Clean Energy Charging on iPhone: What It Means and Should You Turn It Off?

If your iPhone’s Lock Screen says Clean Energy Charging and the battery is stuck at 80% overnight, nothing is wrong. Your phone is deliberately waiting for cleaner electricity. This guide explains what clean energy charging is, how the iPhone decides when the grid is “clean”, whether it affects battery health or charging speed, how to turn it off, and — with the arithmetic shown — how much carbon and money it actually saves. For background on what makes electricity clean in the first place, see our clean energy guide.

What is Clean Energy Charging on iPhone?

Clean Energy Charging is an iOS feature that times the end of a long charging session for hours when your local electricity grid is forecast to emit less carbon. Apple introduced it in iOS 16.1 in October 2022. It is available in the United States and turned on by default (Apple).

In plain terms: when you plug in at bedtime, your iPhone charges to around 80% normally, then looks at a forecast of carbon emissions for your area and schedules the rest of the charge for the cleanest window before you usually unplug. You still wake up to a full phone.

What does it mean when my iPhone says “Clean Energy Charging”?

It means charging is paused on purpose and the phone has scheduled the rest of the charge for a lower-carbon time. The Lock Screen notification shows when it expects to be fully charged, for example “Charging scheduled to finish by 10:30 AM” (Apple).

You can override it at any time: touch and hold the notification and tap Charge Now. The phone then charges straight to its limit.

How does Clean Energy Charging work?

The iPhone combines your learned charging routine with a forecast of grid carbon intensity for your location, then shifts the final part of the charge to the cleanest forecast hours. The pieces:

1. Your routine. On-device machine learning (the same system behind Optimized Battery Charging) learns where and when you charge for long periods, such as overnight at home or all day at a desk (Apple).
2. Your location. To get a forecast for your local grid, the feature needs Location Services with System Customization and Significant Locations & Routes switched on. Apple says the location information used for this feature is not sent to Apple.
3. A carbon forecast. The phone obtains a forecast of carbon emissions on your local grid. Apple has not published which data provider it uses.
4. The schedule. It charges to about 80%, pauses, and resumes in the forecast lower-carbon window, finishing before your predicted unplug time.

It does not engage if your charging habits vary or you are in a new location (Apple). That is why it rarely appears at a friend’s house or on a road trip.

Why is grid electricity “cleaner” at some hours?

Every grid runs a changing mix of power plants. When the wind is strong overnight or the sun is high at midday, wind and solar supply more of the mix and fossil plants throttle back, so each kWh carries less CO2. In the evening peak, gas “peaker” plants often fill the gap. The EIA’s Hourly Electric Grid Monitor shows this hour-by-hour shift in generation by fuel and CO2 emissions for each US balancing authority.

Typical situation	Grid mix	Carbon per kWh
Sunny midday, solar-heavy grids (California, Texas)	High solar share	Lower
Windy night, wind-heavy grids (Texas, Great Plains, Midwest)	High wind share	Lower
Early evening peak, demand high and solar fading	More gas peaker plants	Higher
Calm, dark night on a coal-heavy grid	More coal and gas baseload	Higher

How much the iPhone can gain depends on how much your local grid swings during the hours you are plugged in. A grid with lots of wind that blows at night gives the feature more to work with than a grid whose mix is flat overnight. Learn more about the sources behind those swings in our renewable energy sources guide.

Clean Energy Charging vs Optimized Battery Charging vs Charge Limit

Optimized Battery Charging protects the battery; Clean Energy Charging picks the cleanest hours; Charge Limit caps the maximum. They overlap, which is why people mix them up.

Feature	Goal	Introduced	Where to find it
Optimized Battery Charging	Reduce battery wear by limiting time spent at 100%	iOS 13 (2019)	Settings › Battery › Charging (iPhone 15+) / Battery Health & Charging (iPhone 14 and earlier)
Clean Energy Charging	Shift the end of the charge to lower-carbon grid hours	iOS 16.1 (2022), US only	Same menu
Charge Limit	Stop charging at a set level	iPhone 15 and later	Settings › Battery › Charging; choose 80–100% in 5% steps

On iPhone 15 and later, Optimized Battery Charging is available only when the Charge Limit is set to 100% (Apple), and Apple notes your Charge Limit settings might limit Clean Energy Charging. If you set an 80% limit, the phone simply stops near 80% and there is little left for Clean Energy Charging to schedule.

How to turn Clean Energy Charging on or off

Go to Settings › Battery › Charging (iPhone 15 and later) or Settings › Battery › Battery Health & Charging (iPhone 14 and earlier), then switch Clean Energy Charging on or off.

To turn it off:

1. Open Settings › Battery.
2. Tap Charging (iPhone 15 and later) or Battery Health & Charging (iPhone 14 and earlier).
3. Turn off Clean Energy Charging.

To turn it on and make sure it works (Apple):

1. Turn on Clean Energy Charging in the menu above.
2. Go to Settings › Privacy & Security › Location Services and turn it on.
3. Tap System Services and turn on System Customization.
4. Tap Significant Locations & Routes and turn it on.

To skip it once without changing settings, touch and hold the Lock Screen notification and tap Charge Now.

Should you turn off Clean Energy Charging?

Leave it on unless it keeps leaving you with a partly charged phone. It costs nothing, does not change charging speed, and works only during long predictable sessions. Reasons people turn it off:

• Irregular schedule. If you sometimes leave hours earlier than usual (shift work, early flights), the phone may still be holding at 80%. Tapping Charge Now the night before solves this without disabling it.
• Privacy preference. It needs Significant Locations. Apple says the location is not sent to Apple, but some people prefer to keep that setting off.
• Using an 80% Charge Limit anyway. The feature then has almost nothing to schedule.

