A hybrid energy storage system comprising two or more energy storage units with different energy storage characteristics that are associated with an electric grid comprising one or more electrical buses and a control apparatus for controlling the two or more energy storage units, wherein the control apparatus comprises: two or more power-sharing controller, each of the power-sharing controller corresponding to one energy storage unit, respectively each power-sharing controller configured to generate an individual power-sharing command signal; and a charging-state controller corresponding to each energy storage unit, each charging-statecontroller configured to control charging and discharging of the corresponding energy storage unit through an associated local converter unit, in response to the individual power-sharing command signal generated by the corresponding power-sharing controller; each power-sharing controller comprising: a filter circuit configured to obtain a filtered input signal by filtering the input signal to the power-sharing controller according to a filter response that is tailored to the energy storage characteristics of the corresponding energy storage unit, said input signal reflecting load variations on the electrical grid; and a control circuit configured to generate the individual power-sharing command signal as a combination of the filtered input signal and a steady-state command signal representing a targeted steady-state condition of the corresponding energy storage unit, wherein the input signal as provided to at least one of the power-sharing controllers has a communication latency associated with it, and wherein each of the at least one power-sharing controllers further includes a latency-compensation circuit that is configured to compensate for the communication latency based on predicting values of the input signal as a function of low-latency local grid measurements obtained for the corresponding energy storage unit. two or more power-sharing controller, each of the power-sharing controller corresponding to one energy storage unit, respectively each power-sharing controller configured to generate an individual power-sharing command signal; and a charging-state controller corresponding to each energy storage unit, each charging-statecontroller configured to control charging and discharging of the corresponding energy storage unit through an associated local converter unit, in response to the individual power-sharing command signal generated by the corresponding power-sharing controller; each power-sharing controller comprising: a filter circuit configured to obtain a filtered input signal by filtering the input signal to the power-sharing controller according to a filter response that is tailored to the energy storage characteristics of the corresponding energy storage unit, said input signal reflecting load variations on the electrical grid; and a control circuit configured to generate the individual power-sharing command signal as a combination of the filtered input signal and a steady-state command signal representing a targeted steady-state condition of the corresponding energy storage unit, a filter circuit configured to obtain a filtered input signal by filtering the input signal to the power-sharing controller according to a filter response that is tailored to the energy storage characteristics of the corresponding energy storage unit, said input signal reflecting load variations on the electrical grid; and a control circuit configured to generate the individual power-sharing command signal as a combination of the filtered input signal and a steady-state command signal representing a targeted steady-state condition of the corresponding energy storage unit,