Energy Use in the Media Cloud: Behaviour Change, or Technofix?

We present an analysis of the potential worldwide demand for downloaded data and the resulting energy requirements of the cloud. Assuming that the average westerner´s media consumption moves fully online but does not rise substantially beyond current levels, and the global middle class reach western levels of consumption, we estimate the overall demand to be 3200 MB/day per person, totaling 2570 Exabytes per year by the world population. We estimate the current energy demand for bandwidth to be 4 Wh/MB, based on two independent sources of data. We conclude that the average power required to support this activity would be 1175 GW at current levels of efficiency, and that a factor 60 performance improvement would be needed if infrastructure energy is to be provided by 1% of renewable energy capacity in 2030. By looking at historical trends in energy efficiency, we observe that this would be reached around 2021 if these trends continue. We document potential new applications that might require bandwidth capacity beyond our estimate. We also outline behavior change strategies that could be used to reduce the overall demand for bandwidth if historical performance improvements are not maintained, and as interim measures prior to efficiencies being realized.