The extraction staged heat storage is applied to condensing unit peak shaving

and “three-stage” and “two-stage” heat storage and release structures are put forward based on the principle of energy cascade utilization.The changes of peak shaving range

CO_2 emission and income under different schemes are studied. Taking an ultra supercritical 660 MW unit as an example

the above two heat storage and release structures are compared with the existing “single-stage” heat storage and release structure. The 40%THA working condition is taken as the initial working condition to store heat for No.1

No.2 and No.3 regenerative extraction steam

respectively. The results show that

the peak shaving range of the “three-stage” and “two-stage” structure is 31.5%～45.2%

which is greater than that of the “single-stage” storage and discharge structure. In a heat storage and release cycle

the carbon emission of the heat storage peak shaving scheme is almost equal to that of the control scheme without heat storage

but the carbon quota is less than that of the control scheme

resulting in the reduction of carbon trading income.However

after adding the peak shaving income of each heat storage scheme

the total income is higher than that of the control scheme

and the scheme that “storages extraction steam of the first stage of high pressure heater” with “three-stage” structure has the highest total income.