An energy storage system is provided, where the energy storage system may include an energy storage module and a power conversion module. The energy storage module may be configured to generate a target waveform signal on the direct current bus when receiving a black start signal. In this case, the power conversion module may be configured to: detect the target waveform signal on the direct current bus, and turn on based on the target waveform signal. When the power conversion module cannot receive a power-on instruction of an energy management system, the power conversion module may also actively turn on when detecting the target waveform signal on the direct current bus, to implement a black startup. This features low costs and higher applicability.