Performance analysis of stand alone PV systems from a rational use of energy point of view

The performance analysis of stand alone PV systems (SAS) is not as straight forward as it is for grid connected systems. A poor performance does not mean that the system encounters technical problems but can also be the consequence of a bad matching between the production and the load. Some coefficients have already been introduced within IEA PVPS task 2 to consider poor sizing and technical problems by complementing the performance ratio. This paper presents, through examples, different cases where the commonly used factors show their limits and highlight how some new coefficients, can better inform on the operational performance of stand alone systems.