The EPA addressed this question well on their Web page “Electric Vehicle Myths” (https://www.epa.gov/greenvehicles/electric-vehicle-myths). Here’s what they said:
FACT: Electric vehicles have charging strategies that can prevent overloading the grid, and, in some cases, support grid reliability.
It is true that the increasing number of electric vehicles on the road will lead to increased electricity demand. Yet, how that impacts the grid will depend on several factors, such as the power level and time of day when vehicles are charged, and the potential for vehicle-to-grid (V2G) charging among others.
EVs can be charged at off-peak times, such as overnight, when rates are often cheaper. Even with a mix of charging times (so not all nighttime charging), research indicates that sufficient capacity will exist to cover EVs entering the market in the coming years.6 And further down the road, when renewables make up a larger part of our energy mix in many regions, switching to more daytime charging (when some renewables like solar generate energy) with some energy storage capability should allow the grid to handle increases in EV charging. California leads the country with more than 1 million electric vehicles and EV charging currently makes up less than 1% of the state’s grid total load, even during peak hours.
EV charging consumed less electricity than water heating and air conditioning in a typical U.S. household in 2020, according to recent data released by the U.S. Energy Information Agency.
Vehicle-to-grid (V2G) charging allows EVs to act as a power source that may help with grid reliability by pushing energy back to the grid from an EV battery. This is done by allowing EVs to charge when electricity demand is low and drawing on them when that demand is high.
Long term, higher electricity demand from EV growth may drive the need for upgrades to transmission and distribution infrastructure. Planning for this possibility is underway. The Department of Energy’s (DOE) Build a Better Grid Initiative, launched as part of the Bipartisan Infrastructure Law, will provide over $13 billion towards improving the reliability and efficiency of the grid over the next decade. Visit DOE’s Bipartisan Infrastructure Programs and search “grid infrastructure” to see where the initial investments will be made.
Resources:
https://www.energy.gov/eere/femp/bidirectional-charging-and-electric-vehicles-mobile-storage
https://www.nature.com/articles/s41560-022-01105-7
https://www.scientificamerican.com/article/why-electric-vehicles-wont-break-the-grid/
https://www.eia.gov/consumption/residential/data/2020/index.php?view=consumption