Survey of Residential Plug LoadsIn 2006, Ecova (Formerly Ecos) — in cooperation with RLW Analytics and Lawrence Berkley National Laboratory and with funding from the California Energy Commission’s Public Interest Energy Research (PIER) program — undertook one of the first comprehensive studies of electric plug load devices in the United States. A plug load is any electrical device that ultimately receives power from an ac wall outlet, ranging from cell phones to small appliances [1]. The research sought to better understand how and when consumers use a subset of plug load products in their homes — particular electronics and appliances with rechargeable batteries — and where significant energy savings opportunities might exist. The team conducted phone surveys of 300 California homes and then metered the plug loads in 50 of these homes using highly accurate plug load power meters. The researchers obtained weeklong power and usage pattern measurements for nearly 700 plug load products in the selected homes. For more information about this research, please contact Laura Moorefield, Research & Policy Manager, Ecova (lmoorefield@ecova.com).

The results provide an updated synopsis of the energy used by plug loads and miscellaneous devices in total, but the study also provides detail on the largest energy users and corresponding energy savings opportunities:

• Electronic products use anywhere from 1,069 and 1,207 kWh in a typical home, costing each homeowner approximately $150 per year to operate.
• Plug load energy consumption is at least 9% of electricity use in a typical U.S. household and more than 15% for a typical California home.
• On the national scale, these products consume 114 to 146 billion kWh per year or between 3% and 4% of all electricity used in the country. This is enough energy to fully power all of the homes in California and Washington State combined for one year.
• Entertainment products (TVs and their associated peripherals such as DVD players, cable/satellite boxes, etc.) and information technology (computers and their associated peripherals such as printers, scanners, modems, etc.) account for over 90% of the electricity used by plug load devices in a typical home. These two categories of products also represent the largest opportunities for energy savings through the use of more efficient products.

Some of the most effective ways for policymakers and electric utilities to tap into energy savings opportunities in these products are:

• Further tightening standby mode requirements
• Calling for higher efficiency when the product is in operation or “active mode”
• Creating whole-product efficiency specifications that address energy savings opportunities that are unique to individual end uses of electricity like computers or televisions
• Adopting common denominator strategies for small products (where product level specific specifications are less feasible) to improve the efficiency of hundreds of low power products that use external power supplies or battery charger systems

Survey of Office Plug Loads
In 2007 and 2008, Ecova (Formerly Ecos) and RLW Analytics conducted a plug load field monitoring study in commercial offices in California. Researchers visited 47 offices and compiled an inventory of all plug load devices found at each of the sites. The research team then installed plug load meters on a subset of devices in 25 of these offices. This is the first study to actually measure how products are used in the office environment.  In total, the team inventoried nearly 7,000 plug load devices and collected meter data from 470 plug load devices. While the scale of this study was not large enough to be statistically valid for all of California, the findings provide detailed insights into how many and what types of plug loads are found in California’s offices, how these devices operate in their everyday office settings, and how much energy they consume.  For more information about this research, please contact Laura Moorefield, Research & Policy Manager, Ecova (lmoorefield@ecova.com).

Breakdown of Commercial Plug Load Energy Use

Key Findings

• Plug loads consumed up to 20% of total office electricity in the sites that participated in the study
• In some spaces, plug load energy use can outpace hard-wired lighting energy use.
• Computers were the single largest office plug load end use. Their energy consumption alone accounted for 48% of total office plug load energy use in the study. 
• Monitors were the second largest plug load accounting for 18% of total office plug load in this study.
• The average desktop computer consumes 266 kWh per year compared with 58 kWh per year for the average notebook computer.
• The average CRT monitor consumes approximately 128 kWh per year, and the average LCD monitor consumes 80 kWh per year.
• The average laser printer in the study consumed 170 kWh per year.  Laser multifunction devices followed suit, consuming 171 kWh per year on average.
• Much of the energy use of computers and their peripherals could be eliminated by enabling power management settings and use of other control devices such as smart plug strips.

Some of the most effective ways for policymakers and electric utilities to tap into plug load energy savings opportunities are:

• Promoting and/or requiring office electronics with automatic controls enabled to power the device down to a low power mode when not in use
• Widespread implementation of power supply efficiency programs such as ENERGY STAR, 80 PLUS, and Climate Savers.
• Promoting smart plug strips adoption for computer work station peripherals
• Automatic controls, already effectively used with hard-wired lighting, could be required by building codes to operate wall outlets
• Building codes could consider a requirement for switched outlets.

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1.  White goods such as refrigerators were not considered in the scope of this research because their energy use has been well-researched.