> Frequency controlling a grid (e.g. increasing or decreasing plant output by a few %s) is important for grid stability first and foremost. Grid costs are less

> Frequency controlling a grid (e.g. increasing or decreasing plant output by a few %s) is important for grid stability first and foremost. Grid costs are less important > redundancy reasons and ease of implementation, this flexibility is split between as many plants as possible for each operator. This is the core of the argument. My point is that if the nuclear fleet was flexible enough to provide 100% of the follow-up it would do so (because it emits less and costs less), and therefore production snapshots would rarely show significant production from flamme plants (burning fossil fuel), which would only be significant during peak consumption. In other words thanks to such a sufficient flexibility the merit-order could be sound at any moment. The reality is that those 'fossil' plants very often (nearly constantly) generate a fair fraction of the gridpower (they aren't in minimal production "ready to warm-start" mode, they generate in a useful way). > The step at which you can prioritize less costly means of production is scheduled ahead of time. This is when you typically need larger variations, such as moving a plant's output from 100% to 20%. In this step, merit order is used, and, to my knowledge, nuclear has priority over gas in France. Yes, and it shows that the nuclear fleet can always (bar any incident) tackle a rather large scheduled (in hours) modulation, which is a totally different challenge than "realtime" follow-up.