ZMA Center Controller reported the Grand Turk Radar went out from a power outage and due to ATC's inability to communicate with the aircraft; led to separation problems. Reporter also stated this is a recurring problem.

Narrative

The Grand Turk Radar went out without warning. Due to this event being unscheduled none of the aircraft in the sector were separated by routes for a non radar environment. Aircraft X and Aircraft Y were separated with radar but not by route or 10 minutes for a non radar situation. My D-Side and I started working to ensure separation for multiple aircraft with the unfolding situation; including coordinating with New York about altitude changes. While this was taking place the frequency for my sector; adjacent sector; and Guard also went out so there was no way to talk to aircraft. It was later found out that the electricity on the island went out and there was an issue with the backup generators.This continues to be a safety issue that is recurring. I recommend finding a way to provide consistent power to our radar and frequencies. There have also been multiple instances where power issues have not been communicated from the island and caught us off guard. If we could work out a way to be told when planned outages are occurring on a consistent basis; this would also be a great help.