Are there no explicit Power modes in Mac?
There are no build-in power modes in Mac OS X. Still, the standard configuration in Mac OS X in combination with the high capacity batteries used in the MacBooks offers quite good battery life.

If you want to optimize your energy usage, you need to manually tweak settings.

Here's, what OS X offers to save power:

System Settings -> Energy Saver


dim display when using battery
display/computer sleep


System Settings -> Display


Automatically adjust brightness


System Settings -> Security &amp; Privacy


disable remote control infrared receiver


Menubar


Wifi Icon -> disable Wifi
Bluetooth icon -> disable Bluetooth