Regional grid operators are required to send us production figures for production plants within their jurisdiction in a timely manner. We publish a monthly summary, which indicates how well the grid operators are doing their work.
You can find cumulative summaries of the way grid operators report the production figures here (in Dutch only). The summary is broken down by energy source.
Utrechtseweg 310, 6812 AR Arnhem, Postbus 718, 6800 AS Arnhem