What Energy Do Cell Phones Use?


People who are concerned about energy use and greenhouse gas emissions may want to know how much energy their cell phones use and whether there are any alternatives.


  • Cell phone chargers use energy when they charge the phone battery and also when they are not charging the phone but are left plugged in. According to a study by the Lawrence Berkeley National Laboratories, the average cell phone charger uses 3.68 watts of power while it is charging, 2.24 watts of power when it is on but the cell phone is no longer charging and an average of 0.26 watts when it is plugged in but not on.

Annual Energy Use

  • Assuming that an average cell phone is charged for three hours every night and the charger is left on for the remaining five hours each night, the annual energy use would be about 8.1 kilowatt-hours (kWh). If the charger is left plugged in all the time when it is not in use, that would add about 1.5 kWh per year. For comparison, switching a standard incandescent light bulb to a compact fluorescent bulb saves on average 125 kWh per year.

Energy-Efficient Chargers

  • The U.S. Department of Energy and Environmental Protection Agency Energy Star Program lists chargers that meet their efficiency standards. Chargers that qualify for the Energy Star on average use 30 percent less energy than standard chargers.

Solar Batteries and Chargers

  • Some manufacturers have produced cell phones that run on solar batteries, which may be recharged in the sun or even in artificial light. There are also solar chargers, which can use either solar power or electric power to recharge the phone.

Other Considerations

  • The average ownership of a cell phone is a year and a half. Although it does not take a lot of energy to produce one phone, the energy needed to produce millions of new phones adds up. A new charger is often needed with a new phone, but the International Telephone Union is working on making chargers universal so less energy will be needed to produce new ones.

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