discussed and compared. Subsequently, the effects of reheat temperature and system power load are investigated. Results indicate that for a 300 MWe coal-fired unit, the solar energy used in the PB and FS modes are 81.82 and 71.69 MW, respectively. Compared with the coal-fired power system, the standard coal consumption rate of the STACP system in PB and FS modes can be reduced by 35.98 and 34.99 g/kWh, respectively, whereas the CO2 emission rate of the STACP system in PB and FS modes can be reduced by 101.79 and 98.99 g/kWh, respectively. The additional equipment cost of a solar field in PB and FS modes are 49.76 and 43.60 million US$, respectively. Moreover, the cost of electricity for power generated by solar energy for both modes is 3.37 US cents/kWh.