Organisations that are actively employing power management functionality can expect to save $43 300.00 per year, compared with an unmanaged 2 500-PC organisation.

In addition, says Gartner, turning off and unplugging machines saves another $6 500.00, but this may affect employee productivity because updates will need to be carried out during working hours.
"Much attention on power consumption has focused on the data centre, but PC power consumption in an organisation can also be significant, especially given steadily rising electricity prices," says Federica Troni, principal analyst at Gartner. "IT organisations should recognise that the greatest savings come from employing power management features. They should investigate the power management capabilities of their PC lifecycle management tools and PC power management point solutions to implement these policies and to better support management activities."
Gartner has created a model to assess the impact of different variables on an organisation¹s total PC power use that calculates the power consumption for desktops, notebooks and associated monitors during the workday and after hours.
The model is based on three different scenarios – the well-managed, unmanaged and unplugged organisation – and includes a number of common assumptions, including: there are 2s500 employees in the organisation, the ratio of PCs to employees is one-to-one, employees work an eight-hour business day 230 days per year and active use of the PC during working hours is 70% of the time. The power calculation assumes a cost of $0,1 for one kilowatt-hour (kWh).
"Although we concentrated on three specific scenarios, the model can be used to assess the PC-related power consumption in any organisation," says Charles Smulders, managing vice-president at Gartner. "In addition, the results of the assessment can be adjusted to reflect only the power used and paid for by the organisation, thus excluding the power consumed by a mobile PC that is being used off the organisation¹s premises."
In the well-managed scenario, it is assumed that power management features are activated on all devices, and desktops are not switched off or unplugged after hours, thereby enabling remote updates to be performed. Notebook devices are switched off or placed in suspend mode 50% of the time after hours and of these, 50% are unplugged after hours.
In the unmanaged scenario, no attempt is made to manage or control the power management features, and users are left to decide whether to activate or deactivate the power management features. In this scenario it is assumed that both desktop and notebook users activate power management features in 50% of the cases, 50% of desktops are switched off after hours and notebook devices are switched off or placed in suspend mode 50% of the time after hours, and of these, 50% are unplugged after hours.
In the unplugged scenario, all PC devices are unplugged when not in use after hours.
The annual cost savings associated with a well-managed environment versus an unmanaged one is $43 300.00. This assumes that all power is paid for by the organisation. Excluding the power consumed when mobile PCs are used off the organisation¹s premises, the annual cost saving is calculated to be $27 500.00.
"Undoubtedly, with proper policies in place, substantial power and cost savings can be achieved without an impact on user productivity," says Troni. "Unplugging machines brings further reductions in power and additional cost savings, compared with a well-managed environment; however, we believe that implementing such policies is impractical, and is likely to obstruct productivity because updates can¹t easily be performed after hours."