Reasons to keep it on:

• Lower emissions for zero effort.
• Less time at 100%, which overlaps with the battery-wear benefit of Optimized Battery Charging.
• It is a small, free example of demand flexibility — the same idea utilities want from EVs, heat pumps and home batteries.

Does Clean Energy Charging affect battery health?

No, it does not damage the battery, and holding at about 80% for part of the night is gentle on a lithium-ion cell. Apple designs Optimized Battery Charging to “reduce the wear on your battery and improve its lifespan by reducing the time your iPhone spends fully charged” (Apple). Clean Energy Charging uses the same pause-and-resume pattern, so its effect on battery health is neutral to slightly positive.

What it does not do is replace good charging habits. Heat is a bigger enemy of lithium-ion batteries than charge level, so avoid charging under a pillow or in a hot car. If battery longevity is your main goal, an 80% Charge Limit on iPhone 15 and later has a more direct effect than Clean Energy Charging.

What is the healthiest way to charge an iPhone?

Keep the battery cool, avoid long stretches at 100%, and let the iPhone’s built-in charging features do the scheduling. Lithium-ion cells wear faster when they are hot and when they sit at a full charge, so the practical rules are:

1. Leave Optimized Battery Charging on (or, on iPhone 15 and later, choose a Charge Limit such as 80–90% if you rarely need a full battery) (Apple).
2. Avoid heat. Do not charge under pillows, on a car dashboard in summer, or inside a thick case that traps heat during fast charging.
3. Do not worry about overnight charging. The phone manages the final stage itself; Clean Energy Charging and Optimized Battery Charging both hold it below full until shortly before you unplug.
4. Partial top-ups are fine. Lithium-ion batteries do not need full 0–100% cycles, and there is no “memory effect” to train away.

Should you charge to 80% or 100%? For daily use, 80–90% is gentler; charge to 100% when you need the full range for a long day or a trip.

How much electricity does charging an iPhone use?

Charging an iPhone once a day uses roughly 5–6 kWh a year, which costs about $1 at the US average residential rate of 18.2¢/kWh (EIA, August 2026). Working, with assumptions stated:

Step	Assumption / calculation	Result
Battery energy	Assume a ~13 Wh battery (about 3,400 mAh × 3.85 V), typical of recent standard iPhones	13 Wh
Charger and battery losses	Assume ~85% wall-to-battery efficiency → 13 ÷ 0.85	~15 Wh per full charge
Daily full charge for a year	15 Wh × 365	~5.6 kWh/yr
Cost	5.6 kWh × $0.182	~$1.02 a year

Your phone’s battery capacity and charger may differ; convert your battery’s mAh rating with the mAh to kWh converter and price it with the electricity cost calculator. If kWh is unfamiliar, start with what is a kilowatt-hour.

How much CO2 does Clean Energy Charging save?

For one iPhone, a few hundred grams of CO2 a year at most — small for you, meaningful only at the scale of hundreds of millions of devices. The estimate:

1. US electricity averaged about 0.81 lb (370 g) of CO2 per kWh in 2023 (EIA).
2. A year of iPhone charging (5.6 kWh) at that average ≈ 2.1 kg CO2.
3. Clean Energy Charging only moves the last ~20% of each overnight charge (about 1.1 kWh a year).
4. If those hours are 10–30% cleaner than average (an assumption; it varies by grid and season), the saving is about 40–125 g CO2 a year.

For comparison, driving a typical gasoline car emits roughly that much in under a mile. The honest takeaway: Clean Energy Charging is less about your phone and more about normalising when electricity is used. The same logic shifted onto a 60 kWh EV battery saves hundreds of times more — see the cost to charge an electric car and the EV charging cost calculator.

Why is Clean Energy Charging only in the US?

Apple’s support page lists it as on by default in the United States and does not mention other regions. The feature depends on reliable, local, forward-looking grid carbon forecasts, which are easier to build where grid operators publish detailed hourly generation data, as US balancing authorities do through the EIA. Users outside the US still get Optimized Battery Charging and, on newer models, Charge Limit.

History of Clean Energy Charging

Year	Milestone	Source
2019	Optimized Battery Charging arrives in iOS 13, learning daily charging routines	Apple
2022	Clean Energy Charging launches in iOS 16.1 (October 24) for US iPhones	Apple, AppleInsider
2023	iPhone 15 adds an 80% charge limit option	Apple
2024	iOS 18 expands Charge Limit to 80–100% in 5% steps on iPhone 15 and later	Apple

The bigger idea: carbon-aware electricity use

Clean Energy Charging is a consumer-facing example of load shifting: moving flexible electricity use to times when supply is cleaner or cheaper. Utilities pay for the same behaviour at much larger scale through time-of-use rates, smart EV charging and demand-response programs, because flexible demand lets grids use more wind and solar instead of firing up gas peakers.

Things you can shift at home, in order of impact:

1. EV charging (typically thousands of kWh a year) — schedule overnight or during solar hours.
2. Water heating with a heat-pump water heater on a timer.
3. Dishwasher, washer and dryer — use delay-start.
4. Home battery charging from rooftop solar instead of the grid.

Your phone is the smallest item on that list, but it is the one Apple turned on for millions of people at once. For the accounting side of “using clean electricity”, see our guide to renewable energy credits.

Bottom line

Clean Energy Charging is a US-only iPhone setting that pauses a long charge around 80% and finishes it when the local grid is forecast to be cleaner. It does not hurt the battery or slow normal charging, and you can override it with Charge Now or turn it off under Settings › Battery. The carbon saving per phone is small — a phone uses about 5–6 kWh a year — but the principle of using electricity when renewable energy is plentiful is one of the most useful habits on a modern grid.