Nothing generates more than nuclear (like it's not even comparable), it has basically zero emissions and there are countries like Finland who'll happily let you burry it there, tho you ofc don't need to go that far away. You don't need to dispose it nearly as often as coal ash, so it being in another country ain't really that big of a deal.

Ofc solar is also a great option, because of the versatility, sadly German seems to really fucking love wind.