Referred to as “vehicle to grid,” two-way charging works by sending power to the grid from an EV’s battery while the car is parked and plugged in. Though promising, the technology remains in its nascent stages and comes with significant costs, which has partly stalled its widespread adoption.
The PG&E grid has faced a barrage of challenges from extreme weather. An unprecedented series of drenching atmospheric rivers this past winter led to prolonged outages that left residents and city officials frustrated. The utility has plans to invest billions of dollars to fortify its grid against wilder weather.
To mitigate another major risk — wildfires — PG&E is also resorting to deliberate power outages in high fire-risk zones, to prevent its power lines from sparking blazes.
Poppe says these EVs can play a significant role in contributing to grid stability, particularly during periods of high energy demand and solar power shortages.
California, already home to more than a third of all registered EVs in the US, is primed for further growth as the state mandates that all new vehicles sold must be electric or plug-in hybrids by 2035.
In PG&E’s service area alone, which spans from Northern California to the Central Valley, Poppe said there are enough EVs on the road to return roughly 9,000 megawatts of power to the grid — nearly the equivalent of five Diablo Canyon Nuclear Power Plants.
With bidirectional charging, drivers can take advantage of California’s abundant solar energy during the day to charge their cars, subsequently returning power to the grid during crucial evening periods when demand surges — especially during summer heat waves when air conditioners are running full blast, functioning as an emergency backup power source.
Utilities will need to offer drivers incentives, such as paying them for the kilowatt hours they contribute. One study estimates ratepayers could save as much as $1 billion a year from using the technology.
However, some EV owners have reservations about the potential impacts on their car battery’s lifespan, while concerns linger about the installation adding an estimated $3,700 to an EV’s cost, according to the Alliance for Automotive Innovation.
PG&E conducted a pilot project last year with GM, which is planning to offer bidirectional charging in some models, including the 2024 Chevrolet Silverado, according spokesperson Sanaz Marbley. The company is committed to an “all-electric future” and is exploring new options, Marbley said.
Two-way charging is also gaining support from the California Legislature. A bill written by state Sen. Nancy Skinner would require all new electric vehicles sold in California to have bidirectional charging starting in 2030.
Mark Chediak contributed to this report.