As you complete daily POWER Bounties, you will collect Fragments to acquire POWER Energy and fill up the Energy Meter. There are two kinds of Fragments you can get: 

Regular Fragments 

You obtain Regular Fragments (or just Fragments) from completing Free Bounties. As you accumulate them, you can exchange them for POWER Energy to fill up the Energy Meter (and increase your Reward Level!).

Premium Fragments

To speed up your progress and fill up your Energy Meter more quickly, you can buy Premium Fragments from the Ronin Store using $POWER [ LINK ]. These fragments give you access to Premium Bounties, which offer better rewards than Free Bounties. However, you'll need to spend some of your Premium Fragments to claim these rewards.