We all know that one of the biggest problems with equipments that work with batteries is the need to charge them usually more often that we would like to do it, this applies to smartphones and laptops.
The problem is more or less the same with them both, and it is the display, in the case of laptops the more powerful your graphics card is, the faster you'll need to recharge your laptop's battery.
We also know that we do not need all that power all the time, we may need it if we are using our laptop to play games, but for normal uses, like surfing the web, reading emails or creating a document.
Nvidia has come with a great feature the "Nvidia optimus technology".
Nvidia optimus Technology
Optimus technology is completely automatic allowing you to experience longer battery life and amazing visuals without having to manually change settings. Behind the scenes and with no interference to what you're doing, Optimus seamlessly figures out how to best optimize your notebook computing experience. NVIDIA graphics you've come to expect, with more than 10x better performance¹ with NVIDIA® CUDA™ technology, allowing you to enjoy your applications and games without interruption or worry.
This is not completely true with Linux, where you will need to adjust manually how much power your card will give you, but anyway, it will save battery juice.
bumblebee is Optimus support for Linux, with real offloading, and not switchable graphics.. More important.. it works on Optimus Laptops without a graphical multiplexer..
You can install it on Ubuntu using this PPA:
You may also read how to install it and configure it at Arch Linux Wiki
And you will find the project at GitHub