How to track energy consumption

The app I'm working on is pretty simple. It simply stores, organized, and plays videos added to it's library. The interface is a table view with the name, size, and date of creation of the videos. Each cell in the table view also has a thumbnail image of the video which is generated on app startup. There is nav and tab controller which allows the user to go the trash and settings. It's not graphics heavy at all from what I can see in my code. However, my debugger is telling me that I'm using a lot of power and that all of it is from the display. I'm testing this with my iPhone Xs. Can someone please point me in the direction I need to look?