Techniques for detailed monitoring and evaluation of individual subsystems within solar photovoltaic power generation systems are provided. In one aspect, a method for monitoring a photovoltaic system having at least one array of photovoltaic panels and at least one inverter system configured to convert output from the panels from DC to AC includes the steps of: obtaining sensor data from the photovoltaic system; computing an efficiency of the panels and an efficiency of the inverter system using the sensor data; computing an aging parameter for the panels using the efficiency of the panels; computing an aging parameter for the inverter system using the efficiency of the inverter system; determining whether the aging parameter for the panels or for the inverter system exceeds a predetermined threshold level; and taking action if either the aging parameter for the array or for the inverter system exceeds the predetermined threshold level.