LOL "Loss-of-load" probability (stand-alone)

This value is the probability that the user's needs cannot be met (i.e., the fraction of time when the battery is disconnected due to the "low charge" regulator protection).

It may be understood as the complement of the "Solar fraction" (although it is described in terms of time rather than energy).

During the sizing process, the LOL requirement allows for determining the PV array size needed, for a given battery capacity.

The LOL is calculated using a simplified and fast yearly simulation. The program splits the monthly weather data into a realistic random sequence of 365 days (following the Collares-Pereira model), with each day divided into 3 periods: morning, midday (with solar gains), and evening. A daily system state balance is performed to accumulate a realistic yearly LOL value.

This process is repeated with different PV array sizes to find the exact size that matches the required LOL.