Abstract:As a better energy storage method,energy storage battery gets more and more attention in solving the problem of wind and photovoltaic energy curtailment. However,the economic status of battery energy storage station ( BESS) is not clear, and it is difficult to carry out the large - scale applications. An auxiliary service delivery model is proposed,in which BESS and conventional units bid against each other. Market efficiency analysis model of BESS is established,and according to the calculation of the model,the sensitivity of BESS investment returns is analyzed in Microsoft Office Excel 2007,which can provide an engineering economic reference for the planning project of BESS.