Do I need a ID

No u dont

Yes. Count on getting carded.

Yes. After 9 they card before you walk up to the street.

Makes sense to have some form of identification in an establishment serving alcoholic beverages.

At least as of lat summer you do on weekends in the evening.

Unless something has changed, you're required to have a government-issued photo ID on you when you are inside of a bar/club venue anywhere in the state of Maryland or inside the District of Columbia. The exception is children with their parents or legal guardians. Power Plant Live is a definite yes, have an ID on you.

Yes

Yes, especially if your drinking alcohol.