Short-Term Solar Irradiance Forecasts Using Sky Images and Radiative Transfer Model

Abstract

Abstract:In this paper, we propose a novel forecast method which addresses the difficulty in short-term solar irradiance forecasting that arises due to rapidly evolving environmental factors over short time periods. This involves the forecasting of Global Horizontal Irradiance (GHI) that combines prediction sky images with a Radiative Transfer Model (RTM). The prediction images (up to 10 min ahead) are produced by a non-local optical flow method, which is used to calculate the cloud motion for each pixel, with consecutive sky images at 1 min intervals. The Direct Normal Irradiance (DNI) and the diffuse radiation intensity field under clear sky and overcast conditions obtained from the RTM are then mapped to the sky images. Through combining the cloud locations on the prediction image with the corresponding instance of image-based DNI and diffuse radiation intensity fields, the GHI can be quantitatively forecasted for time horizons of 1-10 min ahead. The solar forecasts are evaluated in terms of root mean square error (RMSE) and mean absolute error (MAE) in relation to in-situ measurements and compared to the performance of the persistence model. The results of our experiment show that GHI forecasts using the proposed method perform better than the persistence model.

Forecast Horizon and Solar Variability Influences on the Performances of Multiscale Hybrid Forecast Model

“…In [50], spatiotemporal kriging is tested for short time horizons (from 30 s to 300 s) using the same time resolution and time horizon (Strategy 1 in this paper). For forecast techniques such as persistence, ARIMA, NN, SVM,and ML algorithms, they are tested for various time horizon different from time resolution of input data (Strategy 2) (e.g., [22,24,51,52]). In the literature, for the first time, the same forecast techniques were tested for various forecast horizons with different process strategies for the time horizon.…”

Afyonkarahisar Bölgesi Şartlarında Bulut Hareketlerinin Gökyüzü Sınıfları Tabanlı Tahmini

“…Du ve ark. ise 10 dakikalık zaman ufukları için bulut hareketi ve güneş ışınımı tahminlerini lokal olmayan bir optik akış algoritması kullanarak gerçekleştirmiştir [19].…”

The Ultra-Short-Term Forecasting of Global Horizonal Irradiance Based on Total Sky Images

“…Other studies, in which predictive cloud indices inferred from the ground-based measurements were applied to artificial neural network (ANN) or multilayer-perceptron-network (MLP) models, improved intra hour irradiance forecasting results [35,36]. The radiative transfer model was combined with predicted sky images to forecast GHI and DNI for time horizons of 1-10 min ahead [37]. Recently, minutely solar irradiance was forecasted though the mapping relationship between sky images and irradiance [38].…”