Sizing Handbook for Stand-Alone Photovoltaic / Storage Systems

This report details the use and development of a simplified sizing technique for stand-alone photovoltaic/storage systems. The array size and storage capacity are chosen to achieve the required loss-of-load probability (LOLP). The LOLP represents the level of confidence at which the system will satisfy the load. An LOLP of 0 means that the load will always be satisfied, and an LOLP of 1 means that the load will never be satisfied. Array sizes are read from array-sizing nomograms as a function of latitude, tilt angle, and average horizontal insolation in December (in the northern hemisphere) or June (in the southern hemisphere). Storage capacities are read from storage-sizing nomograms as a function of the required LOLP. The technique is valid for systems with a fixed tilt array, product or energy storage, and for any hourly load profile or daily load profile within a given month. The only constraint is that the average monthly load must not vary more than k 10% from month to month. The designer can choose from tilt angles from latitude minus 20° to latitude plus 20" and can choose from a range of array size/storage capacity combinations for any given LOLP.