Leaking Electricity: Standby and Off-Mode Power Consumption in Consumer Electronics and Household Appliances

Jennifer Thorne and Margaret Suozzo

February, 1998

Home electronics and small household appliances (such as televisions (TVs), video cassette recorders (VCRs), telephone answering machines, cordless phones, portable power tools, office equipment, etc.) draw energy not only when they are in use, but also when the power is ostensibly off. This phenomenon is known as "leaking electricity." Leaking electricity is responsible for an estimated 45 billion kilowatt-hours (kWh) of electricity consumed by U.S. households each year—nearly 5 percent of total residential electricity use—and costs U.S. consumers more than $3.5 billion annually. In the past few years, researchers in the United States, Europe, Japan, and elsewhere have made considerable progress in understanding the energy losses, potential savings, and markets for products that leak electricity. This information is enabling policymakers to make better decisions about effective approaches that they can take to address leaking electricity. At this point, at least one significant joint government-industry initiative has begun in the United States and others are being discussed. Not surprisingly, these initiatives focus on those markets where the greatest potential energy savings lie. Additional opportunities exist to save a large fraction of the remaining standby and off-mode power waste. Preliminary estimates show that leaking electricity could be reduced by almost 75 percent through the use of improved components and product designs.

Introduction

Many consumer electronics products and small appliances found in homes (and businesses) actually consume electricity when they are thought to be "off." You can verify this by touching the wall transformer for your cordless phone, hand-held vacuum, or portable drill—it's warm. Or by observing the light-emitting diode (LED) clock display on your microwave, VCR, or audio system. The electricity consumed by a device when it is switched off and not performing its primary function is known as "leaking electricity."

Over the past few years, researchers in the United States, Europe, Japan and elsewhere have made considerable progress in understanding the energy losses, potential savings, and markets for products that leak electricity. Current projections indicate that miscellaneous electricity, the category in which leaking electricity falls, will account for more than 90 percent of the growth in carbon emissions from the buildings sector between 1990 and 2010 (Koomey et al. 1997). Leaking electricity arises from several sources, including: (1) components that provide a small service that is auxiliary to the product's primary function, such as powering a small display for a clock or charging a battery; (2) components for products that are always ready to be activated, such as remote control or other sensors (e.g., for telephone signal detection); and (3) components that simply waste energy, where power may be supplied to a transformer or integrated circuit that provides no useful function when the device is turned "off" (Rainer, Greenberg, and Meier 1996). Table 1 lists product categories and provides examples of the devices contributing to leaking electricity.

Table 1: Leaking Electricity Product Categories

Metering demonstrates that the power draw in standby and off-mode varies widely among different models, regardless of features or functions. Whereas some products exhibit losses greater than 20 watts, low-loss products in the same categories with similar performance and features can draw less than 1 watt. Clearly, significant standby and off-mode power reductions are achievable through the application of more efficient power supplies, smarter batteries, and improved integrated circuitry. Through intelligent public policies and greater consumer awareness, we can begin to address the financial and environmental costs of standby and off-mode power losses.

The remainder of this report presents current estimates of leaking electricity and the basis of these estimates, alternative design options that can be and have been applied to reduce standby and off-mode losses, policy options for reducing leaking electricity (including domestic and international activities), and actions that consumers can take to minimize standby and off-mode power waste in their homes.

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