ipad Electricity Consumption in Relation to Other Energy Consuming Devices - Executive Summary

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Edgar Benson
8 years ago
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1 ipad Electricity Consumption in Relation to Other Energy Consuming Devices - Executive Summary Overview In growing numbers, consumers are buying mobile electronic devices that reflect rapidly changing features and battery technology. The energy each device consumes is relatively small, but as new technologies are adopted by millions of consumers it is important to understand the aggregate and cumulative effects of their use on electricity consumption. One example is Apple Inc. s ipad tablet. Tens of millions of these devices have been sold, and researchers at the Electric Power Research Institute (EPRI) were inspired to investigate the aggregated and cumulative impact of these devices on electricity load. Energy Consumption for Various Devices The U.S. Department of Energy s Annual Energy Outlook (AEO) for 2011 projects that electricity consumption for various household devices will increase as new products enter the marketplace. The AEO estimates that electricity use grows at 0.7 percent per year, increasing from 42 percent of total residential delivered energy consumption in 2009 to 47 percent in 2035 (figure below). (Note that federal lighting standards will lead to a decline in energy use for lighting, as low-efficacy incandescent lamps are replaced by compact fluorescent (CFL), LED, and other high-efficiency lamps.) (Source: Annual Energy Outlook 2011) For the other category, which includes tablets and other devices, electricity consumption will continue to grow and will consume more electricity collectively than some major appliances such as clothes washers or refrigerators. Projections account for devices now in the marketplace and future products that consumers will buy.

The energy each device consumes is relatively small, but as new technologies are adopted by millions of consumers it is important to understand the aggregate and cumulative effects of their use on

2 One such device that illustrates rapid adoption and market penetration is the ipad from Apple Inc., a portable tablet device that fell outside both the PC and Laptop categories when launched in TAEO has categorized it as other while it has rapidly gained popularity among consumers, with sales exceeding 7 million units in Apple released its second generation ipad in the first quarter of 2011 and a newer version of the tablet in the first quarter of According to the company, total sales for the device have climbed to 67 million units and that sales trend is expected to continue. (see figure below). 18,000,000 Apple ipad Sales 16,000,000 15,434,000 14,000,000 12,000,000 11,123,000 11,798,000 10,000,000 9,246,000 8,000,000 7,331,000 6,000,000 4,000,000 3,270,000 4,188,000 4,694,000 2,000, Q Q Q Q Q Q Q Q Q (Source: Apple s Quarterly Reports) EPRI tested three generations of ipads, along with other portable electronic devices. Results are summarized below. It is noted that Apple increased ipad battery capacity from 25 watt-hours to 42.5 Watt-hours in the latest generation ipad, to help power its dual core A5X chip with quad-core graphics and new display technology. The charging test results show that the new ipad takes 11.9 kwh per year compared to older versions of ipad, which consume 7.2kWh per year (assuming on average that the ipad is charged every other day). In March 2012, just three days after the new ipad was introduced to the market, sales exceeded three million units in the United States, according to Apple. The annual energy consumption of these three ipad models would be comparable to the energy used in 3,000 U.S. homes. At the time of this report, 67 million ipads of all three generations have been sold worldwide, according to Apple. EPRI calculates the average energy used by all ipad s is approximately 590 gigawatt hours (GWh). In a scenario in which the number of ipads in use tripled over the next two years, the energy required would be nearly equivalent to two 250-megawatt (MW) power plants operating at a 50 percent 2

Apple released its second generation ipad in the first quarter of 2011 and a newer version of the tablet in the first quarter of 2012.

3 utilization rate. A quadrupling of sales in two years would require energy generated by three 250-MW power plants. A 250-MW plant at a 50 percent utilization rate produces 1095 GWh of electricity per year. Assumptions /Testing Methodology EPRI used a "Watts up / PRO ES" meter, a plug-in device capable of recording power (Watts) and energy (Watt-hour) usage of 120V devices. Batteries were brought to zero percent charge and then plugged into the Watts up / PRO ES meter. The devices were then fully charged. The meter calculates the device s energy use by integrating power drawn by the device over time, measuring the energy use per charge cycle. The tests assumed an average user charges phones, ipods and other smaller devices daily. For the ipad, calculations assumed every-other-day charging. For appliances that do not operate on batteries, such as digital photo frames, televisions, set-top boxes etc., average power consumption is calculated using the average annual operating hours multiplied by the average power consumption. The average operating hours for various devices are available from sources such as ENERGY STAR, Bureau of Labor Statistics, California Energy Commission and U.S. Department of Energy. U.S. Energy Information Administration (EIA) releases the national average electricity cost per year which can be viewed at This 3

Assumptions /Testing Methodology EPRI used a "Watts up / PRO ES" meter, a plug-in device capable of recording power (Watts) and energy (Watt-hour) usage of 120V devices.

4 average electricity cost multiplied by the annual energy use gives the total annual electricity usage cost for the devices. About EPRI The Electric Power Research Institute, Inc. (EPRI, conducts research and development relating to the generation, delivery and use of electricity for the benefit of the public. An independent, nonprofit organization, EPRI brings together experts from academia and industry as well as its own scientists and engineers to help address challenges in electricity generation, delivery and use, including health, safety and the environment. EPRI's members represent more than 90 percent of the electricity generated and delivered in the United States, and international participation extends to 40 countries. EPRI's principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.; and Lenox, Mass. # # # Contact: Don Kintner EPRI Manager, Communications 4

An independent, nonprofit organization, EPRI brings together experts from academia and industry as well as its own scientists and engineers to help address challenges in electricity generation,

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