At one point, the main sources of manageable IT energy demand were PCs and Monitors, accounting for 39% of energy use, followed by data centers and servers, accounting for 23% of energy use.[4] In 2006, US IT infrastructures consumed an estimated 61 billion kWh of energy, totaling to a cost of $4.5 billion.[5] Significant opportunities exist for Enterprises to optimise their IT energy usage.[6] Computers, data centers and networks consume 10% of the world’s electricity.