Modelling Atmospheric Attenuation at Different AOD Time-scales in Yield Performance of Solar Tower Plants

Optical losses in central receiver systems may be enhanced by the atmospheric attenuation taking place along the optical path between the heliostat mirrors and the receiver. Ray-tracing and performance codes usually estimate the atmospheric attenuation by a third order polynomial whose coefficients can be input by the user in the model. A sensitivity study on the time-resolution for modelling the atmospheric attenuation is presented in this work by modelling two reference solar tower plants (Ivanpah 1 and Crescent Dunes) with the System Advisor Model (SAM). The input for the atmospheric attenuation has been computed from daily, monthly means and annual mean aerosol optical depth for the Tamanrasset site. The impact of considering one unique polynomial for the whole year to one polynomial every day is higher in the case of Crescent Dunes due to its larger solar field, and relative averages differences in the daily output power may be from around 2% to 4.5% due to the daily peaks of AOD that result in eventual high attenuating conditions for the solar field.