Apple’s Clean Energy Charging works by accessing a forecast of the carbon emissions on your local energy grid and then only charging when those emissions are lower. This may sound like an esoteric change, save for two factors: it’s enabled by default on all iPhones running iOS 16.1, and hundreds of millions of iPhones are in use worldwide, all of which require charging. “There are 16 billion mobile devices worldwide that need to be charged on a daily basis. The average consumption of these devices can be more than the average consumption of a country like Denmark,” Aimee Howard, a specialist in power electronics for renewable energy with 28 years in the aviation industry developing power electronics for sustainable manufacturing, told Lifewire via email.

Greener Grid

The first thought that came to mind when I saw this feature was, “Why doesn’t the grid store its own lower-carbon power and use it instead of producing more polluting energy?” But, of course, the answer is more complicated.  The grid can store electricity, and the ways it manages to do this are odd enough that it’s worth a look here. This is especially relevant when using renewable energy sources like solar, wind, or wave power, as these produce electricity on their own schedule, not necessarily when demand is at its peak.  Batteries might be the first option you think of, but they have the same disadvantages as the batteries in our gadgets. They often use expensive lithium-ion, for example, and can be hazardous to the environment if not disposed of correctly. And electricity doesn’t have to be stored as electricity. It can be converted to other forms of energy.  For example, using excess power to pump water back up to a reservoir stores the power as potential energy, which can be released by letting the water flow back down and using it to generate electricity. It can also be stored in a flywheel as kinetic energy. According to the EPA, these flywheels can rotate up to 60,000 RPM and spin on magnetic bearings in a vacuum to reduce drag and energy loss.  Electricity can also be stored in compressed air and ice.  The trouble with all of these is they’re inefficient. Energy is used in the conversion and wasted as heat. That’s where Clean Energy Charging comes in. 

Clean Energy Charging

By waiting for times of lower carbon emissions, you use excess energy directly instead of storing it. This is great for devices you charge because they store the energy until it’s needed. It can also work in some household situations; some countries offer cheaper electricity at off-peak times, so you can choose to run the dishwasher overnight, for example. Other tasks are more time critical. You have to cook your dinner at dinnertime, for example, unless you’re really, really into cold cuts and leftovers.  Apple’s switch to Clean Energy Charging might not make much of a difference to you as an individual, but because the installed base of iPhones is so huge, the impact can be equally massive.  “[S]mall adjustments add up over time. What Apple is doing is making it easier for iPhone users to become more aware of their role in reducing carbon emissions,” Sarah Jameson of Green Building Elements told Lifewire via email. “It serves as a reminder of the importance of reducing carbon emissions and that even the most mundane activities, such as charging your phone when power grids are less constrained and more clean energy capacity is available, are significant in the grand scheme of things.” And this feature may raise awareness about how the energy grid works and how we can save resources and money in other areas, not just when charging our phones.  Right now, this is iPhone- and US-only, but if it works out and the energy forecast data is available, then there’s no reason not to expect this to roll out to Macs, iPads, and Apple Watches. In this case, the impact could be huge.