This paper summarizes and analyzes recent research by the authors and others to understand, characterize, and model solar resource variability. This research shows that understanding solar energy variability requires a definition of the temporal and spatial context for which variability is assessed; and describes a predictable, quantifiable variability-smoothing space-time continuum from a single point to thousands of kilometers and from seconds to days. Implications for solar penetration on the power grid and variability mitigation strategies are discussed.
