NOVELTY - The system (10) has a power performance monitoring unit (12) for monitoring, analyzing and storing power performance data of a power generation device (14). A data interface module (28) is set in power-line communication with a data acquisition module, an inverter measuring module (18) and an external network (22) for sending power performance data with a power generation module identifier (ID) and an inverter ID, of the generation device to the monitoring unit and sending a maintenance notice for requesting an maintenance action based on a specific power performance pattern.    USE - Autonomous monitoring system for power grid distributed power generation devices i.e. solar cell module, installed on a roof of a house, for autonomous monitoring, analyzing and maintaining of performance of power generation devices.    ADVANTAGE - The monitoring system maintenance can be scheduled appropriately according to the module/ inverter performance. The information on the performance of the power generation devices is communicated in real-time and autonomously available and can be generated in case of any problem of the maintenance notice to inform a provider or a user to take maintenance actions. The system represents a smart solution to manage renewable energy sources more efficiently and in real-time to maximize energy output and optimize related cost for the user and the provider. The device degradation and other fallout criteria, e.g. shadowing effects and contamination can be determined and quickly resolved. The entire data can be viewed using a web application without the need of installing additional software on a computer. The system provides a smart solution to manage renewable energy sources more efficiently and in real-time, so as to maximize energy output and optimize related costs for both user and provider.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method for autonomous maintenance of distributed power generation devices in a power grid    (2) a program product comprising a set of instructions for autonomous maintenance of distributed power generation devices in a power grid.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a monitoring system for power grid distributed power generation devices.    Autonomous monitoring system (10)    Power performance monitoring unit (12)    Power generation device (14)    Power generation module (16)    Inverter measuring module (18)    External network (22)    Data interface module (28)