Wow, looks like they are being serious. I don't know the details, but I think consumer use of natural gas and energy will be small. Most will be industry.Germany's Economy & Climate Minister, Robert Habeck: "You are helping Germany, you are helping Ukraine, when you reduce your use of gas, or energy in general."
Source: DW Politics with English subtitles
In 2020, Germany burnt 171 TWh of natural gas to produce 59 TWh of electricity. The total consumption of natural gas in Germany in 2020 was 871 TWh. Values in the table are in PJ (i.e. divide by 3.6). Six nuclear reactors produced 61 TWh in the same year.
Germany (and the rest of Europe) is about to go back to the middle ages.