Checking to see what apps are taking up the most energy on your MacBook is actually quite easy, the process just isn't that obvious.
The Simple Way
The simplest way to check is to see a stripped-back version of what's using battery by clicking on the battery icon up in the menu bar. This will show a pop-up that will show you 'Apps Using Significant Energy'. These apps are deemed by your MacBook to be hogging more of your resources than what is necessary.
Use Activity Monitor
To get more of an in-depth view of where your battery power is going, all you have to do is check with Activity Monitor. Open it from your apps and select the CPU tab. Sort the apps by CPU % if they're not already.
This will then tell you what apps are using the most battery, if you notice there is a particular one using more battery than what you think is necessary, just hit the stop button at the top of the window or close the app.