Heating degree days (HDD) forecasting and heating degree days factor (HDDF) assessment in selected European countries

In this study, heating degree day (HDD), cooling degree day (CDD) and heating degree day factor (HDDF) data of seven selected countries in Europe were examined for the years between 1979 and 2022. First, HDDF values were calculated using HDD-CDD values and compared between countries. HDDF values in Finland and Norway are almost close to 1. On the other hand, HDDF values are more balanced in countries such as Greece, Spain and Italy. After this, Seasonal Autoregressive Integrated Moving Average (SARIMA) time series modeling was performed using HDD data. Before this, the data of all countries were subjected to nonparametric conditional tests for statistical validity and information about the structure of the data was obtained. Then, the parameters of the SARIMA model were determined and the model was applied. The model accuracy was assessed using criteria such as Akaike Information Criterion (AIC), Corrected Akaike Information Criterion (AICc) and Bayesian Information Criterion (BIC), and it was concluded that the modeling was weak for the Finland data, but strong for the Norway data. The results of the SARIMA model, although it has some estimation errors, especially for high-frequency fluctuations and sudden changes, generally reflect the trends of the time series correctly. In addition, the error metrics that evaluate the model accuracy generally gave satisfactory results, but the estimation errors for Finland were higher than the others.