One of the marquee features of OS X 10.9 Mavericks is its energy stinginess. As Apple says, “The closer we looked, the more ways we found to increase battery efficiency.” There are a number of power-saving features in Mavericks, which you won’t see, but you can also keep your eye on which apps are using a lot of power.
If you click the battery icon in the menu bar (if you don’t see it, go to System Preferences > Energy Saver, and check Show battery status in menu bar), you’ll see if certain apps are hogging power.
It’s not clear, however, what “Significant Energy” means. I took the above screen shot when iTunes was playing iTunes Radio. I’ve tried to find other apps that use Significant Energy, and haven’t been able to. (Certain apps will always use a lot of power; for example, apps that convert or rip audio or video files.)
You can also check Activity Monitor, found it your /Applications/Utilities folder. It has a new Energy tab, which will show you real-time energy usage, along with some other useful statistics.
In any case, if you find that your laptop’s battery runs down quickly, you might want to check this menu, and Activity Monitor, from time to time to see which apps are hitting the battery the most.