EXECUTIVE SUMMARY

The amount of electricity used by servers and other Internet infrastructure has become an important issue in recent years as demands for new Internet services (like music downloads, video-on-demand, and Internet telephony) have become more widespread. One of the weaknesses in the literature on data center electricity use has been the lack of credible estimates of the aggregate power used by all servers and associated equipment in the U.S. and the world. The data on the floor area and power densities of data centers are anecdotal and limited by the proprietary nature of such data in most companies. Data on the installed base of servers are also closely held by the companies who track it, and server technology continues to change rapidly, necessitating constant updates to measurements of power used by particular server models. This study estimates total electricity used by servers in the U.S. and the world by combining measured data and estimates of power used by the most popular servers with data on the server installed base. These estimates are based on more detailed data than are previous assessments, and they will be of use to policy makers and businesses attempting to make sense of recent trends in this industry