Tracking movement of clouds is used to predict the effects of cloud cover on irradiation of a solar-powered distributed power generation system. The predictions enable a solar power plant to maintain the changes in its total power output within operating requirements with less or no dependence on energy storage, back up generation, or load control, use centralized and/or local coordination of solar farm control systems to use storage to its best advantage, alternately reduce power fluctuations without cloud knowledge and use real time solar output prediction capabilities to be able to provide utilities with advance information regarding power fluctuations.