California needs to charge electric vehicles during day, not night, to save grid, study says
A new study in the journal Science Advances has found that California’s electric vehicle infrastructure could be running on “night and day” during the peak-demand hours of the morning and evening, resulting in a net loss of power in the grid due to insufficient charging, and potentially a net gain in peak power.
Researchers from the California Energy Commission, the University of California at Berkeley and the University of California at San Diego analyzed an eight-year series of California electric vehicle charging data from the San Diego Supercharger, which is the largest public charging network in the United States. The supercharger is a station equipped with multiple charging stations that can charge electric vehicle batteries at a very rapid rate of 4 to 21 miles per hour, depending on the size of those batteries, and the speed of the charging process.
From the data, the researchers could estimate how many cars were charging at the supercharger during normal, normal-peak, and high-peak conditions.
They found that during non-normal peak-load hours, “charging occurs during the peak-demand hours of the morning and evening,” the researchers wrote in the paper.
Using simulation modeling, the scientists analyzed how such a system would affect the electricity grid. They found that, by charging during peak-demand hours, the system reduces the total amount of electricity produced during peak demand hours, and thereby the capacity of the electric grid to meet peak load demands, which include electric vehicles.
“More importantly, in a high-demand scenario (e.g., peak-load), the loss in electricity during peak-demand hours leads to the loss of electricity during the whole day, and consequently impacts the reliability of the grid,” the researchers wrote in the paper.
This “loss of peak power could reduce the reliability of the grid.”
“In a high-demand situation (peak load),” the researchers wrote, “the loss in electricity during peak demand hours leads to the loss of electricity