Abstract: Research was made on the new technical solution to huge capacity energy storage in thermal power units, by extracting high temperature steam to heat the molten salt. While the unit operating on valley load required by the power grid, the boiler can keep the load and efficiency on a high level. When the unit are required to increase the load rapidly by the power grid peak load, steam will be generated from the SGS of the energy storage module, which runs back to the turbine to increase the power output. The economical analysis of the solution was made on basis of a typical 60 MW storage package for a 350 MW unit. The solution does not change the flow of superheated and reheated steam in the boiler, does not require any modification to the existing boiler and steam engine, and can ensure the safe operation of the unit and reduce the cost.