If a kid lives on their own but their mom buys them groceries once per month and their dad swings by on thursdays with pizza and beer, that kid's still pretty darn self sufficient.

Similarly, if a country can use 80% less oil or imported fuel than they would have without renewable energy, I think they're pretty self-sufficient. They don't have to be isolated from trade, it's okay to import some things and export others. Energy sources can be one of those things. But if they rely on energy imports, then when something disrupts their supply then they are in trouble. However if they get 80% of their energy from renewable sources, then they have significantly less of a problem.