If your sovereign territory happens to support them geographically. This is true for many, but not all countries.
Also, without large storage capacity, you might end up being self-sufficient during sunny, windy days, but find yourself very dependent on your neighbor countries for imports on overcast days or at night without wind.
The combination of all of this is especially unfortunate for hydro, where you're pretty much fully dependent on the geography you've been handed.
So I'd say the self-sufficiency story of renewables doesn't fully hold. They benefit from regional cooperation and trade just as much as fossil fuels, if not more. (In my view, that's not really a counterargument, but it does raise the importance of having a well-integrated, cross-border grid even more.)
