1. A method performed using a computer, comprising: deriving a first weighted prediction using weather forecast data for a present day; deriving a second weighted prediction using present day generation data for a photovoltaic system, the present day generation data acquired by way of instrumentation coupled to the computer and to the photovoltaic system; deriving a third weighted prediction using recent historical generation data for the photovoltaic system; deriving a Bayesian model average of at least the first and the second and the third weighted predictions; and predicting a near-future generation by the photovoltaic system using the Bayesian model average.