Chapter 6 – Solar Resource Variability

In this chapter, we describe a methodology to quantify variability of the solar resource. We describe how the considered temporal scales, from seconds to hours, and geographical scales, from a single point to a subcontinent, are interrelated and lead to a quantifiable smoothing effect. We discuss implications of the temporal/spatial nature of solar-resource variability for the solutions needed to absorb a growing proportion of solar-generated energy on power grids. Variability is a general term that applies to many aspects of solar radiation. For example, it is used to refer to change in the solar resource from one year or one season to the next, as well as change from one site to another ( Gueymard and Wilcox 2011, Vignola 2001).