Uncertainty Model for Total Solar Irradiance Estimation on Australian Rooftops

Hassan Al-Saadi,Said Al-Sarawi,Rastko Zivanovic,W.E Alnaser,A.A Sayigh

doi:10.1051/e3sconf/20172301004

Abstract

The installations of solar panels on Australian rooftops have been in rise for the last few years, especially in the urban areas. This motivates academic researchers, distribution network operators and engineers to accurately address the level of uncertainty resulting from grid-connected solar panels. The main source of uncertainty is the intermittent nature of radiation, therefore, this paper presents a new model to estimate the total radiation incident on a tilted solar panel. Where a probability distribution factorizes clearness index, the model is driven upon clearness index with special attention being paid for Australia with the utilization of best-fit-correlation for diffuse fraction. The assessment of the model validity is achieved with the adoption of four goodness-of-fit techniques. In addition, the Quasi Monte Carlo and sparse grid methods are used as sampling and uncertainty computation tools, respectively. High resolution data resolution of solar irradiations for Adelaide city were used for this assessment, with an outcome indicating a satisfactory agreement between actual data variation and model.

Highlights

The current prevalence of solar rooftops in Australia incentivizes academic researchers, engineers and power network operators to investigate in detail solar engineering applications
This paper presents a new uncertainty model for the estimation of total solar radiation reaching Australian rooftops
The uncertainty is characterized by the probability density function (PDF) of clearness index when the diffuse fraction is functionally correlated through the utilization of logistic relation

Summary

Introduction

The current prevalence of solar rooftops in Australia incentivizes academic researchers, engineers and power network operators to investigate in detail solar engineering applications. A new model for uncertainty prediction of solar irradiation incident on a tilted surface is presented Where such model is yet to be satisfactorily modelled, this model is built upon a given characterization of clearness index and diffuse fraction of radiation while taking into consideration the Australian climate conditions. Solar Variation For the variations of solar radiation, two vital factors have been identified to be representing the clearness of the sky: clearness index, kktt, and diffuse fraction, kkdd These quantities are highly correlated with different functions established on the subject, such as piecewise linear [2], piecewise 4th-order polynomial [5], piecewise 3rd-order polynomial [6], piecewise 2nd-order polynomial [7], logistic [8]. The subscript ii denotes the ii-th value of an hourly solar irradiation; nn is the number of the hours from different days in a month across involved years

Mean bias error

Day time RMSE

Conclusion