Methodology to synthetically downscale DNI time series from 1-h to 1-min temporal resolution with geographic flexibility

In this paper, we present two methods for the synthetic generation of 1-min Direct Normal solar Irradiance (DNI) data from hourly means that can be applied globally without any local adaptation, which are based in the modelling of the stochastic component of DNI, and in the normalization of the daily profiles. The similitude between measured and generated DNI distributions has been evaluated through the Kolmogorov-Smirnov test Integral (KSI), and its performance on the thermal power produced by a parabolic trough (PT) plant has been assessed using the daily normalized root mean square deviations (NRMSD) with respect to site measurements. The generation methods provide, for an annual 1-min synthetic data set, KSI values of ∼3.3 W/m2 and ∼12.9 W/m2 (depending on the generation method used), and daily NRMSD of ∼0.9% and ∼3.4%, respectively. Sites selected for validating these methods are located at different climates and latitudes, suggesting their global applicability.