Information and Communication Technologies (ICTs) are responsible around 2% of worldwide greenhouse gas emissions [1]. On the other hand, the use of mobile devices (smartphone, tablet, etc.) is continually increasing. Due to the accessibility of the Internet and the cloud computing, users will use more and more software applications which will cause even an increasing effect on gas emission. Thus, an important research question is "how can we reduce or limit the energy consumption related to ICT and, in particular, related to software?" For a long time, proposed solutions focused only on the hardware design, however in recent years the software aspects have also become important. Our first objective is to compare the studies in the research area of energy efficient/green software. Relying on this survey, we will propose a methodology to measure the energy consumed by software at runtime.