Temporal and Spatial Comparison of Gridded TMY, TDY, and TGY Data Sets

Typical Meteorological Year (TMY) data sets provide industry standard resource information for building designers and are commonly used by the solar industry to estimate photovoltaic and concentrating solar power system performance. Historically, TMY data sets were only available for certain station locations, but current TMY data sets are available on the same grid as the National Solar Radiation Database data and are referred to as the gridded TMY. In this report, a comparison of TMY, typical direct (normal irradiance) year (TDY), and typical global (horizontal irradiance) year (TGY) data sets were performed to better understand the impact of ancillary weather variables upon them. These analyses identified geographical areas of high and low temporal and spatial variability, thereby providing insight into the representativeness of a particular TMY data set for use in renewable energy as well as other applications.