A power inverter system includes a plurality of power inverters such as solar inverters receiving power from at least one energy source. Each power inverter includes algorithmic maximum peak power tracking (MPPT) software or integrated MPPT firmware to calculate its own potential real power. A controller is in electrical communication with selected power inverters that are operating in curtailed modes of operation and commands each selected power inverter to shift its power production duties and to perform MPPT sweeps. Each selected power inverter then calculates its own potential real power capability in response to corresponding MPPT sweep data. The potential real power capability information is received by the controller that transmits the information to a power utility allowing the power utility to more efficiently utilize real and reactive power available by the plurality of power inverters