This week the graph shows hour by hour fluctuation in German energy generation from two very different energy sources, nuclear and gas. It details the production (as a percentage of daily maximum) of these generators on 7th July 2013, a day that saw record solar production and hence a great need to throttle back existing generators to ensure grid stability. As you can see from the graph, nuclear plants in fact throttled back – and then up again – more than gas turbine plants. This is remarkable, because the conventional wisdom says that nuclear plants are completely inflexible, while “flexible” gas turbines are the necessary component of renewable energy system. At least in this case, the conventional wisdom was proved completely wrong. Although the above graph shows “relative” changes, nuclear power also provided far more actual throttling (in megawatt hours) than gas plants: 100% nuclear represents the generation of 8676 MWh, while 100% gas represents 842 MWh. Sadly, the data is no longer easily or freely available, but I can provide the spreadsheet if requested.
As the graph above shows, nuclear power can and does “load-follow” as the load in the power grid fluctuates. By doing so, it helps balance out large fluctuations in the production of variable renewables. So, far from being the obstacle to renewable deployment as often claimed, nuclear power seems to be a quite critical part of it.
The claims that nuclear cannot load follow and is incompatible with renewables are mostly fiction based on outdated regulations. In France, nuclear load following is daily routine; in Germany, it became legal in 2010. It is true that nuclear plants are not run in optimum manner if they are used to load follow; for several reasons, both technical and economic, stable generation should be the goal. But load following is definitely possible and may not even be that costly: even though France even shuts down some reactors entirely for the weekends, the French enjoy one of the lowest electricity rates in Europe. And, it needs to be reminded, some of the cleanest electricity anywhere.
More on the topic of nuclear load following here: