In this paper we present a decision support system for mitigation of PV plant failures to be used in a platform supporting operation and maintenance (O&M) operators in taking the most cost-effective decision in case of performance loss. Within the Solar Bankability project risk assessment and risk management were studied. Several real maintenance tickets were collected and analyzed for typical failures during the lifetime of PV plants in order to develop a technical risk framework and to determine mitigation measures able to minimize the risk for project investments. Besides preventive and corrective mitigation measures applied before the failure happens or implemented during the operation and maintenance phase, this work introduces also direct mitigation options which can be applied in already running plants. Within PV4.0 the aim is to improve further failure data collection and to develop a fully automated decision support system that calculates the economic impact of failures and suggests a list of possible intervention strategies. The Cost Priority Number (CPN) methodology is in the core center of the PV4.0 tool since it prioritizes O&M interventions according to the economic impact of the technical risks helping so in the decision process.