Clear-sky Irradiance Model for Real-time Sky Imager Application

Abstract

In a context of sustainable development, enthusiasm for concentrated solar power technologies is developing. So, the CSPIMP (Concentrated Solar Power efficiencyIMProvement) project started in 2013 in order toachieve a better competitiveness for the CSP plants. Its main target is to develop new procedures to improve steam turbine start up cycles, maintenance activities and plant control. One challenge in the project is to better forecast the solar resource in order to optimize plantsoperation. The development of a clear sky model is therefore an essential step to forecast Direct Normal Irradiance (DNI) becauseclear sky represents the nominal operating conditions of aconcentrating solar power plant.This paper focuses on estimating DNI under clear-sky conditionsusinga knowledge model based on the coefficient of relative optical air mass, DNI and atmospheric turbidity fluctuations. The satisfactory results obtainedvalidate the proposed methodology.