Wireless Charging Is a Disaster Waiting to Happen

We crunched the numbers on just how inefficient wireless charging is — and the results are pretty shocking

Wireless charging is increasingly common in modern smartphones, and there’s even speculation that Apple might ditch charging via a cable entirely in the near future. But the slight convenience of juicing up your phone by plopping it onto a pad rather than plugging it in comes with a surprisingly robust environmental cost. According to new calculations from OneZero and iFixit, wireless charging is drastically less efficient than charging with a cord, so much so that the widespread adoption of this technology could necessitate the construction of dozens of new power plants around the world. (Unless manufacturers find other ways to make up for the energy drain, of course.)

On paper, wireless charging sounds appealing. Just drop a phone down on a charger and it will start charging. There’s no wear and tear on charging ports, and chargers can even be built into furniture. Not all of the energy that comes out of a wall outlet, however, ends up in a phone’s battery. Some of it gets lost in the process as heat.

While this is true of all forms of charging to a certain extent, wireless chargers lose a lot of energy compared to cables. They get even less efficient when the coils in the phone aren’t aligned properly with the coils in the charging pad, a surprisingly common problem.

To get a sense of how much extra power is lost when using wireless charging versus wired charging in the real world, I tested a Pixel 4 using multiple wireless chargers, as well as the standard charging cable that comes with the phone. I used a high-precision power meter that sits between the charging block and the power outlet to measure power consumption.

In my tests, I found that wireless charging used, on average, around 47% more power than a cable.

Charging the phone from completely dead to 100% using a cable took an average of 14.26 watt-hours (Wh). Using a wireless charger took, on average, 21.01 Wh. That comes out to slightly more than 47% more energy for the convenience of not plugging in a cable. In other words, the phone had to work harder, generate more heat…