How much energy does it take to power your smartphone addiction?

The average iPhone uses more energy than a midsize refrigerator, says a new paper by Mark Mills, CEO of Digital Power Group, a tech investment advisory. A midsize refrigerator that qualifies for the Environmental Protection Agency's Energy Star rating uses about 322 kW-h a year, while your iPhone uses about 361 kW-h if you stack up wireless connections, data usage, and battery charging.

The paper, rather ominously titled "The Cloud Begins With Coal: Big Data, Big Networks, Big Infrastructure, and Big Power," details how the world's Information Communication Technology (ITC) ecosystem — which includes smartphones, those high-powered Bloomberg terminals on trading floors, and server farms that span the size of seven football fields — are taking up a larger and larger slice of the world's energy pie.

The slice right now, according to Mills, is about 10 percent, or 1,500 terawatt hours of energy per year. (For context, one terawatt hour is one trillion watt hours, and one watt terawatt hour can power about 90,000 homes per year) Much of that energy is going to server farms, those giant clusters of computer servers that power "the cloud," as well as wireless networks.



And the ITC ecosystem is expected to require more energy as time goes on. Part of the reason is that unlike a flashlight or an air conditioner, much of the technology we're wired to never goes to sleep. Think about it: Who actually turns off their cell phones at night?

On top of that, our devices are requiring more and more power. "As anyone who has ever tried to husband the battery of a dying smartphone knows, transmitting wireless data — whether via 3G or wi-fi — adds significantly to power use. As the cloud grows bigger and bigger, and we put more and more of our devices on wireless networks, we’ll need more and more electricity," says Bryan Walsh at TIME.

All added up, Mills calculates that it now takes more energy to stream a high-def movie than to manufacture and ship a DVD of the same film.

So where does coal come into the equation? To start with, the National Mining Association and the American Coalition for Clean Coal Electricity sponsored Mills' study. Coal is still the largest source of electricity in the world, so it's safe to say it's playing a huge role in keeping us connected.

Says Mills: “Coal’s dominance arises from the importance of keeping costs down while providing ever-greater quantities of energy to the growing economies, and as the IEA recently noted, the absence of cost-effective alternatives at the scales the world needs.”

The only fix, however, is to keep developing alternatives, says Breakthrough:

If Mills is right that ICT will fundamentally change the way we use electricity — by putting a premium on reliable, round-the-clock power generation — we need to be thinking seriously about how we can power the information sector with cheaper, cleaner alternatives to coal. This will require making technologies that can provide reliable, baseload power cheaper and more readily available. [Breakthrough]