A micro grid for an oil field is powered by a utility power grid. A micro grid controller is adapted to prevent excessive or unstable power draw on the utility power grid while allowing uninterrupted power supply for drilling rigs in the oil field. The micro grid controller is adapted to control operation of one or more pieces of electrical equipment on the drilling rigs. The micro grid controller may prioritize operation of the electrical equipment based on relative priority of the operations or based on an operating condition of the drilling rig.