Standby power

For systems that provide auxiliary power, see Emergency power system.

"Phantom load" redirects here. For microphone powering technique, see Phantom power.

Standby power, also called vampire power, phantom load, or leaking electricity, refers to the electric power consumed by electronic appliances while they are switched off or in a standby mode. A very common "electricity vampire" is a power adapter which has no power-off switch. Some such devices offer remote controls and digital clock features to the user, while other devices, such as power adapters for laptop computers and other electronic devices, consume power without offering any features.

Consequences

The wasted standby power of household electronic devices is typically very small, but the sum of all such devices within the household becomes significant. Standby power makes up a portion of homes' steadily rising miscellaneous electric load, which also includes small appliances, security systems, and other small power draws.

Standby power is typically 10 to 15 watts per device, and occasionally more. A 2005 study estimates the number of standby appliances in the EU at 3.7 billion. Although the power needed for functions like displays, indicators, and remote control functions is relatively small, the fact that the devices are continuously plugged in, and the number of such devices in the average household means that the energy usage can reach up to 22 percent of all appliance consumption, and around 10 percent of total residential consumption.

Alan Meier, a staff scientist at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, noted that many household appliances are never fully switched off, but spend most of the time in a standby mode. His 1998 study estimated that standby power consumption accounted for approximately 5% of total residential electricity consumption in America, “adding up to more than $3 billion in annual energy costs”. According to America's Department of Energy, national residential electricity consumption in 2004 was 1.29 billion megawatt hours (MWh)—5% of which is 64m MWh. The wasted energy, in other words, is equivalent to the output of 18 typical power stations. His 2000 study showed that standby power accounted for around 10% of household power-consumption.

The British Government's 2006 Energy Review found that standby modes on electronic devices account for 8% of all British domestic power consumption. A similar study in France in 2000 found that standby power accounted for 7% of total residential consumption. Further studies have since come to similar conclusions in other developed countries, including the Netherlands, Australia and Japan. Some estimates put the proportion of consumption due to standby power as high as 13%.

From the US department of Energy:

"Many appliances continue to draw a small amount of power when they are switched off. These "phantom" loads occur in most appliances that use electricity, such as VCRs, televisions, stereos, computers, and kitchen appliances. In the average home, 75% of the electricity used to power home electronics is consumed while the products are turned off. This can be avoided by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance."

A careful analysis of the energy cost would also account for the effects of standby power on heating and cooling. During warm periods, more energy will be consumed for cooling. During cool periods, the heat generated by devices on standby may slightly reduce the need to heat a building by other methods. But electric heat is generally less energy efficient than other forms of heating. The net effect on energy efficiency however depends on the climate and heating and cooling methods used.

Fire risks

The subject of fire risk due to leaving a device in standby mode is a popular debate. There are reported cases where televisions have caught on fire in stand-by mode. The contributing factors for such fires include:

• Humid environments
• Lightning storms
• Age of the appliance

Modern televisions use only a small fraction of the power in standby mode (typically less than 10W). A modern HD LCD television may use only 1W or less when in standby mode (compared to 80-125W during standard operation).

Policy

Further information: One Watt Initiative

In July 2001, U.S. President George W. Bush signed an Executive Order directing federal agencies to "purchase products that use no more than one watt in their standby power consuming mode".

In July 2006, the British Government announced it would outlaw televisions and video players that exceed the maximum standby-mode power consumption standard (1 watt).

In July 2007, California's 2005 appliance standards came into effect, limiting external power supply standby power to 0.5 Watts.

In July 2008, the European Union regulatory committee accepted a proposal to reduce standby power consumption to either 1 or 2 Watts by 2010. It also warrants a further reduction to 0.5 or 1 Watt by 2012.

Estimating total

An estimate of how much standby power is used can be made using tables of standby power used by typical devices. Measurement of the overall standby power can be made by observing how fast electricity is used when all devices are turned off, or when standard loads are in use.

Identifying devices

A power meter can be used to find out how much energy is used by standby power. Power meters can often be borrowed from the local power authorities or a local public library.

Devices and functions that can consume standby power

• Power supplies, transformers and inefficient electronic devices.
• VCRs, DVD players and some audio systems.
• Set-top boxes
• Microwave ovens
• Computers, digital monitors and printers
• TVs, if not switched off from the power switch (if they have one).
• Air conditioning systems with remote control.
• Devices with "Instant on" functions, with remote control receivers, or waiting for the user to interact.
• Devices with a stand-by light or clock.
• Small transformers (such as wall warts) that convert AC electricity into DC electricity, whether or not they are powering any device.
• Devices that get warm or that have warm transformers when they are off.
• Some home video game consoles (e.g. Nintendo Wii & Sony PlayStation 3)

• 
  Standby Indicator
• 
  Power supply
• 
  Temperature display

Reducing consumption

There are a few simple methods to reduce standby power. The easiest way to do that is to simply unplug the unused devices. To switch off several devices that are often used together such as a PC, a monitor and a printer it is advisable to use a switchable power bar or surge protector with multiple sockets. Another alternative is to consider buying energy saving devices or devices that offer a real off switch. Replacing battery powered devices, such as cordless phones or rechargeable razors with corded alternatives not only cuts down on the standby power required to charge the battery, but also reduces energy lost in battery charging and discharging inefficiencies.

Switching devices on or off can be automated. Timers can be used to turn off standby power to devices that are unused on a regular schedule. Switches can turn the power off when the connected device goes into standby (e.g. Standby Plug), or that turn on/off other outlets when a device is turned on or off are also available (e.g. USB Eco Powerstrip, Mini Power Minder, SmartStrip, IntelliPanel). Switches can turn on/off based on activity sensors (e.g., Wattstopper). Home automation sensors, switches and controllers can be used to handle more complex sensing and switching. However, many of these devices in their turn require standby power (for instance, the SmartStrip uses 0.28 watts in standby.), as well as requiring energy and resources to make and recycle the device, so care should be taken to assure reduction in power use.

• 
  switchable multiple socket
• a socket which automatically switches off when it detects a device has gone into standby
  a socket which automatically switches off when it detects a device has gone into standby
• 

Some devices that use standby power may not turn on when power is removed and then reapplied by means of an external switch. A capacitor connected in parallel with the power switch can act as a momentary contact switch to turn on such devices when power is applied.

Some computers allow reducing of standby power by turning off components that use power when in standby mode. For instance, disabling Wake on LAN, wake on modem, wake on keyboard or USB may reduce power when in standby. It may be possible to disable such features that you do not use in the computer's BIOS setup.

Terms and Usage History

Phantom Load

The earliest known use of the term Phantom load was in "It's Gotta Be Spring" by Brian Green (N6HWY) on page 25 of Home Power magazine #11, the June/July 1989 issue.

See also

• Green computing
• Low-power electronics
• Miscellaneous electric load
• Wall wart

External links

• Standby Power Home Page, Lawrence Berkeley National Laboratory
• Official Energy Star Website, Energy Star
• International Conference on Standby Power, New Delhi INDIA
• Pulling the plug on standby power, Mar 9th 2006, The Economist
• “Phantom Loads”
• “Is a Phantom Stealing Your Electricity?”
• EU States Endorse Steps to Cut Standby Power Use