Patent ID: 8369999

Claim:
A method for preventing an impending decrease in electric power supplied by a photovoltaic (PV) system connected to a power grid and by a connectable additional supplier of electric energy associated with the PV system below a limit value due to forthcoming shadowing caused by cloud formation or cloud movement, or both, comprising the steps of: analyzing the cloud formation or the cloud movement in a predetermined region between the PV system and a part of the firmament visible from the PV system, determining with a computing device, based on results of the analysis, a need for enacting a measure for maintaining a minimum of supplied power into the power grid, measuring the predetermined region with a camera, acquiring with the camera at predetermined time intervals images of the region, wherein the images are composed of a plurality of pixels, marking in the images a computed position of the sun, comparing sequential images with one another, and analyzing a change in the luminous intensity of the pixels with respect to the computed position of the sun and a location of the camera.