To achieve multi-point substitution of solar energy and energy cascade utilization

this paper proposes three S-CO2 solar-coal complementary power generating (SCCPG) systems with thermal energy storage units. The thermal

environmental

and economic performances of three schemes are compared

and the changing laws of system performance under different operation loads are revealed. The calculation results indicate that the coal consumption for power generation can be reduced by integrating solar energy to replace partial heat load of the system

achieving energy conservation and emission reduction. Under design condition

compared with S-CO2 coal-fired power generating (CPG) system

the CO2 emission rates of schemes 1

2

and 3 decrease by 14.87

43.62

and 29.20 g/(kW•h)

respectively. Among the three schemes

scheme 2 has the lowest coal consumption rate and CO2 emission rate

and the overall performance of the integrated system is the best. Compared with CPG system

it can save $8 million in fuel cost annually and increase the net present value of the entire lifecycle by $80 million. Under off-design conditions

the standard coal consumption rate and CO2 emission rate of the scheme 2 decrease first and then increase with the decrease of load. When the operation load is 270 MW

the coal consumption rate and CO2 emission rate are lowest. Therefore

tower solar energy is more suitable for replacing the high-temperature range of CPG system

and the optimal operation load rate of SCCPG systems is 90%.