An assessment of software lifecycle energy

Software energy assessment is important for reducing environmental impact of modern information technologies (IT). While software does not consume energy, for any computing hardware the energy cost of processing strongly depends on control defined by software. This paper analyzes the total energy consumption associated with software production, delivery and use and assesses their contribution to green-house gas emissions. The results reveal that the energy consumed at the production stage dominates the total lifecycle energy as software size grows. However, if software is largely used, most of the lifecycle energy is consumed at the use stage. For software as big as Linux 3.2 kernel, the total lifecycle energy exceeds 51 Giga Watt-hours i.e. equivalent of 31kilotons of CO₂ emission. Reducing this environmental impact requires energy-conscious software development and management. This paper is not intended as a comprehensive analysis rather as a starting point for research toward green software development.