The predicted annual growth of energy consumption in ICT by 4% towards 2020, despite improvements and efficiency gains in technology, is challenging our ability to claim that ICT is providing overall gains in energy efficiency and Carbon Imprint as computers and networks are increasingly used in all sectors of activity. Thus we must find means to limit this increase and preserve quality of service (QoS) in computer systems and networks. Since the energy consumed in ICT is related to system load, ]this paper discusses the choice of system load that offers the best trade-off between energy consumption and QoS. We use both simple queueing models and measurements to develop and illustrate the results. A discussion is also provided regarding future research directions. Keywords: Energy Consumption, Quality of Service, Optimisation, Computer Systems CO 2 emissions due to energy consumption by ICT by 2020 is expected to exceed 1.4 Billion Tonnes. Thus it is particularly important to achieve energy savings in the ICT sector whose annual increase in electricity consumption is of the order of 4%, despite the significant improvements in the efficiency of hardware technologies that are being achieved year after year. Such issues are relevant both for communication systems such as base stations for mobile phones, and routers in networks, as well as for personal computers, office servers, and for large data centres. Indeed, by 2020 telecommunication systems are predicted to consume some 25% of the energy that is used in ICT systems, while data centres will account for some 18% of the total, and the rest will be caused by personal devices, office computers and servers. The increasing importance of the Internet and the great interest in reducing energy consumption in all areas of human activity, increase the importance of making computer
Gelenbe et al. REF has proposed the relationship and effect between choice of system load, energy consumption and QoS using a simple queuing model.
Optimising server energy consumption and response time
Theoretical and Applied Informatics
Computer Science