[patrickk]

This excludes connecting further to Germany’s neighbours, e.g. using Norway’s hydro exports as a battery.

https://en.m.wikipedia.org/wiki/European_super_grid

Ireland and Britain has massive offshore wind potential that is only being slowly ramped up, for example. Macron has announced a new nuclear reactor building program, so potentially more carbon-free electricity to nuclear-adverse Germany. The massive Danish offshore wind park/energy island has yet to come online but will supply northern Germany.

And if you want to go even more exotic, you could get 24/7/365 renewable energy by piping geothermal to continental Europe from Iceland which has an oversupply. Or even building enormous solar parks in the Sahara (geopolitical risks notwithstanding).

There are plenty of options enabled by geographic distribution of supply without even looking at storage. The main problem is the lack of political will until now, which is changing with the realisation in Germany that Russia isn’t a reliable partner.

Edit: none of these rely on any technical breakthroughs either, merely ramping up the interconnection of grids and renewable sources of electricity.