I am dealing with solar power output forecasting, but I am still new to forecasting. I would like to ask a few questions here:
It seems that most literature forecasts solar irradiance, while solar power is not often directly forecasted. Why solar power times series is not of interest?
Now I have a historical data set that contains the solar power outputs from 2001 to 2012, which covers the sixth day of each month with a time resolution of 5 minutes. In this case, at which "frequency" it should be specified?
I wish to realize very-short-term forecasting. Suppose I would only use the ARIMA method. After training and testing, can I keep the obtained coefficients fixed for a typical day under study? OR they should be changed at each time interval (say, 5 minutes in this case).