Patent US 8,335,649

A computer-implemented system and method for estimating photovoltaic power generation for use in photovoltaic fleet operation is provided. A set of sky clearness indexes is generated as a ratio of each irradiance observation in a set of irradiance observations that has been regularly measured for a plurality of locations, which are each within a geographic region suitable for operation of a photovoltaic fleet, and clear sky irradiance. A time series of the set of the sky clearness indexes is formed for all of the locations within the geographic region. Fleet irradiance statistics for the photovoltaic fleet are generated through statistical evaluation of the time series of the set of the sky clearness indexes. Power statistics for the photovoltaic fleet are built as a function of the fleet irradiance statistics and an overall power rating of the photovoltaic fleet.