Abstract: A method for controlling a stand-alone modular microgrid unit, including: detecting connection between the microgrid unit and a first power source having a first capacity and a second power source having a second capacity larger than the first capacity; detecting a power demand of a load connected to the microgrid unit; in response to a total power demand from loads electrically connected to the microgrid unit falling below the first capacity, controlling the first power source to operate in a power supply mode and supplying power to the load; in response to the total power demand exceeding the first capacity, disconnecting the load from the microgrid unit, controlling the second power source to operate in a power supply mode, and in response to the second power source producing a threshold amount of power, electrically connecting the load to the microgrid unit and supplying power to the load.