Accelerated by FIT, renewable energy such as photovoltaics had been widely introduced to Japanese power system. The instability and intermittency of RE, however, should be mitigated to maintain stability. The “Demand Response: DR” which controls demand side loads became a key technology. In this paper, a first trial of DR using existing Battery Energy Storage System (BESS) is reported with practical conditions in chapter 3. This paper presents a new trends and operation schemes to utilize existing BESS for DR in chapter 4. First, a method to estimate surplus ability of existing BESS to contribute DR is demonstrated with simulation using recorded real data. Second, a practical approach to consider operational restriction caused by thermal behavior of battery is presented. As a result, the potential of existing BESS against DR is evaluated and its features are discussed from various aspects.