There are some ill-informed opinion pieces suggesting that the more EVs that are put to use, the more we'll need to tap into dirtier power sources in order to meet demand. 

But as a recent RMI report suggests, that's not true—because relatively simple tech like smart charging and time-of-use rates will help smooth loads and help utilities make the most of renewables.

Smart charging refers to technology that allows drivers to charge their cars at an optimized time, whether it's when electricity is cheapest, or when renewable sources like wind and solar are on stream. Synchronizing EV charging with renewable energy in this way can further lower overall emissions, according to the report.

Netze BW smart charging trial  -  screencap from Reuters

Netze BW smart charging trial - screencap from Reuters

In the United States, EVs currently produce 60% to 68% fewer emissions than gasoline or diesel vehicles, while implementing smart charging could lower that by a further 18%, according to RMI.

The more EVs on the road, the more powerful this effect, RMI argues. Today, charging one million EVs at the right time is equivalent to taking 20,000 to 80,000 internal-combustion vehicles off the road. When 70 million EVs are on the road—meaning one in four cars would be electric—emissions-optimized smart charging for that fleet would be like taking 5.73 million internal-combustion vehicles off the road.

EV drivers can already lower emissions based on their local grid mix, RMI noted. Drivers in the Midwest, which has a higher level of wind power, can reduce emissions by charging at night, RMI said, while drivers in California are better off charging during the day because of that state's greater reliance on solar power.

BMW Smart Charging App for i3 and i8

BMW Smart Charging App for i3 and i8

Leaving cars plugged in longer could also help, because it creates more flexibility to charge when grid emissions are lower, according to RMI. Plugging a car in overnight, for example, when only two or three hours are needed to charge, creates flexibility as to when charging an actually occur.

Smart charging could also be beneficial in other ways. California heat waves have helped emphasize that there's urgency to enact smart charging programs and incentives. And as more people plug in, smart charging could be just as important as fast charging in driving mass EV adoption.

Upgrades are definitely needed—but the push to wider adoption will incentivize this for everyone. And let's not forget that the ability to get greener with renewable energy will always be an advantage for EVs over gasoline and diesel cars.