Smart Power Strips
Standby power or “vampire power” is electrical power consumed from electronic
devices turned off or that are in standby mode. Studies in the United States, Brit-
ain, France, the Netherlands, Australia, and Japan show that the consumption
of electrical power due to standby power is between 7 to 13%. The U.S. Depart-
ment of Energy has stated that in the average home, 75% of the electricity used to
power home electronics is consumed while the products are turned off.
This power consumption includes devices such as printers, cell phone char-
gers, DVD players, copiers, televisions, fax machines, and so on. It tends to be
concentrated in areas such as offices and media centers. For example, the typi-
cal desk at one’s office, whether at work or at home, has a personal computer,
a monitor, probably a printer, a scanner, a VoIP telephone, a charger for a cell
phone and so on. In the past, the only management choice was to unplug the
devices, a move that may not be practical and/or safe.
Typically these devices are fed by a power strip with some surge protection.
Current power strips have gotten smarter by incorporating microprocessors,
thus allowing the strip to sense the electrical current and to monitor and man-
age the plug load. Some outlets on the power strip may be able to turn devices
on or off by sensing whether the device is in use or in a prolonged idle state.
The outlets can be turned off within a user-defined set time after the device
goes idle. Other power strips are triggered by the personal computer; that is,
the personal computer is plugged into a “control plug” on the strip and the
power strip will shut down the peripheral devices when the personal computer
is shut down.
Smart power strips can incorporate meters to provide information to users
regarding energy consumption. Some go as far as providing energy costs and
power quality, including voltage, line frequency, and power factor.
Smart power strips have also moved into data centers where rack-mounted
strips feed servers, network switches, and other equipment. These power strips
have an IP Ethernet port allowing managers to monitor, manage and reboot
equipment intelligently.
POE
POE devices can be telephones, wireless access points, cameras, paging speak-
ers, card readers and so on. Several major IT manufacturers have developed
software to manage power to the devices, either turning them off and on or
dimming the power to these devices, much like a lighting control system.
The power-over-Ethernet management software essentially enables and dis-
ables ports on a network switch. The result is a reduction in peak energy
Electric Power Management Systems 67