Not really unless you are earning crowns that you plan on spending on energy. You have to try dying less, or if you do, let a party member revive you instead of spending the energy yourself. There is an indicator under the minimap that tells you how difficult a dungeon is for you. I hope this helps.
^ To explore the clockworks, i.e. play the game. Every time you go down a new floor, you lose 10 energy.
The bottom bar is your Mist energy, which caps out at 100. You restore 1 mist energy every 15 minutes(?) or so. The number count above it your Crystal energy. Crystal energy has no cap, and is stored until you use it. You can either trade for it with Crowns (in-game money) or buy some using real money.
Forgot to mention, energy is also used for crafting, and opening special doors inside the dungeons.
To get more energy, click on the main menu button and "Purchase energy" is at the bottom. The page it puts you on is the one to buy it with cash, but there are three tabs, one for cash, one for the instant market which gives you the best immediately available offer, and the market tab where you can set up a buy order, which is your best bet for cost if you can wait a minute or two to get your energy.
Energy tends to cost more on the weekend when there's a lot of people playing, and the price tends to go down midweek when fewer people are playing.
Prancin' aboot with me head full of eyeballs since '07 My Spore stuff: http://www.spore.com/view/profile/Errick