Loss-of-load probabilities for stand-alone photovoltaic systems

A general method is presented for estimating the loss-of-load probability (LLP) of stand-alone photovoltaic systems. The method was developed by correlating simulation results. The simulations were driven with synthetic radiation sequences having the same statistical significance as available historical data. The method assumes a constant nighttime load and accounts for the distribution and persistence in daily solar radiation data. It is shown that the 10-year average performance of systems having loss-of-load probabilities less than about .01 can vary greatly from one 10-year period to the next and thereby cannot be considered realistic performance estimates of a system during its lifetime.