Novel instrumentation for monitoring after-hours electricity consumption of electrical equipment, and some potential savings from a switch-off campaign

摘要

An increasing cause of electricity use and greenhouse gas emissions is from IT equipment such as comput-ers, printers, and servers, with worldwide computer use increasing from 1000 million PCs in 2006, to 1400 million in 2010, and estimated to cause 3% of global electricity demand. Significant energy may be saved if un-used devices are switched off. It was noted that the switch-off rates in the USA for desktop computers in 2006, could be as low as 30%, and there clearly is a need for up-to-date information. It has been difficult to provide accurate figures for switch-off rates, since previous monitoring of IT use has been expensive, requiring specialised equipment and electrical work, labour intensive (using walk-through surveys), or both. This paper demonstrates two low-cost techniques for estimation of unoccupied PC use. Precision and tracking for both were compared with actual power consumption, and subcircuit switch-off rates appeared to be under 76%. Whole building IT related use (including servers) was around 40% of elec-trical baseload. A desktop switch-off campaign was instigated for accessible equipment, resulting in a 20% reduction in electrical baseload. Extrapolation to a weeknight campaign suggests annual electricity savings of around 12%.