Powertop : [Top + Power Management]

Powertop is a utility software that lists processes which are eating away your battery power & suggests you power saving useful tips. The utility in mainly meant for laptops where power consumption is critical issue. Powertop is the project of lesswatts.org. You can check this link for the processes which usually consume more power.


Quoting from lesswatts.org

As of Linux kernel version 2.6.21, the kernel no longer has a fixed 1000Hz timer tick. This will (in theory) give a huge power savings because the CPU stays in low power mode for longer periods of time during system idle. PowerTOP combines various sources of information from the kernel into one convenient screen so that you can see how well your system is doing, and which components are the biggest problem.

As stated in lesswatts.org site, PowerTOP has these four basic goals:

• Show how well your system is using the various hardware power-saving features
• Show you the culprit software components that are preventing optimal usage of your hardware power savings
• Help Linux developers test their application and achieve optimal behavior
• Provide you with tuning suggestions to achieve low power consumption 

 PowerTop covers all major linux distros, run PowerTop by typing powertop. It will show you ACPI estimate of power consumption & lists you suggestions if some process is unnecessarily wasting power.

Requirements:
32 bit :kernel 2.6.21 or later
64 bit :expected in kernel 2.6.23

Before installing have a look at the faq of powertop.
Download link.

References:
http://www.lesswatts.org/projects/powertop/
http://www.serverwatch.com/tutorials/article.php/3916986/Using-Powertop-to-Lower-System-Power-Usage.htm