If you're roleplaying in a non-conflict situation, and a use of power comes up, does that incur debt?
No.
If you aren't using it per the rules, it doesn't cost Debt.
I'm having trouble replying to this, because you're using this funny phrase "roleplaying in a non-conflict situation" which I can't quite parse into Capes parlance. Can you give an example, with special reference to what rules were active at the time?
Okay...
To make it simple...
We're in the "scene setting" phase. No conflicts are on the table.
I say, "Kozmik Ray is working out in the team's exercise room. He's bench-pressing an M-1 tank."
Clearly, Kozmik Ray is using his power... but it's not part of a conflict. It's a casual, off the cuff mention. Pure color.
Doesn't cost you anything.
Also, if you use your "Angry" Ability, and describe angrily ripping a titanium bar to shreds, no Debt is accrued off your super-strength.