Currently, fast development of the electric vehicles (EVs) technology has potential to replace the fuel-oil driven conventional vehicles to solve energy, economic and ecological issues. Having increased number of EVs will produce more power batteries at the end of their service life though still useful for other purposes. Therefore, there is big market for the retired electrochemical batteries from EVs for energy storage systems at various scales. The aim of the paper is to analyse the technical and economic potential of fully utilising these retired power batteries for their secondary life. When these batteries reach the 70%-80% of their initial capacities, they do not meet the energy and power requirements for electric vehicles, but they can still generate considerable benefits if they are properly used in applications with lower current rates, such as grid and buildings as the energy storage systems (ESSs). In order to investigate the available value of the retired power batteries, performance tests and theoretical calculation has been carried out. As case study office building, has been used to study the feasibility of retired batteries. Due to the structure of regulated energy price in Beijing, the results show that although the energy consumption increase by 942.5 kWh every year, the cost will save $916.74. However, if the retired power batteries from Nissan Leaf will be used in a single room of 100 m² office building, having occupancy of 10 staff, the total battery cost is $3304.90. The cost of retired power batteries can be covered completely in approximate 4 years and can provide cost savings further on from 5th year. This will be a new and promising direction of development for energy sustainability and environment conservation in the future.