well.. its actually a bit more complex than that. The TLDR is that the slack of nuclear was picked up by renewables (mostly wind). the slightly more complicated reason is that wind often was kept off in favor of non-throttle-able base-loads like coal and nuclear. Now with the latter out of the picture the slack has to be taken up my either expensive NGAS or wind. NGAS can be throttled somewhat quickly so if there is wind its now used.

This suddenly reveals the true capacities that were there all along.