The National Climate Database (NCDB) Version 1: Development, Evaluation, and Data Release

Solar PV power is expected to play a key role in the energy transition needed to reduce the use of fossil fuels and mitigate climate change. However, a sustainable energy transition necessitates accurate planning to account for anticipated changes in climate regimes throughout the full lifespan of PV power systems. Given that a changing climate enhances the weather variability and extremes impacting PV, it is essential to analyze and understand potential impacts of climate change on solar generation under future climate scenarios. To support the climate-related energy applications, the National Renewable Energy Laboratory has developed the National Climate Database (NCDB, https://climate.nrel.gov/) that aims to provide users high-resolution climate datasets. The NCDB Version 1 is focused on creating high-resolution, unbiased future projections of solar irradiance using a statistical downscaling approach with a climate projection dataset simulated by the Regional Climate Model (RCM) obtained from the North American Coordinated Regional Climate Downscaling Experiment (NA-CORDEX). In addition, the National Solar Radiation Database (NSRDB) is used to calibrate the statistical downscaling models. Currently, the NCDB serves 4-km hourly dataset that includes solar irradiance, air temperature, and surface wind speed over the contiguous United States (CONUS) under two climate scenarios (RCP4.5 and RCP8.5). This study will present main research steps in developing the NCDB Version 1 including (1) regridding RCM data to a common grid at 20-km resolution, (2) correcting the bias of RCM projections using the NSRDB, (3) implementing the temporal and spatial downscaling techniques to generate climate projections at 4-km and hourly resolution. This presentation will summarize evaluation results of the downscaled climate data against NSRDB across different climate zones for the entire CONUS. Moreover, we will introduce the user’s guide for NCDB data download/viewer and future extension of this research.