Performance royalties are generated when a song is "publicly broadcast" such as on radio, television, in restaurants/bars/nightclubs, live, etc. Performance royalties are also generated when your song is sung or played live and when it is played on certain forms of digital media like internet radio.
When you write a song, one of your exclusive rights as the copyright holder is the right to perform your composition in public.
If someone wants to use your composition for commercial use, they require a license to do so. Obviously, it's not possible for every TV / radio station, restaurant, live venue, jukebox, etc. to contact you for each use of your song. Instead, these businesses pay blanket licenses to Performing Rights Organizations (PROs), who then redistribute those license fees to their member songwriters.
Songtrust can affiliate you with a PRO and will ensure that your songs are professionally registered for the collection of performance royalties.
The diagram below helps break down the flow of performance royalties