Apple is getting a lot of flak for setting up iPhones to charge when the sun shines or the wind blows. The feature, called “Clean Energy Charging,” incited a tiny but vehement Twitter rebellion as critics, many of them right-wing personalities, slammed it as yet another “woke” front in the culture war. Others worried they would wake up to a depleted battery if their iPhones charged mostly when the grid is cleanest.
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All of this misses the quiet revolution this feature represents for you and the electricity grid. When it rolled out its new operating system in October,Apple proved overnight that millions of ordinary people willuse their devices to help manage the electricity grid, even if the vast majority of Apple’s 118 million iPhone users in the United States never realized it.
And that’s precisely the point. As America tries to electrify everything while adding gigawatts of new renewables, we need a way to dial down demand at critical times and soak up excess renewable energy at others. And we need to do this automatically.
Apple’s clean energy feature is a preview of how we’ll do it. Eventually, this flexibility means the U.S. grid can lower emissions and energy prices — while rewarding people to enlist their devices in the intelligent grid.Should you keep the iPhone feature on? Your call. But here’s what it means for you — and a clean energy future.
Filling gaps in the grid
Balancing supply and demand on the electricity grid is a delicate dance. Too much, or too little, and the grid can go down. Renewable energy, generally the cheapest option on the grid, tends to be dispatched first. But it often fluctuates dramatically over the course of a day.
Take California. Every morning, as the sun hits millions of solar panels across the state, the grid is flooded with clean, abundant solar power. There’s often a surplus. Last April, California’s grid operator had to effectively turn off nearly 600,000 MWh of wind and solar power, the equivalent of two months of electricity from the Hoover Dam, because no demand or storage existed.
Then the situation reverses. Every night, as the sun sets, solar power ebbs and utilities must find new supplies, mostly from carbon-intensive fossil fuel plants.
When there’s not enough electricity to go around, grid operators have two choices: impose blackouts or curb demand by calling on big energy consumers to turn off their machines and beg the public to ease up on air conditioning.
This imbalance may only get more challenging, says Mike O’Boyle, who directs the electricity program at Energy Innovation, a nonpartisan climate think tank. California aims to reach 90 percent zero-carbon electricity by 2035, and the United States hopes to achieve net-zero emissions by 2050. O’Boyle estimates the country will need two to three times more electricity on the grid than before, with most new capacity from renewables, and all that variability.
You and I are part of the solution — or, at least, our devices. Households and small businesses consume most of the electricity in the United States. If we want to decarbonize as cheaply as possible, the key is to be more flexible about when we use electricity.
Americans have cut back when they’re asked during emergencies. But attempts to change people’s behavior by charging more for electricity at peak times have had only a modest effect, reducing household consumption by 2 to 3 percent. “You can’t really rely on people over time to adjust their habits for small bill savings,” says O’Boyle. “People need technology that manages it for them.”
So let the machines do it for us.Until recently, that wasn’t possible.The iPhone was the first deviceto coordinate millions of customers’ energy use to favor renewable energy. By enabling this across the United States, it showed how nearly a third of the U.S. population would join this kind of grid management virtually overnight, if you make it easy enough.
How iPhone clean charging works
Apple, known for secrecy, would not comment on exactly how its clean charging feature works. Based on public statements, however, Apple appears to estimate when your local energy grid is cleanest by forecasting solar and wind energy production in the United States. It then shifts some charging to these periods if you’re unlikely to be on the move. When the phone sees you’re in a new location, traveling or have irregular charging habits, it remains off, according to the company.
I’ve personally never noticed a difference: My phone is always fully charged each morning, and starts charging when I place it on a wireless charging mat. While I can’t confirm precisely when the feature adjusts my charging, it appears to ramp up after 9 p.m., just after peak hours pass in California. Although the feature is turned on when you upgrade to iOS 16.1, you can override it (go to Settings > Battery > Battery Health & Charging). Since debuting six months ago, few have publicly noted the feature’s existence, suggesting not many people have experienced a difference.
This gets interesting when Apple’s approach is applied to electric vehicles, heat pumps, refrigerators and other major devices and appliances. Algorithms can slow or stop charging when electricity supplies are tight and prices are high, and discharge power back to the grid to fill in gaps between renewables. Millions of machines can act in concert to adjust their temperature by 1 or 2 degrees, sometimes preheating or cooling in advance, to spare the grid with their owners none the wiser.Utilities may even pay you, or lower your rates, for the service.
To see what that looks like today, drive 52 miles north from Apple’s headquarters in Cupertino to Lawrence Berkeley National Laboratory.
Intelligent grid escapes the lab
Scientists there are testing ways to connect devices with the electricity grid over everything from WiFi to FM radio signals across California. A computer server sends out real-time data about electricity prices and carbon intensity from utilities. A handful of heat pumps, air conditioners and other appliances then cycle up or down in response at homes, schools, offices and apartment buildings across the state, says Mary Ann Piette, a senior scientist at the laboratory. By adjusting the temperature a few degrees, these appliances essentially store energy in buildings to ride out periods of high prices and emissions on the grid. “Flexible load is a type of energy storage,” says Piette.
It’s all boring, behind-the-scenes infrastructure, but it will enable emissions and prices to fall without households flipping a switch. Once people enable such devices en masse, says Piette, the costs of electricity prices could fall 10 to 17 percent based on one Texas study, as the grid becomes far more flexible and cleaner. Within a few years, she estimates, homeowners in California could be fine-tuning their own electricity mix. “Buildings could be run as clean as possible with a slider that says, ‘I want to be as economic or as green as possible today,’” she says. “In the future, people will have a choice.”
You might even own these devices already. LG refrigerators, for example, come preloaded with software that, once connected to the grid, can adjust their energy consumption. A few groups such as OhmConnect, Octopus Energy and Silicon Valley Clean Energy offer to pay their customers a small sum to plug in things like electric cars and heat pumps into the beginnings of the smart grid.
“We’re moving to a time when devices will listen to grid signals every hour of the year and become intelligent enough to shift their load to the cleanest and the cheapest times,” says Piette. “That is the future.”
If you’d like to live there now, feel free to keep that iPhone feature on.
A previous version of this article incorrectly said a phone charger draws about 7.3 kilowatts per year. It is 7.3 kilowatt hours per year. The article has been corrected.