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.
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 2010. TAEO
has categorized it as “other” while it has rapidly gained popularity among consumers, with sales
exceeding 7 million units in 2010. 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and a newer version of the tablet in the first quarter of 2012. 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).
Apple iPad Sales
18,000,000
16,000,000
15,434,000
14,000,000
11,798,000
12,000,000
11,123,000
10,000,000
9,246,000
8,000,000
7,331,000
6,000,000
4,694,000
4,188,000
4,000,000
3,270,000
2,000,000
-
Q2 2010
Q3 2010
Q4 2010
Q1 2011
Q2 2011
Q3 2011
Q4 2011
Q1 2012
Q2 2012
(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
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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 http://www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_3 . This
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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, www.epri.com) 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.
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Contact:
Don Kintner
EPRI
Manager, Communications
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[email protected]
704-595-2506
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