A global perspective on energy conservation in large data networks

As much as 8-10% of the global energy supply goes toward powering the global telecommunications network and the 19 billion electronic devices interconnected by it (ICT). If unabated, ICT energy needs will likely rise higher with even more networked devices in the future: a billion more added within the first half of 2014. While there are many endeavors focused on individual low-power devices, few are examining broad strategies that cross the many boundaries of separate concerns and technologies involved, and perhaps even fewer are projecting these analyses forward five to ten years to examine the effects of exponential growth and of technologies improving at different rates. This work aims to provide a broader view of the potential energy savings from new technologies and techniques-broader both in the scale and temporal range considered. It analyses several strategies for saving energy, assessing a local and global energy efficiency and a carbon footprint associated with their use within ICT. One finding is that there is a significant net gain from expending processing effort to lower information entropy: on the order of 52-73% net reduction in energy consumption over uncompressed transmissions. Choosing the most energy-efficient method of the methods tested in each year, results also suggest that processing energy´s share of total energy will increase from 4.9%-17.6% in the timespan from 2013 to 2025, with communication energy still dominating but diminishing in importance. Another finding is that, for a single, common, and resource-intensive use such as streaming video to residences during nightly television-watching, the most energy-efficient method of those tested results in 15.4TJ reduction in annual global energy use-saving the output of roughly two power plants, and along with it reducing CO₂ emissions 69K-12.4M tonnes annually.