“Green in IT” is a sub-aspect of the green IT concept, in which the goal is for IT components to be used in an environmentally compatible and resource-saving manner over their entire life cycle. This can be achieved, for instance, by optimizing the efficiency of power adapters so they consume less electricity when in operation, or by the way the software is programmed (“source code optimization”). 

According to the Smart 2020 study and the Germany Addendum, the primary fields of application for “green in IT” are:

• Computer centers
• PCs and peripherals
• Telecommunication terminal devices 
• Telecommunication networks 

In contrast to “green in IT,” methods relating to “green by IT” focus not on an IT system itself or its components and software, but rather on resource optimization achieved through the secondary effects of using IT systems, e.g. building automation or the use of smart meters.