How can the US power grid struggle with ACs in the summer, but be (allegedly) capable of charging millions of EVs once we all make the switch?


Currently we are told the power grid struggles to handle the power load demand during the summer due to air conditioners. Yet scientists claim this same power grid could handle an entire nation of EVs. How? What am I missing?

In: 20541

It would be slowly upgraded as the demand materialized.

Although many providers charge higher rates during summer afternoons explicitly to discourage users from running electrical demands during that time, and provide incentives to charge EVs at night.

EVs can be charged night time to balance the load. This reduces the need to have to use less efficient methods of channeling excess overnight electricity such as steam storage or resevoir pumping.

EVs charge at different rates at different times. Not every single car is going to pull 12kw. My car is a edge case but I slow change at 800w all night, that’s less than a microwave.

Most EVs can be programmed to start charging at a specific time, likely to take advantage of tiered electricity.

Considering the AVERAGE American drives something like 20 miles one way, most daily driver EVs can get away with a hour or two charging at night.

Going forward with this logic I can see smart plugs or EVSEs being used by utility companies. They can turn on chargers in phases as to not overwhelm generators. I imagine this mind experiment technology can be manually bypassed, like if you absolutely need a full charge before a morning road trip.

My kids owned an EV when they lived here, it used about 1/50 the amount of juice to charge as my 5-Ton AC unit.

The YouTube channel Engineering Explained [did a great in depth video on the subject. ](

It’s worth watching the full 16 minute video, but the answer is that the grid would need about 25% more capacity if every single person in the US switched to electric vehicles. And the grid operators can easily increase the capacity by 25%. The electric grid from 1960-2000 increased capacity by 4% per year, so it would only take about 7 years to fully increase the grid.

As for why it can get overwhelmed by AC during heat waves, that is a business choice not a physics choice. The grid could be designed to handle any demand from all the AC. But that only happens a few days a year and not even guaranteed every year. That peak capacity is wasted most of the time. This is especially true because thst demand is only for a few hours a day even on the worst days. A peak demand like that is the hardest and most expensive way to produce electricity.

EV charging is perfect for electric generation. You can charge during off peak hours, when the generators are otherwise idle (or worse, spinning down but still producing electricity). They also charge at a lower, steady rate.

Edit- had a few repeat comments so want to link my replies

Using EV as energy storage for the grid

About using batteries as storage to supply peak power (the whole comment chain has a great discussion, I just added to it)