WRF-Solar to Advance Solar Power Forecasting

The WRF-Solar is the WRF model augmented with new capability aimed at improving model components central to solar power forecasting, and providing relevant solar parameters to decision-makers. Model physics packages upgraded for solar energy applications will be presented. Developments focus on three primary areas. 1) Improvements in the shortwave radiation parameterization to correct for irregularities in the natural length of the day (equation of time), allow clear-sky radiation to interact with aerosols, and output high frequency direct and diffuse components. 2) The microphysics parameterization was upgraded to include ambient water- and ice-nucleation aerosols as well as to improve consistency between cloud particles and radiation. 3) The shallow convection parameterization was improved to connect sub-grid fractional clouds to radiation schemes. These model developments were assessed against high frequency observations of the shortwave radiation components over the contiguous US. WRF-solar will be run operationally starting at the end of the present year as part of a solar power forecasting system that blends different forecasting methodologies. The system will be tested in several high penetration solar utilities and ISOs with geographic and climatological diversity. The performance of WRF-solar as part of this forecasting system will be examined.