Various embodiments of the teachings herein include an energy management system for a building having power consumption devices, power generation devices, and power storage devices. An example includes: a monitoring unit to acquire information about power generated by the power generation devices, about power consumed by the power consumption devices, and about a respective state of charge of the power storage devices; a management unit to derive information about a flexibility of the power demand of the power consumption devices deployed in the building based on the information acquired by the monitoring unit; and an optimization unit to optimize the power allocation of the power produced by the power generation devices to the power consumption devices and/or to the power storage devices based at least in part on the derived flexibility information of the power demand.

Systems, methods and apparatuses for power systems and energy storage systems are disclosed herein. The system, or part thereof, may be configured to determine an operational plan for controlling device(s) (e.g., an energy storage device and/or a load device) such that the device(s) may increase their power consumption in response to an increasing voltage at a grid connection point thus reducing the probability that the voltage level at the grid connection point rises to or above an upper limit. The system, or part thereof, may identify external conditions that may cause harm to one or more energy storage devices (e.g., a battery pack). A controller (e.g., battery management system, or part thereof) may be used to determine critical external conditions or high-risk conditions based on sensor data, and/or to determine mitigation actions or send alerts. The system may comprise one or more energy storage devices that may be stacked together.