Since version 2.6.21, the Linux kernel has introduced a feature called tickless. the kernel no longer has a fixed 1000Hz timer tick. This will give a dramatic power savings because the CPU stays in low power mode for longer periods of time during system idle.A Nice handy tool, PowerTop has been created for reducing the Power Usage of Linux. This application will help to find the software components that are preventing optimal usage of your hardware and give proper suggestions for both hardware and software configurations to reduce power consumption of your system. So Now Your Ubuntu is energy Efficient.It is very useful for Laptop Users.
How To Install PowerTop in Ubuntu
Open a terminal and type the following
$ sudo apt-get install powertop
Or You can use Synaptic Package manager and select package powertop.