Vampire Power

Also called Standby power, refers to the electric power consumed by electronic appliances while in a standby mode. A very common "electricity vampire" is a power adaptor which has no power-off switch. While this consumption of power may be used to provide useful functions for appliances such as remote controls and digital clocks to the user, most power consumed by non-operational devices is considered wasted as in the idle satellite TV receiver in the picture to the right. Advocates of energy conservation sometimes use the term "wall warts" to describe devices that stay plugged in and using power without performing a useful purpose.

Where you will find Vampire Power:

• Power supplies, transformers and ineffective electronic devices and battery chargers. Those constantly generate heat that can't be further used.
• "Instant on" functions, like remote control receivers, waiting for the user to interact.
• Displays and condition indicators, such as clocks, temperature gages and status indicators, for instance the standby LEDs on electronic devices, although the power used by such indicators is very small (milliwatt range).
• Power bricks for computers, printers and rechargeable batteries.

Although the power needed for functions like displays, indicators, and remote control receivers is only in the milliwatt range, power supplies that are used to convert the AC line voltage to the low voltage needed to perform the functions typically operate at very low efficiency when they are operating at low power. As a result, the power consumed from the mains is often in the range of 1 W to 10 W even when only a few tens of mW or less are needed.

The ever increasing awareness of global warming has thrust energy efficiency to the forefront of public opinion. The wasted standby power of household electronic devices is typically very small, but the sum of all such devices within the household becomes significant.

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 as in the idle mobile phone chargers thermal image to the right. 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 ener

gy, 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. That same year, a similar study in France 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%.

These numbers only indicate the power consumption of the devices on standby, however, and not the effect on total power consumption. As the electricity is transformed into heat energy, this effect can be far off, given the right conditions. A household or building that uses air conditioning to regulate down the temperature inside the building will in fact use more power to counter the effect of the standby power. Conversely in colder climates, the heat generated by devices on standby may slightly reduce the need to heat a building by other methods. The net effect on energy efficiency however depends on the normal heating method used.

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".

Simple Solutions

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 consisting of multiple sockets. Another alternative is to consider buying energy saving devices or devices that offer a real off switch. To realize how much energy is used by standby power, a power meter can often be lent by the local power authorities or a local public library.

Content source: Wikipedia.org