Ever wondered how much the weight of 10,000 open browser tabs is dragging down your laptop's battery? Fear not: AnandTech just dug into the particulars with a delightfully detailed test to find out which browser is the biggest battery hog. This information could save mankind('s laptop batteries).
You really should go read the entire test over at AnandTech-it
gives a great, in-depth look at how different browsers work, how
different settings affect page-loading speeds, and more. But here's the
bottom line: the number of minutes each browser cruised along before the
laptop's battery drained to 7 percent: 
Of course, your exact battery mileage may vary: AnandTech used a Dell XPS 15 laptop with a high-res display, and the actual number of minutes will no doubt vary between manufacturers and OSes. But proportionally, this gives a good idea of how Chrome (both the current stable build and the beta), two versions of Explorer, and the latest Firefox stack up.