Whenever I go into a study lounge or library I always choose a seat as close to an outlet as possible. Never mind the window seat, I want a spot where I can plug my computer in and charge my phone. However, this tendency of mine is extremely ironic considering I am studying environmental policy. Prompted by my own usage patterns, I decided to find out how much energy is used by the increasingly popular smartphones at Boston University.
At a time when many people consider iPhones, Droids and BlackBerrys to be a necessity, more people are choosing the outlet seat over the window seat. After conducting a quick survey, I found that 77 percent of the students I sampled owned a smartphone. Seventy-seven percent of these owners said they charged their phones at least five times a week, probably because 80 percent said they never turn their phones off. But how much energy does this actually amount to? Using a Kill-A-Watt Meter, I found that an iPhone uses approximately 6.4 watt-hours of energy every hour when charging. Therefore, if 77 percent of undergraduates at BU (14,271 students) all charged their martphones for one hour, this would use 91,334 watt-hours, or 91.334kWh, of energy. This amount of energy is equal to over 1500 60-watt bulbs turned on for an hour. And just imagine, most people said they charge their phones at least five times a week.
So what are we to do? I am not about to give up my cell phone and I certainly am not about to ask you to do the same. One easy option is to turn down the brightness of your smartphone screen. Using a Kill-A-Watt Meter I was able to measure that a charging iPhone uses six watts when the screen is set to the dimmest setting but 6.4 watts when the screen is on the brightest setting. If every student at BU were able to dim their smartphone that would save up to 5700 watts, which is equal to 95 light bulbs. Another option is to switch off the 3G capability on your smartphone as, similar to an iPhone, the battery will last up to four hours longer. Another thing you could do would be to simply turn off your phone. The fact that less than two percent of surveyed students said they turn off their phones at night suggests that people like to stay connected. However, if everyone at BU turned off their phone while they slept, there could be up to a 33 percent reduction in the amount of energy used to charge smartphones across campus. I hope my investigation will get you curious about how much energy you’re using and how you can use your gadgets in a more sustainable manner.
- Megan Ware, CAS ‘13
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