What Is the Asus E-Green Utility?

E-Green disables optical drive activity if the drive has been idle for more than two minutes. According to Asus, E-Green reduces optical drive energy use by 77 percent for IDE/PATA models and 27 percent for SATA models; the disparity is simply because SATA devices are already more energy-efficient than comparable IDE devices. The E-Green program activates automatically unless the user has disabled it on the computer. According to Asus, E-Green registers information like how much power the program saved since installation and how much power an optical drive is using. While E-Green reduces energy usage, it does not increase the optical drive's lifespan. E-Green is exclusive to optical drives; there is no alternative for hard drives and other storage device types.

Optical drives typically use between 10 and 20 watts of energy when in use and drop to around 1 to 5 watts when idle. E-Green doesn't save any energy when the drive is reading or writing to a disc, but it almost negates the idle drive energy cost. According to Energy.gov, you can determine the cost of running a device by multiplying its wattage by how many hours it's used over a year and dividing by one thousand -- multiply the answer by 11 cents to get the cost-to-operate.

If you were to run an optical drive 24 hours a day for an entire year it would use approximately 88 kilowatt hours of energy. At 11 cents a kWh, the drive would cost approximately $9.63 to run. If you were to keep an optical drive on all year and use it for three hours a day, it would use about 50 kWh of energy and cost around $5.50 to run. With E-Green, that same drive would only use 19 kWh over a year and cost just $2.09 to power. The cost savings would add up to $17 over a five-year lifespan of the drive.

Like E-Green, Windows 8's Power Options system also reduces computer electricity consumption. The power plan system controls things like monitor brightness and energy use profiles that sacrifice performance for better efficiency. The Power Options also use some of the same concepts E-Green uses, as both turn off computer components if they aren't being used to save energy. The E-Green program takes priority over the Windows Power Options and improves the energy savings. You can access the power control settings by searching for "Power Options" on the Charms bar, clicking the "Settings" filter and selecting "Power Options."