If the numbers I’ve heard are correct, storage at capacity will only account for about 12% of typical German consumption over the winter. Frankly that number seems high to me, but then again I’ve never lived in a country which has to import gas.
There are two complicated parts to the story.
First, do you have a normal-moderate winter, or a severe winter? Last year, I would describe as fairly moderate.
Second, there are two ways that the use of natural gas figures the consumption. Roughly half of homes/apartments use natural gas for heat. Around 10-to-12 percent of the national grid consumes natural to produce power (backing-up solar and wind). If you lessen the grid situation (by using coal/nuke power longer), then you would save on use of gas for power production.
None of this big picture discussion is really understood by the political establishment.