Is your iPhone using more energy annually than your fridge?
That's the surprising -- and increasingly controversial -- claim laid out by Digital Power CEO Mark P. Mills in his new paper, "The Cloud Begins With Coal: Big Data, Big Networks, Big Infrastructure, and Big Power."
From the paper:
Reduced to personal terms, although charging up a single tablet or smart phone requires a negligible amount of electricity, using either to watch an hour of video weekly consumes annually more electricity in the remote networks than two new refrigerators use in a year. And as the world continues to electrify, migrating towards one refrigerator per household, it also evolves towards several smartphones and equivalent per person.
The claim is based on a smartphone's total energy usage per year, meaning Mills' conclusion takes into account the sum of energy used for wireless connections, data usage and battery charging.
TIME reached out to Max Luke, a policy associate at the Breakthrough Institute, to help clarify the calculations used by Mills. In an email to TIME, Luke wrote:
Last year the average iPhone customer used 1.58 GB of data a month, which times 12 is 19 GB per year. The most recent data put out by a ATKearney for mobile industry association GSMA (p. 69) says that each GB requires 19 kW. That means the average iPhone uses (19kw X 19 GB) 361 kwh of electricity per year. In addition, ATKearney calculates each connection at 23.4 kWh. That brings the total to 384.4 kWh. The electricity used annually to charge the iPhone is 3.5 kWh, raising the total to 388 kWh per year. EPA’s Energy Star shows refrigerators with efficiency as low as 322 kWh annually.
However, not everyone is as convinced by Mills' report, which was sponsored by the National Mining Association and the American Coalition for Clean Coal Energy. MSN News evaluated the study and found Mills' claim about iPhone energy "false."
The MSN article claims that Mills is actually recycling similar research he published in 2000 about the amount of energy needed to power a Palm Pilot vs. a refrigerator. Jonathan Koomey, a research fellow at the Steyer-Taylor Center for Energy Policy and Finance at Stanford University, even said he had debunked Mills' previous claims and called his latest paper "outrageous."
"What we found in 2000 is that a refrigerator used 2,000 times more electricity than the networking electricity of a wireless Palm Pilot," Koomey told MSN. "He is not a credible source of information."
The TIME piece notes that smartphone energy usage varies widely depending on wireless connections and data, concluding that Mills' numbers imply very heavy usage, or a "worst-case model" of energy usage.
While Mills did not immediately respond to a request for comment, he told MSN in an email that his facts and figures were accurate and not meant to promote the coal industry, which sponsored the paper.
Mills also defended his research on social media: