Analysis from the new solar radiation Atlas for Saudi Arabia

Abstract

This paper presents one of the first discussions on the new Solar Atlas of Saudi Arabia, which was launched in February 2014. It assesses selected solar resource and surface meteorological measurements available from the new Renewable Resource Atlas for Saudi Arabia developed by the King Abdullah City for Atomic and Renewable Energy (KACARE) as part of the Renewable Resource Monitoring and Mapping (RRMM) Program. The Solar Atlas provides live data recorded from 41 stations across the country. Accurate solar resource data is critical in reducing technical and financial risks of deploying utility-scale solar energy conversion systems. This paper presents solar maps of the country over time, showing that the direct normal irradiance (DNI) in various regions of the country ranges from approximately 9000Wh/m2/day in the summer months to 5000Wh/m2/day in the winter months. Global horizontal irradiance (GHI) in various regions can be as high as 8.3kWh/m2/day. One year of ground based solar radiation measurements from new stations at KACARE Headquarters Riyadh and Qassim University are compared with satellite-based model estimates of long-term DNI and GHI solar resources on a monthly mean daily total basis. Comparing the locally measured DNI data at KACARE Headquarters Riyadh with GeoModel, the average difference is about 6.9% of the reported values, the average measurement uncertainty being 8.4%. For GHI measured at KACARE Headquarters Riyadh, a fairly good agreement can be seen between the RRMM values and GeoModel with the average difference being about 5.6%, while the average measurement uncertainty being 6.7%. It might be noted that the GeoModel has data uncertainties for monthly mean daily total radiation in the range of ±8% to ±15% for DNI, and ±4% to ±8% for GHI. Finally, the paper reviews data from the recording station at Qassim University (QU), which is equipped with a variety of instruments for measuring solar radiation and surface metrological conditions. The measured values of DNI at QU varied from a maximum of 8367Wh/m2/day in July to a minimum of 4702Wh/m2/day in January. In terms of percentages, the average difference between the measured monthly mean daily total radiation and the GeoModel estimates is about 5.4% of the reported values, the average measurement uncertainty being 5.1%. In most cases, the observed differences between measured and modeled data were within the combined estimated uncertainty. The results from Solar Atlas are critical in guiding policies, reducing the risks for deploying solar facilities and providing judicious information for construction of solar facilities.