NYSEG, Cornell professor work on program coordinating electric car-charging times

ITHACA — New York State Electric and Gas (NYSEG) is working with a Cornell University professor on a program to coordinate electric-vehicle power use by encouraging owners to delay charging times in exchange for lower prices.

The project, OptimizEV, will involve 35 participants in Tompkins County for a year to better understand consumer charging preferences, and how these might align with the overall power grid, per a Cornell University news release.

NYSEG is working with Eilyan Bitar, associate professor of electrical and computer engineering, on the project. 

Owners of electric vehicles tend to come home in the evenings and plug in their cars, straining the grid because they’re demanding a lot of power at peak times, Cornell said. Even with plans offering off-peak discounts, most electric car owners still charge their cars at the same time to take advantage of lower prices, which also strains the grid, though at different hours.

“When most people plug their vehicles in, they don’t always need them to be charged immediately, and even though they won’t need them until the following morning, they’re plugged in for the rest of the night,” said Bitar, who is also a fellow with the Cornell Atkinson Center for Sustainability.

How it works

Participants in the pilot will use smart chargers that can communicate to NYSEG their energy usage minute by minute. Electric-vehicle owners will indicate how long they plan to leave their cars plugged in, choosing from a menu of options that offers larger discounts the longer they’re willing to delay.

Once customers make their selections, an optimization algorithm will consider their deadlines, their energy usage, and the wider demand on the power grid in order to determine the optimal charging pattern for every vehicle being managed.

“That will allow us to both monitor electric-vehicle charging and to transmit control signals that let us adjust the power they’re drawing in real time,” Bitar said. “We’ll reshape the electric vehicle power load patterns to minimize strain on the grid, while still respecting customers’ charging preferences and personal deadlines.”

Bitar developed the optimization algorithm along with Polina Alexeenko, a doctoral student in electrical and computer engineering, Cornell said.

Smart chargers have been installed in the homes of the 35 participants, and preliminary monitoring will continue through the end of the year. The pilot is expected to be completed in late 2020.

Power demand for electric vehicles is “growing” as more consumers use level- two chargers, which are faster and more powerful than level-one chargers, but can double a household’s peak power demand. The popularity of these chargers, combined with the increased adoption of electric cars, could jeopardize the utility’s ability to deliver power cheaply and reliably.

“Our grid infrastructure has limited capacity,” Bitar said. “Transformers can only accommodate so much demand at any given moment. Exceeding a transformer’s capacity to serve demand can severely reduce its lifetime, requiring more frequent replacements — which is not cheap.”

OptimizEV is part of NYSEG’s Energy Smart Community Initiative in Tompkins County, and was developed in partnership with Kitu Systems of San Diego, California; Taitem Engineering in Ithaca; and supported in part by the New York State Energy Research and Development Authority (NYSERDA).