A system for determining power flows in a power plant including an energy storage system (ESS) including an energy storage device and a power generation system comprising a power source includes at least one memory storing a power plant model. The power plant model includes an ESS model including an energy storage device model, a power generation system model, a load model of a load configured to receive power from the power plant, and system relationships between the ESS model, the power generation system model, and the load model. The system further includes at least one processor configured to receive input parameters for the load, determine a power flow rate at a point in the power plant or an energy storage level of the energy storage device at a first time step, and generate a record comprising an indication of the power flow rate or energy storage level.