[5] This constitutes about 1.5% of total US electricity consumption[6] Significant opportunities exist for Enterprises to optimise their IT energy usage.
30% of this electricity goes to power terminal equipment (computers, mobiles and other devices), 30% goes to data centers and 40% goes to the network.
This is typically done by doing diagnostic tests on individual servers and developing a model for a data center's energy demand using these measurements.
User behaviour is slightly different in Europe, with approximately 28% of PCs being left on overnight in the UK, resulting in an estimated energy loss of 2.5 billion kWh, costing £300 million per year.
In Germany, with approximately 30% of PCs left on overnight, it is estimated 4.8 billion kWh of energy are wasted each year, costing €919 million[12] There is a significant market in third-party Power Management Software offering features beyond those present in the Windows operating system.
In 2005, all the network-interface controllers in the United States (in computers, switches, and routers) used an estimated 5.3 terawatt-hours of electricity.