“The transition to electric vehicles will take place over many years,” said Rob Threlkeld, General Motors global manager of sustainable energy, supply and reliability. “Automakers are working with utilities to optimize it.”
“The (electric) grid is well equipped to supply EVs today and in the near-term,” said Samantha Houston of the Union of Concerned Scientists
The key is for EV owners to do most of their charging at night, when a lot of the electricity generating capacity that already exists is idle. Most utilities will offer low rates to encourage owners to charge then.
DTE Energy customers charge about 15,000 electric vehicles in southeast Michigan, 22,000 throughout the state. About 90% of charging takes place outside peak hours, generally between 11 p.m. and 7 a.m. Residential users can sign up for a discounted rate during that period, 11 cents a kWh under DTE’s EV plan, compared with 24 cents/kWh the rest of the day.
Charging at roadside commercial facilities will cost more than the discounted off-peak rate for homes. How much varies, depending on location, charging company and more.
Off-peak electric demand can fall 50% from midday peaks, Threlkeld said.
“There are thousands of megawatts that are online during the day and offline at night. That can charge a lot of EVs.
“Optimizing the time of charging is the key to making use of existing generation capacity,” Threlkeld said.
Off-peak charging is part of the reason EVs should be less expensive to operate than gasoline or diesel vehicles.
That’s because huge power plants that can handle midday surges operate less efficiently off-peak.