Published on February 2nd, 2018 | by Steve Hanley0
NREL Finds Future EV Charging Demand Will Require Coordination Between Utilities & Car Owners
February 2nd, 2018 by Steve Hanley
Matteo Muratori, a researcher at the National Renewable Energy Laboratory in Colorado, wondered how having more electric cars on the road might affect local grid infrastructure. While it is true that there are relatively few EVs driving around America at the moment, he says if half dozen of them are clustered in a given area that is dependent on one transformer, the extra load can shorten the life of that transformer by up to 50%. Utility companies will need to either upgrade their transformers (which costs money) or commit to replacing them more often (which also costs money.) One way out of the bind might be to coordinate charging activity using smart grid technology.
Muratori used statistical data from the US Department of Energy’s Residential Energy Consumption Survey. He concluded that the grid as presently constituted could handle the needs of electric cars so long as they represented less than 25% of the total number of cars on the road in a given area and were charged with Level 1 equipment. But adding Level 2 chargers to the mix rapidly made significant upgrades to the grid essential.
“Realizing the full benefits of vehicle electrification will necessitate a systems-level approach that treats vehicles, buildings, and the grid as an integrated network,” Johney Green Jr., NREL’s associate director for mechanical and thermal engineering sciences tells Ars Technica. Muratori adds, “Previous research into the amount of energy required by homes hasn’t taken into account plug-in electric vehicles. Given that more people are choosing to drive these types of vehicles and charging them at home, this additional demand should not be overlooked.”
Smart grid technology, which can coordinate the charging activity of multiple cars, could alleviate some of that requirement for grid improvements. In a coordinated system, all the EV chargers would communicate with each other. Someone who leaves for work at 4 am would get priority earlier in the evening while a driver who leaves home at 8 am might have charging delayed until later in the evening.
The network would figure out which cars needed charging when and at what level of power. Utility companies could offer time-of-use incentives that would reward drivers for participating in the program with lower electric rates. Muratori also found that charging a little bit during the day at work or while shopping would help reduce the strain on residential segments of the grid. His study did not take into account vehicle-to-grid strategies.
Utility companies shouldn’t see more electric charger demand as a bad thing, he says. After all, electricity is their product. A shoe store wouldn’t necessarily find selling more shoes to be a bad thing, although it could cause problems if everyone came in between 1 and 2 in the afternoon for their new kicks, leaving the store empty the rest of the day.
“Matteo’s work raises important issues for a world with increasing electrification of the vehicle fleet, and leaves us with clear avenues for additional research,” says John Farrell, NREL’s laboratory program manager for vehicle technologies. “We need to continue looking at the synergies between electric vehicles and buildings, especially to make sure the grid remains safe and resilient.”