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 & Privacy

• disable remote control infrared receiver

Menubar

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