Operational photovoltaics power forecasting using seasonal time series ensemble

The heavy empirical evidence from the case study suggests that the ensemble forecasting using seasonal time series models only provides marginal improvements over the best component model, in the day-ahead forecasting exercise. To that end, the pitfalls of using only time series ensembles are subsequently identified and discussed. A simple remedy, namely, adding an (uncorrected) NWP model to the ensemble, is proposed. The refined ensemble results show significant improvements over the best component model, due to the expanded information set provided by the NWP model. When this additional information set is exploited, e.g., adding a model-output-statistics-corrected NWP model, further improvements on ensemble-forecast accuracy are observed. Although a theoretical discussion on the benefits of ensemble forecasting is lacking in this paper, based on the empirical study, it appears that using forecast combination is less risky than using the best component model.