A method and system for controlling electrical power in a micro-grid, especially during islanding when the micro-grid is disconnected from a main grid is described. A potential load shedding for islanding is determined when the micro grid is connected to the main grid. The potential load shedding is performed when a grid switch that connects the micro-grid to a main grid opens. A frequency based load shedding and a frequency based control of power injections to the micro grid may also be performed. The frequency based load shedding is performed with a faster response than the power injection control during islanding. The frequency based power injection control is performed with a faster response than the frequency based load shedding when the micro grid is connected to the main grid. A load shedding controller, an energy storage controller and methods performed by the load shedding controller, and the energy storage controller, respectively, is also provided.