By using steam produced by solar energy to replace low-pressure extraction steam in one stage of the thermodynamic system of thermal power plant

a scheme for increasing thermal economic efficiency has been put forward.The changes of thermal economic efficiency for 600 MW

300 MW

and 200 MW unit have been calculated respectively

results of calculation show that the standard coal consumption rate of three said units being decreased by more than 7 g/(kW·h)

and the steam consumption rate of them by more than 70 g(kW·h).The effectiveness of energy-saving is remarkable.For units with low thermal efficiency

there is a more greater potential for reducing standard coal consumption by using solar energy.