Integration of ground measurements to model- derived data : A report of IEA SHC Task 46 Solar Resource Assessment and Forecasting

Bankable data for solar energy projects needs to ensure as much as possible the accuracy and general quality of solar radiation data to be used in the solar resource assessment studies for any site of interest in a project development. The term “site adaptation” is being used in the framework of solar energy projects to refer to the improvement that can be achieved in satellite-derived (or more generally model-derived) solar irradiance when short-term local ground measurements are used to correct systematic errors and bias of the original dataset. This document presents a review of different techniques for correcting long-term satellite- derived solar radiation data by using short-term ground measurements. The collaborative work has been done within the framework of Task 46 “Solar Resource Assessment and Forecasting” of the International Energy Agency's Solar Heating and Cooling Programme. Different approaches whose use depends on the origin and characteristics of the uncertainties of the modelled data are presented. Recommendations to the use of ground measurements and the results of several approaches to improve satellite-derived data are shown through this report highlighting the importance of using site adaptation and the different degree of improvement that can be achieved depending on the climatological characteristics of the site