[thg]

It's been around the 35% mark for at least a decade. We also import from Norway (~30%) and the Netherlands (~20%), along with about 6-8% from domestic sources and some imports from the United Kingdom.

The middle east is another potential supplier and Italy, for example, get their gas from Africa. Germany also has the biggest gas storage capacity in Europe and the gas tanks are usually filled quite well before winter (>95%). Not this year though, because the MBAs took a gamble on Nord Stream 2 going operational and lost the wager, resulting in soaring gas prices all across Europe.

You also need to keep in mind that natural gas is not solely used for heating homes, but also industrial processes and generating electricity, among others, which could be reduced or stopped if it really came down to it.

In short: Russia turning off the valves would be more of an inconvenience than the life-threatening situation it is often claimed to be. But personally I don't see that happening, as the Russians have been a very reliable supplier for decades.