This is not true. The agreement between the federal government and the energy supply companies to phase out nuclear energy dates back to 14 June 2000. The first nuclear power plant was shut down permanently in Nov. 2003. At this time the power generation from coal (both hard coal and lignite) was around 300 TWh/year. It almost halfed to 162.6 TWh in 2021. The all time low was in 2020, though, due to the pandemic.
Coal has only increased in 2021, but fossil fuels have increased since 2002 (from 69.9GW to 78.9GW), i misremembered that statistic as coal instead of fossil fuels
The consumption of natural gas itself has indeed increased. But the sum of natural gas + coal has still decreased a lot. From aprox. 350 TWh per year in the early 2000s to 251,6 TWh in 2021. The partial replacement of coal by natural gas is at least in part caused by the transition to renewable energies. Until the transition is complete, natural gas is the best fossil fuel option to even out fluctuations in the production of renewable energy, because gas power plants can be switched on and off very quickly at peak times (in strong contrast btw to nuclear power plants) and they can be built relatively decentralized, each with a small volume. Therefore it is not likely that we will see a major drop in natural gas consumption in Germany in the next two decades.
> gas power plants can be switched on and off very quickly at peak times (in strong contrast btw to nuclear power plants)
Not true - from the wiki: Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope, up to 140 MW/minute. Nuclear power plants in France and in Germany operate in load-following mode and so participate in the primary and secondary frequency control.
A nuclear reactor can only do this (depending upon combustible bars state) at most twice per day. This is a severe limitation.
France is a leader in this field.
Source (French language ahead!):
https://new.sfen.org/rgn/expertise-nucleaire-francaise-suivi...
Gas plants have a possible rate of change of aprox. 20%/minute. Admittedly, it may be a matter of taste whether a fourfold rate might be called a "strong" contrast. So let's just say that the rate of change of gas plants is typically four times higher.
Besides, the actual rates of change for nuclear power plants vary widely, depending on the current load of the power plant. According to the German Wikipedia the actual capabilities of (former) nuclear power plants in Germany ranged from 1.1% to 10% per minute. When the plant was below 50% of its load, the possible rate was near the lower end of this spectrum. The maximum of 10% was only possible when the plant was already running above of 80% of their nominal power. The value was also very much dependent on the operating state of the plant.[1] So the 5%/minute you mentioned are just an average.
Historically, nuclear power plants have been used as load following plants in Germany, but this was during times, when the overall volatility of power production was lower than today. And when it comes to new nuclear power plants currently being planned elsewhere, their load following capabilities are to my knowledge typically an afterthought.
For details of Germany's energy production and consumption since 1990 see: https://www.cleanenergywire.org/factsheets/germanys-energy-c...