1. Apparatus comprising: a solar irradiance predictor processor configured to process a sequence of images, the irradiance predictor processor comprising: a cloud classifier module configured to classify respective pixels of an image of at least one cloud to indicate a solar irradiance-passing characteristic of at least a portion of said at least one cloud; a cloud motion predictor configured to predict motion of said at least one cloud over a time horizon; and an event predictor configured to predict over the time horizon occurrence of a solar obscuration event, wherein the prediction of the solar obscuration event is based on the predicted motion of said at least one cloud, wherein the event predictor includes an irradiance variation prediction for the obscuration event based on the solar irradiance-passing characteristic of said at least one cloud.