A new ‘clean energy’ mode on iPhone popped up on the as part of iOS 16.1 and is designed to make the iPhone select clean energy when available based on data from the electricity grid.

However Apple fanboys have noticed that with the mode switched on their iPhones were not charging as quickly. This made them read Apple's marketing bumph where they were reassured:

"When Clean Energy Charging is enabled and you connect your iPhone to a charger, your iPhone gets a forecast of the carbon emissions in your local energy grid and uses it to charge your iPhone during times of cleaner energy production."

Apple insists that the "feature" only engages in ‘known’ locations such as your home or work locations – and engages when phones are on charge for longer periods.

Clean Energy Charging works together with Optimised Battery Charging to learn your charging habits. Clean Energy Charging engages only where you spend the most time and regularly charge your iPhone for long periods of time, such as your home and place of work.

Fortunately the Clean Energy Charging feature works only in the US so European users are not seeing their phone charging slow down. Apple tends to roll out "advanced features" in the US before bringing them to other regions. Quite why Apple thinks it is a good idea to mess around with the battery all the time is anyone's guess. While it is getting a reputation for this sort of thing, trying to pin it on saving the planet is a little cynical, even for Apple. 

The feature can easily be switched off: to do so go to Settings > Battery > Battery Health & Charging and turn off Clean Energy Charging.

"When Clean Energy Charging suspends charging, a notification on the Lock Screen says when your iPhone will be fully charged. If you need to have your iPhone fully charged sooner, touch and hold the notification and then tap Charge Now," adds Apple.